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1. 6 AN NM H M B 6 DXE M B 6 APPENDIX C WinGMM Glossary e eet etl ets e el ed eee ele ite iol edge e d ete neces 1 iv GCDB WG TRN V1 00 10262001 INTRODUCTION TO GEOGRAPHIC MEASUREMENT MANAGEMENT FOR WINDOWS USER GUIDE Geographic Measurement Management for Windows WinGMM is a suite of programs designed for data entry computation and analysis of survey information necessary to support the Geographic Coordinate Data Base GCDB These programs are capable of translating data entered from graphic sources into a configuration usable by numerous processes in an electronic automated environment The Public Land Survey System PLSS grid is not always correctly displayed on some maps that are commonly digitized to obtain coordinates for corners In addition some features of the PLSS grid particularly corners of some special surveys such as river meanders and Tracts are not usually shown on maps and therefore the coordinates of these PLSS corners are not available WinGMM was initially developed to 1 compute the geographic coordinates for corners of the PLSS using official survey record data 2 provide an estimate of the positional dependability of the computed corner coordinates 3 preserve the survey measurement data and resultin
2. 00sec ecc 1 Appendix B File Formats for WinGMM Data Files 0 0 cece cece B 1 Appendix Gloss rt e e be ede E usse ETE Dee 1 APPENDIX GCDB WG TRN V1 00 10262001 APPENDIX A GCDB NAMING CONVENTIONS TOWNSHIP NAMING CONVENTION Eight Characters A normal township would be called T23NRO7W If a township or range has a fraction has a value over 100 or a combination of the above the T or R is replaced with a letter code If there is a duplicate or triplicate township the R is replaced with a letter code Some townships have a duplicate or even triplicate The township that has its SE township corner closest to first the baseline then the principal meridian if necessary to further differentiate will get a normal letter code The next closest gets a duplicate letter code and the next closest after that gets the triplicate letter code The following quick reference chart and cross reference chart shows the letter codes to use and cross referenced examples Quick Reference Chart What character replaces the T or R eme s o mum _ ao 9 u a s L A Cross Reference Chart for various BLM Township Naming Conventions Survey Plats Notes WinGMM LR2000 DED PCCS R file T22N R1W T22NROIW 0220N0010W R22NOIW T22N R1E T22NROIE 0220N0010E R22N01E TI4N R4W TI4NRO4W 0140N0040W R14N04W T112S R6W HIISRO6W 0112500
3. Corners that are not full section corners are incremented by the number of whole chains they are away from the southwest corner of the section This affects the tens place or second digit of each pair XxxYyy For example 120600 is the west sixteenth corner of the section line between Sections 6 and 7 and is 20 chains away from the section corner 100600 Refer to Figure A 2 Section 8 with GCDB IDs down to the 1 16th level The third digit Xxx Yyy ones place in the x or y coordinate has special functionality in the post processing functions The recommended values for these are O arectangular corner point Example 160660 is the NE 1 16 corner of Section 6 The standard point identifier for a section corner indicates that the corner is a maximum interior control section corner common to four sections Refer to Figures A 1 and A 2 1 2 8 or 9 1 e 1 o2from a rectangular corner is used for offset corners no matter what the actual distance of the offset usually on the interior of the township The database will default to the value for interior offset section corners See Figure A 4 GCDB IDs for offset corners in township interior 3 or 7 1 e 3 from a rectangular corner is used for offset corners no matter what the actual distance is of the offset usually on the boundaries of a township APROPW will determine that these are corners angle points etc from adjacent townships See Figure A 3 GCDB IDs for offset corners along
4. Residual vs error estimate These quantities should be of approximately the same magnitude Since measurements contain random error a plot of residuals should look like the bell shaped curve from statistics that centers about zero If residuals tend to be predominantly of one sign this means systematic error may exist This would occur if your survey tied into two precise control coordinates and your EDM was measuring systematically long All adjusted distances would be shorter than their measured values It could also occur if horizontal angles were only measured in the direct position and a large horizontal collimation error existed Residuals which are larger than three times their respective error estimate are generally considered suspect RMS error root mean square error it is the average of a series of residuals in which the sign of the residual is eliminated through summing squared residuals dividing by the number of that type of measurement then computed that value s square root Robustness This is a method of using least squares as a filtering mechanism for detection of blunders Robustness averages the absolute value of a measurement s residual with its error estimate and that average becomes the new error estimate in a readjustment The measurements with large residuals get reassigned larger error estimates and vice versa This enables the adjustment to be filtered to the suspect measurement The success of robustness in blunder
5. Geographic Coordinate Data Base Geographic Measurement Management For Windows WinGMM Version 1 00 10262001 WinGMM Technical Reference Manual L amp RPO GCDB WG TRM V1 00 10262001 October 26 2001 United States Department of the Interior Bureau of Land Management Land amp Resources Project Office Denver Federal Center Denver Colorado 80225 0047 GCDB WG TRN V1 00 10262001 WinGMM TECHNICAL REFERENCE MANUAL TABLE OF CONTENTS GCDB BACKGROUND AND HISTORY ocacion att ed italia calida 1 1 GCDB COMPUTATIONS USING WINGMM S LEAST SQUARE ANALYSIS ect 1 2 CONTROE COORDINATBES 23 2 teret eode et eet eer cetero de eere EC Pe e EE 1 2 COMBINING SOURCEDATA 1 x ta ated eei a m dete ep e 1 3 WINGMM USES THE TECHNIQUE OF LEAST SQUARES ANALYSIS esee nee 1 3 EASE OE MAINTENANGCE n RD RR iz 1 4 COORDINATE GEOMETRY IS USED TO FURTHER DIVIDE THE MEASUREMENT NETWORK 1 4 ABSTRACTION ui rerit dae tester cei e lora 2 1 CHAPTER INTRODUCTION Het eee edet Preterea ferte deett 2 1 o oe emet ete eee e eet edis ot otto LE etie A e toe p p eee Pe e Lo ied 2 1 Diana tilda il iii 2 1 ABSTRACTING A STANDARD RECTANGULAR TOWNSHIP 2 1 ABSTRACTING SPECTAL SURVEYS 2 2 ABSTRACTING MEANDERS 300 A eo Eads RS TEE Ea 2 2 PREPARING THE COMPUTER FOR NEW TOWNSHIP ccccnnnnnnnnonnncnonon
6. TO3NR17E TO3NR18E TO3NR19E TO3NR20E TO3NR21E TO4NR17E TO4NR18E UTILITIES 9 5 GCDB WG TRN V1 00 10262001 TO4NR19E TO4NR20E TO4NR21E GCONHPW will run thru the list reading the DEF file of each project to determine which DATUM to convert to As it does a conversion it changes the DEF file DATUM to the proper DATUM projects in NAD 27 must first be converted to NAD 83 with GCONW before they can be converted to the HARN datum Therefore all projects in the list must be in NAD 83 CSTUF The cstuff exe program is a utility that performs coordinate geometry calculations on coordinates that exist within the cor file for any given project Cstuff exe requires a def and cor file in order to operate QCMAT The qcmatw exe program creates QC LSA QC COR and QC INF Report from Region LSA and MAT files This is a similar quality control tool as used by formlsaw exe that can be used to view matches and mismatches between exterior project boundaries UTILITIES 9 6 GCDB WG TRN V1 00 10262001 LINKING GCDB TO THE LLD LINKING THEORY The purpose of the WinGMM Linking process is to support the BLM s Legacy Rehost 2000 LR2000 system It is not within the scope of this chapter to explain LR2000 This chapter will explain the linking process and only include information regarding LR2000 that pertains to linking For a more in depth dissertation of LR2000 contact the BLM office of your choice One component of LR2000 is a produ
7. junk SID or sub SID see INRAWW below with error estimates based on the actual adjustment in ADJ and edit the suspect lines in the RAW file to that SID If no obvious errors are found in bearings robust twice on control to see if the error becomes isolates in a particular control point If all these steps still fail to identify the error you must assume the control is good and proceed accordingly The goal is to keep the residuals on any control used in an adjustment to within a reasonable proximity of your original error values Scenario 3 After importing a boundary from an adjacent township the residual values on the boundary become very high Scenario 4 After importing a boundary from an adjacent township residual values are excessively high on the lines running into that boundary Both of these problems are by products of holding transferred boundaries fixed This logically requires movement of survey measurements along or into the fixed corners It must be recognized and dealt with as an un avoidable evil in the boundary transfer regime One solution is to create a boundary transfer SID or sub SID INRAWW with a lower weight to place these lines into A more efficient and preferred approach to these scenarios is the regional adjustment as outlined in this WinGMM User Guide REGION As discussed changing original error estimates on control should be avoided While we attempt to put legitimate error estimates on survey data to
8. 2345 683125 6772 140 000 0 0 2000 0000 5000 0000 EXAMPLE OF COMMENT 100100 451019 2345 683125 6772 140 000 8 3 27 100200 451029 3457 683126 1267 140 000 3 100 83 EXAMPLE OF COMMENT 2 100300 451129 5671 683127 1234 140 000 9 52 27 EXAMPLE OF COMMENT 3 EXAMPLE OF COMMENT 4 This is the same con file after GCONW TEST CON ABSTRACTION 2 4 ORIGIN 451019 2345 683125 6772 140 000 0 027 ORIGIN 451019 4482 683123 7636 140 000 0 0 83 EXAMPLE OF COMMENT 100100 451019 2345 683125 6772 100100 451019 4482 683123 7636 100200 451029 3457 683126 1267 100200 451029 1324 683128 0404 EXAMPLE OF COMMENT 2 100300 451129 5671 683127 1234 100300 451129 7780 683125 2088 EXAMPLE OF COMMENT 3 EXAMPLE OF COMMENT 4 140 000 140 000 140 000 140 000 140 000 140 000 8 8 3 3 9 9 3 27 3 83 100 83 100 27 52 27 52 83 GCDB WG TRN V1 00 10262001 Note columns 56 57 are reserved for a NAD27 NAD83 or HARN If it is blank or something besides NAD83 or HARN is there a NAD27 is assumed Thus present CON files all NAD27 will work fine without the NAD27 in the file 2 5 ABSTRACTION GCDB WG TRN V1 00 10262001 DATA ENTRY AND EDITING INRAWW CHAPTER INTRODUCTION This chapter deals with getting information from the survey plats or abstraction sheets into the computer In WinGMM this task is done by INRAWW Please refer to INRAWW Program Reference for additional details Data entry also ref
9. 5 5 GCDB WG TRN V1 00 10262001 STATION NORTHING Y NORTHING Y EASTING X EASTING X RESIDUAL EST ERROR RESIDUAL EST ERROR 100100 7 309 2 30 000 43 951 1 5 30 000 100200 5 818 2 30 000 25 101 8 30 000 100500 40 152 1 3 30 000 10 616 4 30 000 repeat for every control point used in the adjustment At the bottom of the control section of the ADJ file a listing of the average adjustment average snoop value and maximum adjustment in northing and easting is listed and looks like this NORTHING CONTROL RMS 25 257 SNOOP RMS 1 1 MAX NORTHING RESIDUAL AT 600100 OF 64 569 EASTING CONTROL RMS 32 390 SNOOP RMS 8 MAX EASTING RESIDUAL AT 500300 OF 69 382 DISTANCES The next section of the ADJ lists information regarding every distance input consisting of From point identifier To point identifier input distance how much that distance was adjusted residual a snoop value and the input error estimate and looks like this MINIMUM DISTANCE RESIDUAL PRINTOUT 000 DISTANCES OCCUPIED SIGHTED DISTANCE RESIDUAL EST ERROR STATION STATION 700100 700200 5280 000 012 0 6 224 700200 700300 5280 000 1 538 2 6 224 700300 700400 5280 000 011 0 6 224 repeat for every distance At the bottom of the distance section of the ADJ file there is a listing of the average adjustment average snoop value and maximum adjustment of the entire data set that looks like this DISTANCE RMS ERROR 2 335
10. LINKING GCDB TO THE LTD ii ipe Pob Re pen Pp E p ex pen eres 10 1 LINKING THEOR Y rai pt emiten epe e elt eene edet 10 1 UNDERSTANDING THE PORTION OF LLD NECESSARY FOR LINKING eene 10 1 COMBINING GCDB AND LLD WITH THE AN FILE esee ennemi 10 2 LINKING PROGRAM ORDBER 2 3 tuere tote gei e eder dte i Dee wd act e E A i 10 3 GETM E Derrotas iaa E P Ee a be 10 3 BRPEQY anon Aa Remise 10 3 J E D D iss cscs 10 3 E itm tto te a RO OE EHE EE NOD UH SEO HEU RR ees LIE CO atop NON 10 4 dm 10 4 P WP 10 4 sass ET 10 4 APPENDIX A GCDB NAMING CONVENTIONS esee nennen Henn netnretne teens ense nnn nns 1 TOWNSHIP NAMING CONVENTION Eight Characters eese nnne 1 SUMMARY oii iens eame e tee ree P A Dedi rete Poe Veo Fee abre 6 APPENDIX B FILE FORMATS of WinGMM FILES eese nete teens B 1 TEMP JOB 00d do B 1 DEE 5e aee b cos ves sts ree reds she Ls Lo LR rod E rte LT B 1 1 CON 2 RAW e ann a ena e e na e B 3 ES EE B 3 QD atento Re re enm n ree pe B 4 ADD s E Am nde nm Inm I mm sm mM B 4 NOT a OR 5
11. QCMAT to determine if the merge was successful The lines shown in the display are those that have merged NOTE It is possible to make a DXF file from QC LSA and view it in AutoCAD 5 Run LSGMMW because of the size of these multi township adjustments the larger versions of LSGMMYW should be used on the PC The version may also be dependent on the configuration of the PC 6 Run FORMCOR to parse out the individual township COR files FORMCOR will create COR GEO and PGC files for each individual township FORMCOR uses the region MAT file created by FORMLSA to associate a township ID with a big adjustment ID If you computed error analysis in the big adjustment these are transferred to the proper PGC file The individual township LSA file s coordinates are updated 7 Follow the steps below to setup and run FORMREL Run FORMREL when error analysis is turned off or fixed boundaries were used FORMREL calculates reliabilities for each township above the NOREL line in the HOW file and updates the reliabilities in their PGC files If properly setup FORMREL will use the data from ALL townships in the region including the townships used for the FIXED boundaries to calculate reliabilities for the target townships A Backup your COR HOW LSA MAT and SD files by renaming them i e 1CO 1HO 1LS 1MA and 1SD for future use B Reformat your HOW file to include all townships by deleting the FIXED line from it C Run FO
12. The an2iidw exe program converts PCCS attribute AN files to IID file format Since GMM is now the official collection software for GCDB and because WinGMM requires an iid file for maintenance of the attribution of legal land descriptions within a given project this program performs a conversion that will allow maintenance of attributes in the future The program reads DEF COR INT and AN files If there is mismatch between the INT and AN files the program stops and warns the User and is then prompted to press the ENTER button to continue The offending parcels are then labeled with the word ERROR in the IID file Searching with a text editor to find the word error within the IID file will inform the User of possible conflicts If AN2IID does not stop it is assumed that no conflicts exist between the AN and INT files AN2GLD Input files AN Output files GLD The an2gld exe program converts a previously created AN file to the newly identified GCDB Legal Land Description GLD file The GLD file contains a number of new entity fields such as discrepancy acreage source conflict and validation codes which are populated with null values when this program is run These LINKING 10 4 GCDB WG TRN V1 00 10262001 new entity fields will be populated with actual data once the National Integrated System is deployed LINKING 10 5 GCDB WG TRN V1 00 10262001 APPENDIX CONTENTS Appendix A GCDB Naming Conventions
13. be used to control subsequent subdivision processes Non computables Sometimes corners exist that would be computed wrong if the section was subdivided using normal rules First you tell the IRR file that these corners are non computable and then you put the correct solutions in the ADD file Otherwise APROPW might generate wrong coordinates for these corners and then will ignore your instructions on how to compute them correctly Reason APROPW will not compute a corner whose coordinates already exist An example non computable corner is the N 1 4 corner of sec 2 corner 540700 from Figure 7 2 above In a case like this you want to define 540700 to be at intersection of the N boundary line 543700 503700 with the weighted mean bearing from 540600 APROPW would normally compute 540700 at midpoint easting between 500700 and 600700 and on the N boundary line which is not exactly right with such a large bearing of the N line You would define 540700 to be non computable Then after computing 540640 at intersection weighted mean bearing from 540600 500640 600640 540700 can be computed as an intersection of the N boundary with the N S centerline through 540640 What happens in this example When you leave APROPW with the 8 PROPORTION AND QUIT 3 UPDATE COR GEO option the ADD file is read and all corners in it will be computed if possible Corner 540700 will not be one of those corners since 540640 has not been computed APRO
14. data it will be left to the individual user to determine which steps in the process below should be run on a regular basis 1 Copy the ORIGINAL SID created in step 4 above to the project SID file 2 Run INRAWW using all available control GEN LSGMMW and SNOOPER If LSGMMW won t run or the solution diverges you have bad control data of some kind Run RAWW to find the error If there are no apparent errors set robusting on in PROJECW and robust twice on control to localize the problem keeping in mind robusting must not be used in deriving a final LSGMMW adjustment 3 Review the ADJ file to analyze how much each control point was moved RMS values for control distances and bearings and the CHI Squared test Also look for asterisks 4 Review the REP and JNK files created by SNOOPER Note that each run of SNOOPER appends the results to the end of this file and so contains a history of what has been done and the effects on the data 5 As errors in control are found and addressed return to step 2 Any errors in RAW data that weren t found in the previous strategy for tracking down those blunders will rarely not never justify rerunning that process In many cases the survey and control data support each other When this happens no control point will move more than it s estimated error all RMS values will be acceptable and the CHI Squared test will pass BLUNDER DETECTION 5 9 GCDB WG TRN V1 00 10262001 When survey and control
15. detection is a function of size of the blunder number of blunders and the geometry and redundancy of the traverse network Simultaneous Solution This means all coordinates are being solved for in one solution in the compass rule process you must adjust one traverse into another traverse which is held as fixed This is not correct since the fixed traverse contains error Solution Convergence the last iteration has insignificant updates and thus the solution terminates Solution Divergence blunders or poor initial approximations will cause updates to grow as iterations proceed This indicates something is wrong with the data and it needs to be corrected Standard error of unit weight This is a number which tells you how well it appears that you are estimating your measurement errors It is generated by the summing the squares of all residuals divided by their error estimates That quantity is divided by the degrees of freedom and the square root is taken If a residual and error estimate are of the same magnitude note that the residual divided by the error estimate will generally produce a number close to one The standard error of unit weight is a number that evaluates all residuals and corresponding error estimates If the standard error of unit weight is near one 0 7 2 5 you are estimating your errors well Uncorrected systematic errors blunders or generally poor measurements will result in larger residuals and thus a large standard
16. from the respective functions and only upon your command IF YOU NEED TO THEN USE INRAWW FEATURE Add plat data 1 2 ADD RECORD INFORMATION Change plat data 1 3 EDIT RECORD INFORMATION Delete plat data 1 4 DELETE RECORD INFORMATION Add control data 4 2 ADD CONTROL Change control data 4 3 EDIT CONTROL DATA Change estimates 4 7 BLOCK EDIT ESTIMATES Delete control data 4 4 DELETE CONTRL Add SID data 5 2 SIDS Change SID data 5 3 EDIT SIDS Delete SID data 5 4 DELETE SIDS RAW DATA ENTRY 3 5 GCDB WG TRN V1 00 10262001 ADJUSTMENT AND ANALYSIS OF GEOMETRIC DATA CHAPTER INTRODUCTION As mentioned in the introduction to this User Manual WinGMM is designed to merge two kinds of data that sometimes conflict Both the control and survey data are given error estimates for this purpose and these error estimates play a very important role in the adjustment and analysis of the two data types The program GEN prepares the data for Least Mean Square Adjustment LSGMMW is a term we use to describe the adjustment via a variety of Least Mean Square programs LSGMMW also provides an analysis of the adjustment The process is a repetitive cycle of adjustment and analysis of the data until adjustments become so small as to become insignificant Normally LSGMMW runs without any user input the exception being when robusting is turned on The robusting process is described in more detail in this Use
17. graphics programs For tracking down the not so obvious errors you can use robusting to localize the adjustments into the areas where data isn t fitting Once blunders have been removed from the RAW file robusting should be abandoned LSMINW is run to make a permanent copy C MIN of the adjustment of the plat data Then the remainder of the CON file is imported and the network is readjusted via GEN and LSGMMW It is at this time that bad control or bad point identifiers for good control can be found and fixed GEN Technique Interpreting the GEN file The GEN file is your first opportunity to review how the data fits together geometrically There are three kinds of information contained in the GEN file that are useful in finding blunders The first part consists of loop closures around all sections possible based on the survey data contained in RAW and looks like this OKK K K K OK K K K K K K K K K K K K LOOP TRAVERSE REPORT FOR SECTION 17 CLOSURES NORTHING Y EASTING X LINEAR PRECISION TRAVERSE DIST 5 8 9 FT 5 8 FT 1 3641 4 0 MI STATIONS IN TRAVERSE 200400 200500 240500 300500 300440 300400 240400 200400 KOKK K K K OK K K K K K KK K K K K K These sections are very useful in tracking down blunders as we expect the plats to close within the limits BLUNDER DETECTION 5 1 GCDB WG TRN V1 00 10262001 required at the time of survey The obvious exception to this would be is when the data for a section is c
18. information stored within the database will remain stable what will improve over time are coordinate values of established corner positions WinGMM users can in one process combine two well defined types of geometric data The first is control point data derived from various sources This data consists of coordinate pairs that may be digitized from USGS quadrangle sheets derived by traditional methods terrestrial traverses or collected using Global Positioning System GPS The second type of data is derived from survey records This survey data consists of bearing and distance information entered from the official plats Both types of data contain a wide range of quality and must be resolved and analyzed to ascertain reliability We have only a nebulous idea of the merit of any given piece of data and only mathematical analysis will reveal the true quality of how each point and line statistically fit the combined data set By identification of reliable data it is possible to make low precision data less influential in its effect on the overall scheme CONTROL COORDINATES information about monumented points Visiting a specific monument and collecting survey measurements to determine latitude longitude Lat Long is a special and expensive process one that was not often done before the advent of some of the newer measuring methods i e GPS Surveyors are comfortable with the concept that no true or exact values are ever known for any measureme
19. is ended with a 0 or 1 The 1 signifies the end of the segment SD The SD has 4 segments Below is a shortened list 700503 33 000 33 0000 700600 33 000 33 0000 700603 33 000 33 0000 700700 33 000 33 0001 100100 100200 32 680 0 100200 100300 32 680 0 100300 100400 32 680 0 600200 910010 3 430 0 600300 920010 2 5851 0 0 0 4 001 100100 100200 600 00 0 100200 100300 600 00 0 100300 100400 600 00 0 600200 910010 240 00 0 600300 920010 400 00 1 The first segment is a list of known control imported from CON The second segment is the distances The third segment is the angles The final segment is the azimuths ADD 1 107140 100140 140140 00000 1 15 310 55 310 2 107120 100120 140120 00000 1 000 000 2 0107100107140 00000 1 000 000 2 107160 100160 140160 000001 000 000 2 0107140107200 00000 1 000 000 1910040910030 1 89 59380 1 22 720 0 000 1910050910040 1 89 59380 1 9 090 0 000 2908025910050 3 0 01170 1 0 000 0 000 2 0908030908020 0 00000 2 0 000 0 000 3 910040 901004 0 0 0 000 0 000 The first 5 lines show how elongated 1 16ths 107xxx of sec 31 are stored APPENDIX B B 4 GCDB WG TRN V1 00 10262001 107140 is put in at proportion between two point IDs and the other 1 16ths are put in at intersection of two lines whose endpoint IDs are stored The 1st field describes the type of action 1 traverse proportion 2 intersection 3 add a line Intersections require 2 lines of data The 2nd f
20. is to make an AN file VERIID Input files INT IID Output file VER VERIID checks to see if a previously linked township has to be linked again after the township is readjusted VERIID prompts for a centroid distance tolerance VERIID reads an old IID file and compares the new polygon PID s with the old polygon PID s to see if they still match differences are reported in the VER file VERIID checks to see if the old centroid still falls in the new polygon and compares the distance between the old and new centroid for a polygon to see if it exceeds the centroid distance tolerance If the centroid distance tolerance is exceeded VERIID reports this in the VER file VERIID updates all the new centroids in the AN and IID file for all polygons that have the same PID s and have an old centroid that still falls in the new polygon VERIID can also be utilized to create an AN file from an existing IID file DXFW The dxfw exe program which creates Drawing Interchange Format dxf files has evolved from individual creation programs one for Least Square Analysis one for Raw Polygons one for all polygons and one for LX file conversion to a pull down menu driven program allowing the user different options for final drawing output In addition to the new menu items the ability to change text height add raw data and draw error ellipses continue to be menu driven AN2IID Input files DEF COR INT AN Output files IID
21. must be considered In addition it facilitates WinGMM s ability to automatically combine and adjust data from several townships in a region See WinGMM Users Manual Regional Adjustment of Data 2 Preparing the data files DEF SID CON and TEMP JOB WinGMM can create any file that it needs using data that is manually input by you However where this data already exists in data tables a great deal of trouble can be avoided by converting the existing data into WinGMM files The three files DEF SID and CON are required files that can be created with SQL queries TEMP JOB can be created by a batch file instead of running PROJECW printout should be made of the SID and CON files to inspect them for completeness and correctness DEF and TEMP JOB required before running INRAWW The DEF file can be created from within PROJECW Refer to Appendix B File Formats for WinGMM Data Files TEMP JOB has no more than eight characters of data inside it the name of your current project In MS DOS the contents of TEMP JOB will change each time you change to another township SID required before entering plat data INRAWW The SID file can be created and edited from within INRAWW or created through an external process customized to your existing database Refer to Appendix B File Formats for more in depth information CON required before processing coordinates GEN The CON file can be created and edited from within INRAWW or
22. new PID The single township will also now use the new PID CHZONEW Input files DEF PGC Output files LSA COR DEF The purpose of CHZONEW is to allow regional adjustment edge match across State Plane Zones CHZONEW works the same as PROJECW and any changes made will change the DEF files definitions When a menu item is selected to change CHZONEW first goes to the zone selection menus If only changing the zone select 4 When existing CHZONEW DO NOT change the project When CHZONEW is exited the plane coordinates of the selected zone are calculated The LSA and COR files are updated with those plane coordinates This allows FORMLSA to be used across zone boundaries Some townships may have to be converted back to their original zones after regional adjustment CMM2GMM Input files CMM project COR CMM project DEF Optional files CMM project LEV CMM project CHN Output files WinGMM project RAW WinGMM project CMM WinGMM project LSA If coordinates imported as control WinGMM project SD If coordinates imported as control user filename If chain file did not exist When CMM2GMM is invoked it uses a chain file or user input to determine which PID s are the end points of each survey line It then uses the CMM project COR file to inverse between these points and determine Bearing and Distances to create a project RAW file A chain file is an ASCII text file that is a list of PID s to be read from the CMM COR file for inversing
23. tei Ree tede Rs dence 4 1 BLUNDER DETECTION TOOLS AND STRATEGY 5 1 CHAPTER INTRODUCTION trennen enne 5 1 GEN easet etie cedet to tee tec eee ee i ea tes ie to eec ol tue ad ee ie bs 5 1 PROJECW MEE 5 2 INRAW W AAA AAA A AAA E 5 3 CRW RCRUM EDEN DR RU OT ERES A E CR ERI RED DR ERR 5 4 ESGMMJW deme re toi ERR ERU Et D RETREAT IESU gegen 5 5 5 7 dn ot ik 5 7 LSMINW 2 3 5 2 nn en e e e tle HR He Ae A o A A ee vn ae HT ER RD Ren 5 7 SNOOPER gu n 5 8 STRATEGIES E PERO P pm e e peer 5 8 REFINING ERROR ESTIMATPES 2 eid ede desee di 6 1 CHAPTER INTRODUCTION cuca dc eee dete deer pre eee opted egt pee e Rs 6 1 eta i 6 3 SNOOPER ieee ite A A a etude nadine HE cae a le 6 4 INRA WW ette eterne tuere sos a t Dt c Rede tip atat 6 4 SUBDIVISION OF SECTIONS APRODBW cuina dee ete sende 7 1 CHAPTER INTRODUCTION ii re Pr E veund das eves RE Fe On 7 1 SUBDIVIDING NORMAL TOWNSHIPS 0 0 cccscsssesseeseeeeeesessececseeseeseesccesessesaesaseesesseeaeassesaeeaeeaseesesaeeaseasees 7 1 SUBDIVIDING NON NORMAL TOW
24. the most likely place such blunders are located When faced with a data set where there is little or no control the user should be very wary of assigning good error estimates to survey data especially on contracted GLO surveys Lack of control in and of itself is normally sufficient evidence to suspect the quality of those surveys Fortunately because error estimates are dependent on error estimates and not just adjustments your uncertainty will be reflected Boundary transfers The current GCDB data collection process allows individual township computation with rigid coordinates from adjacent completed townships transferred in as control This leads to points of varying accuracy and uncertainty assigned no error as fixed control Thus 1885 survey data and two digitized control points used to compute the first township and known to only be reliable to 100 feet are held as perfect in the adjoining township This violates the concept of the least squares analysis being performed in the current township and almost always requires placing more flexible error estimates on the boundary and lines closing into the transferred boundary than are appropriate for those lines under normal circumstances This is an unfortunate byproduct of a rigid township boundary approach it must be recognized and dealt with but basically you have to live with this as a necessary evil in the boundary transfer regime Scenario 1 After making initial data estimates in a
25. the target townships exterior boundaries One difference is that the final coordinate results for buffer townships are not retained but will be recomputed at a later date when these townships are included in another adjoining regional adjustment Note See the description and figure under MERGING THE INDIVIDUAL TOWNSHIP DATA FORMLSA for an explanation of FIXED TARGET and BUFFER townships MERGING THE INDIVIDUAL TOWNSHIP DATA FORMLSA FORMLSA uses a command file called HOW instead of HW which controls the merging of the LSA files The HOW file is created with a text editor and should consist of a list of the townships one township per line to be included in the region Buffer townships should also be included along with the townships that their boundaries are to be fixed against Those fixed townships are placed below the word FIXED Using the below diagram an example of the HOW would look like this Italics are comments TOSSR91E Target Tp TOSSR92E Target TP TOSSR93E Target TP TOSSR94E Target TP TO6SR91E Target TP TOGSR92E Target TP TOGSR93E Target TP TO6SR94E Target TP NOREL TOSSR9SE Buffer Tp TOGSR9SE Buffer Tp TO7SRO9IE Buffer Tp TO7SR92E Buffer Tp TO7SR93E Buffer Tp TO7SR94E Buffer Tp TO7SROSE Buffer Tp FIXED TOASR90E TO4SR91E TOASR92E TOASR93E TOASR94E REGIONAL ADJUSTMENT 8 2 TO4SR95E TOSSR90E TO6SR90E TO7SR9OE TO4SR90E FIXED TOGSR9OE FIXED TO7SR9OE FIXED TO4SR91E
26. their adjustment in the previously adjusted processed region When determining what townships should be held fixed it is important to look at the number of control points and their array in a region Quality of survey data may also be a determining factor Just remember that the township files being used for the fixed boundary must be from the previously adjusted region and contain regional coordinate values The TARGET townships should be from either the individual township adjustment or the previous region s results The fixed and target townships that are from a previous regional adjustment target area have previously been merged and should merge with no problems The most common reason for an incorrect merge between them is that single adjustment townships are being used for the FIXED townships Once all the data is merged correctly with FORMLSA the data set is adjusted with LSGMMW FORMCOR is then run to parse the newly computed coordinate data back to the individual township PGC COR and GEO files The LSA file s coordinates bottom of the LSA are also updated by FORMCOR The reliabilities in the PGC files are those generated during the adjustment of the individual townships To obtain reliabilities that are common to adjacent townships FORMREL has to be run FORMREL calculates the reliabilities using all of the data surrounding a township based on user input search area and Standard Error of Unit Weight SEUW PREPARING THE INDIVIDUAL
27. township and running through the LSGMMW process you notice that 3 of your digitized control points have residuals of 240 feet or more in the ADJ file What REFINING ERROR ESTIMATES 6 2 GCDB WG TRN V1 00 10262001 should you do Scenario 2 After robusting a data set you find several E W section lines have taken most of the error perhaps 500 feet or more Unless you have reason to suspect your control the problem is probably in the survey Survey error estimates are normally rigid relative to the weighting on digitized control Thus a blunder in the survey will push the control around The proper solution is not to tighten the control error estimates but to loosen the overall survey error estimates or try to determine what lines the blunder most likely occurred and assign those individual lines a lower error estimate junk SID One tool to do this is to use PROJECW to set robusting on and then robust your survey data in LSGMMW twice on distances and evaluate the ADJ file to see if the error becomes isolated to some particular line s Robusting distances first is not a random decision but based on the fact that it is generally easier to measure distances than bearings and if an error in an individual distance is made it tends to be relatively severe and thus more easy to isolate with a least squares adjustment If no obvious blunders in distances are found robust twice on bearings If you identify data that looks bad create a
28. 00100 100140 40 070 1 500 0 11340 100140 100200 40 000 1 0 0 11340 100200 100240 40 110 1 100 0 11340 120700 100700 20 02 3 895900 0 6010 999998 The data between the 999999 and 999998 lines represent data from survey plats The fields are The 1st field is the Point Identifier for the beginning of the line The 2nd field is the Point Identifier for the ending of the line The 3rd field is distance in chain units The 4th field is the quadrant of the bearing 1 NE 2 SE The 5th field is the value of the bearing DDMMSS S format The 6th field is the Survey Identifier number SID more about the survey is listed in the SID file LSA The LSA has 5 segments Below is a shortened list 700100 653137 527 1055152 756 0 700200 653126 637 1060413 534 0 7700300 653100 770 1065747464 0 700700 653010 374 1086873 400 1 700100 700200 5280 000 0 700200 700300 5280 000 0 700300 700400 5280 000 1 0 0 0 00 001 APPENDIX B 700100 700200 00 00 0 700200 700300 00 00 0 700300 700400 00 00 1 700600 653059 258 1081552 147 0 600660 647756 151 1085478 873 0 700640 653046 086 1084201 999 0 700660 653039 534 1085526 250 1 GCDB WG TRN V1 00 10262001 The first segment is a list of known control imported from CON The second segment is the distance The third segment is the angle The fourth segment is the azimuth The fifth segment is the approximate coordinates that GENER computed for points that are not control Each line
29. 00140 200100 163100 140100 123100 100100 KKK K K K K K K KK K K K K CKW differs from GEN in that after running all possible RAW closures around sections it does not automatically calculate LINK traverses but rather asks the user if they wish to perform any additional traverses If the user answers yes CKW prompts for the point of beginning for the desired traverse It then checks the RAW file for all possible lines of data into and out of this point and gives the user a menu of all possible directions the traverse could be in It continues in this manner until the user enters a zero to signify the end point of the desired traverse has been reached When a user defined traverse in CKW closes back on the point of beginning CKW recognizes this and performs a traverse based on RAW survey data alone If a traverse does not close against the point of beginning CKW compares a geodetic traverse of the lines from RAW against coordinates in the COR file Therefore as the COR file is produced by LSGMMW CKW can only be run after LSGMMW has been completed The information regarding user defined traverses is written to the CHK in the format OK K K K K K K K K K K K KK K K K K K TRAVERSE CLOSURE REPORT SUM OF DISTANCES ALONG TRAVERSEIS 1 87 MILES CLOSURE IN NORTHING Y 2 PT CLOSURE IN EASTING 12 6 FT BLUNDER DETECTION 5 4 GCDB WG TRN V1 00 10262001 LINEAR ERROR OF CLOSURE IS 12 6 FT LINEAR ERROR OF CLOSURE AFTER
30. 1 3 EDIT RECORD INFORMATION and 1 4 DELETE RECORD INFORMATION features To list control data choose 4 CONTROL STATION MAINTENANCE 1 LIST CONTROL from INRAWW s menu You will also be presented with an opportunity to LIST control data from within INRAWW s 4 CONTROL STATION MAINTENANCE 3 EDIT CHANGE CONTROL DATA and from within INRAWW s 4 CONTROL STATION MAINTENANCE 4 DELETE DATA To list SID data choose 5 SID MAINTENANCE 1 LIST SIDS from INRAWW s menu You will also be presented with an opportunity to LIST control data from within INRAWW s 5 SID MAINTENANCE 3 EDIT SIDS and from within INRAWW s 5 SID MAINTENANCE 4 SWITCH SIDS although SWITCH SIDS does not show error estimates INRAWW EDITING EDITING OR DELETING RECORD DATA Although INRAWW will prevent you from making a wide range of data entry blunders there are just some things that get entered wrong Using INRAWW s 1 3 EDIT RECORD INFORMATION feature and INRAWW s 1 4 DELETE RECORD INFORMATION feature ensures that the changes you make are reflected properly in all the appropriate files RAW SD and LSA Both features allow you to perform these operations individually or by a block RAW DATA ENTRY 3 4 GCDB WG TRN V1 00 10262001 The appropriate files are updated after you choose to quit INRAWW ADDING TO CHANGING OR DELETING CONTROL DATA Refer to WinGMM Software User Guide INNAWW The same reasons that INRAWW should be used to ED
31. 1 D200300 200400 R03120363 5280 000 33 122 3 1 Note each line starts with a B or D indicating whether the measurement is a bearing or distance followed by the from and to point IDS The SID the input data value from the RAW file the actual adjustment from LSGMMW and the snoop value from the ADJ file Each measurement listed in the JNK file should be checked against the original source data for data entry errors STRATEGIES Following is a routine using all of the processes above Because there are so many processes that allow the user to identify errors it is left to the user to decide which ones work best for them STRATEGY TRACKING DOWN BLUNDERS IN RAWW DATA 1 Run INRAWW using a single point of control GEN LSGMMW and SNOOPER If the CHI Squared value at the bottom of the ADJ file is very high or LSGMMW fails to run you will probably want to run RAWW and input the resulting RAW LSA file to check the RAW and CON data 2 Check any measurements listed in JNK against the original source data and correct any data entry errors found If errors are found return to step 1 3 Run DXFW with coordinates read from the COR file and lines from the LSA file Import the resultant BLUNDER DETECTION 5 8 GCDB WG TRN V1 00 10262001 DXF file into any program capable of reading a DXF Note the above options cause lines to be drawn in separate colors by the source ID in the RAW and SID files 4 Copy the project SID fi
32. 10262001 SUBDIVISION OF SECTIONS APROPW CHAPTER INTRODUCTION After the adjustment process is complete it is time to subdivide the sections The goal in subdivision with PCCS was to produce coordinates of the subdivision points In WinGMM the main goal is to record the procedures used in subdividing each section and save the procedures as a future template for subsequent rerunning of the subdivision program APROPW The coordinates are temporary byproducts that change with each readjustment of the network The lines file LXN is another byproduct of APROPW The file is a list created by the user of lines and points that are not to be included in the lines file When APROPW is run it calculates the parentheticals and subdivides the sections with standard rules utilizing normal GCDB IDS Sometimes WinGMM will not recognize unusual situations and will compute incorrect procedures for creating some points but you can anticipate these situations If WinGMM recognizes that an unusual situation exists it will decide that it cannot or should not compute coordinates for the affected corner points APROPW expects you to tell it how to treat unusual situations Interpreting some plats can be complex but once you have determined what rules are used to subdivide any section then it is a simple matter of communicating those rules through APROPW s interactive prompts APROPW stores the results of your interaction in three data files IRR ADD and
33. 21E GCONW will run thru the list reading the DEF file of each project to determine which DATUM to convert to As it does a conversion it changes the DEF file DATUM to the proper DATUM If a project is in the list twice it will first convert it to one DATUM and then back to the original DATUM GCONHPW Input files COR All files created from GCONW DEF CON GEO LSA SD SID PGC AN JID LX state or region LAS NGS file State or region LOS NGS file NAD27 CON NGS file NAD83 CON NGS file Output files The existing GCONW produced files are updated based on the new datum When GCONHPW is invoked the coordinates in the existing GCONW produced files are converted either from NAD 83 to HARN or from HARN to NAD 83 When converting from NAD 27 to HARN GCONW must be run first then GCONHPW The CON file will get HARN coordinates which are labeled as such as well as NAD27 and NAD 83 coordinates produced with GCONW Unlike GCONW GCONHPW can only convert from NAD 83 to HARN or vice versa in one run In order to convert WinGMM data to HARN GCOMHP requires specific state or region HARN las and los files These files can be downloaded from the NGS web site While running GCONHPW these files have to be defined see first PROMPT below They are then saved in a file HARN INF until you elect to use a different one Note The existing project files are wiped out as the transferred data replaces it An Example of ASCII township list
34. 5 4111 Sec 006HT A 40 000 M08TO520NRO0030E 475311 6993 1160742 2464 Sec 006HT H804 ND 70 930 MO8TOS520NRO030E 475310 7549 1160745 4111 Sec 006GT L5 34 560 MO8T0520NR0030E 475317 2489 1160800 3780 Sec 006IT A 40 000 M08TO520NRO0030E 475258 6644 1160742 2087 Sec 006IT A 40 000 MOSTO520NRO0030E 475304 5981 1160750 9985 Sec 006J T 804 N D 70 930 MOSTO520NR0030E 475302 0830 1160800 3897 Sec 006J T L6 34 790 MO8T0520NR0030E 475258 8009 1160800 3698 Sec 006JT L6 34 790 MO8TO520NRO0030E 475302 0830 1160800 3897 Sec 006KT L7 35 020 MOSTO520NRO0030E 475245 6312 1160800 3637 Sec 006L T A 40 000 M08TO520NRO0030E 475245 6460 1160742 1613 Sec 006MT A 40 000 M08TO520NRO0030E 475258 6949 1160703 3712 Sec 006NT A 40 000 M08TO520NRO0030E 475258 6817 1160722 7948 Sec 006OT A 40 000 08 05203 0030 475245 6621 1160722 7720 Sec 006PT A 40 000 M08TO520NRO0030E 475245 6768 1160703 3788 LINKING 10 2 GCDB WG TRN V1 00 10262001 The AN file contains a single line for each GCDB PLSS polygon as opposed to the LLD format where multiple polygon s are represented on one line The AN file contains section number the nominal A P letter survey type survey number survey note if it exists acreage principle meridian code township range and lastly the SPC s of the centroid The AN file is the gt link between the GCDB and the LDD This is what linking is all about allowing alphanumeric parcel data to be associated with spatial data from GCDB to
35. 60 R112S06W T 1525 223 W 155022 0152S0221W R152S221W too big T109N R13E CO9NRI3E 1090N0130E R109N13E T 1092 N R 13E E09NRI3E 1092N0130E R1092N13E too big T 106N R224W C06NJ24W 1060N2240W R106N224W too big T 1013 N R 226E DOINJ66W 1011N2660E R1011N266W too big T 1002 N R 1002 E EOOSEOOE 100251002 R100281002E too Big Some townships defy standard rules like Sec 17 of T 11 N R 2 E above the river and Sec 17 of T 11 N R 2 E below the river In cases like this define a letter code that has not been used STANDARD TOWNSHIP includes townships with offset boundary lines APPENDIX A 1 GCDB WG TRN V1 00 10262001 GCDB uses a point identification scheme that assigns a six digit point identifier to each corner of a township relative to its position in the township Each point identifier has two halves the first three digits are an x coordinate and the second three are a y coordinate XxxYyy The point identifiers for the section corners are incremented up in the x and y directions west to east and south to north by the number of whole miles they are away from the southwest corner of the township This affects the hundreds place i e the first of the three digits of each point id pair XxxYyy As an example 100200 is the southwest corner of section 30 one mile north y direction of 100100 Refer to Figure A 1 Township showing ID numbering for full section corners
36. FIXED TOSSR9I1E TARGET TOG6SRO9IE TARGET TO7SRO91E BUFFER TO4SR92E FIXED TO5SR92E TARGET TO6SR92E TARGET TO7SR92E BUFFER TO4SR93E FIXED TOSSR93E TARGET TOGSR93E TARGET TO7SR93E BUFFER FORMLSA DIAGRAM GCDB WG TRN V1 00 10262001 TO4SR94E FIXED TOSSR94E TARGET TOGSR9I4E TARGET TO7SR94E BUFFER TO4SR95E FIXED TO6SR95E BUFFER TO7SRO95E BUFFER If all the townships have the correct RAW data and error estimates then the order of the HOW file is not usually important However some unusual offsets between townships may dictate the order Trial and error is the only way to find the best order in these circumstances The order of FIXED townships has not been found to be a problem NOTE Townships that each contain only a single point from the other will NOT merge at that point From the above example diagram if the townships were ordered in the HOW file like below the 700100 point of TOGSR92E will NOT merge with the 100700 point of TO7SR93E TOGSR92E TO7SR93E TOGSR93E TO7SR92E The result being 2 coordinate pairs for the same point in the regional files Even the merging of the other 2 townships does not fix the problem So townships should NEVER be listed in the HOW file in an order that will try to merge them at only a single point they must also include RAW data that is the same In some cases this requires including additional RAW data from adjacent townships in the RAW
37. GCDB must be tagged with a reference to the source of the data SID surveyor survey type field note number and date The SID number serves as that reference The SID number is placed at the end of every line of the RAW file The database will use the SID number to match line bearing dist with the source WinGMM puts that number on automatically but you must tell WinGMM what survey you are working on This is the current SID Whenever you change from one survey to another then you must switch SIDs and the new current SID will be appended to each line This new current SID is a reference to the survey that you are just about to begin entering There are two ways to switch SIDs The easiest is to hit the S key when you are being prompted for the distance bearing or GCDB ID Another way is through INRAWW s main menu 5 SID MAINTENANCE 4 SWITCH SIDS IMPORTING DATA FROM ADJACENT TOWNSHIPS IMPORTING PLAT DATA If any townships adjacent to your current township have been entered you have the option of transferring the pertinent plat data from those township boundaries and adding it to your RAW file The RAW files for these adjacent townships must be in your current directory You will be prompted for the offset to be applied to the IDS to convert them into your townships numbering scheme i e an offset of 3 will cause a 203100 in the township to the north to become 200700 in your township Also you can bring in a portion of a towns
38. IES Using WinGMM utility programs WinGMM utility programs are described in this chapter Each of these program s input and output requirements are described below with a statement of the purpose of the program To START Select the desired operation from the main Windows pull down menu SORTLSAW Input files SD LSA Output files LSA LSB SD SDB Batch mode program that will backup your existing SD and LSA files to SDB and LSB then restructures the SD and LSA files to the structured format required by LSGMMW This program need only be run if GEN reports that your file has been corrupted If such a condition exists you will be instructed to run setup COMPARW Input files COR PGC optional Output file user defined name often called OUT During the computation process one is provided with many choices that will result in different coordinate values This program will allow the user to quickly see the difference in coordinate values from two input COR files For example one may choose a certain adjustment tactic compute a COR file with LSGMMW then desire to play a what if strategy to try different weighting different control etc COMPARW would then be invoked to report the effect of the new strategy Another example could be when what if strategies are used in the subdivision process This program reports the coordinate difference for each point found in both files When different adjustment strategi
39. INATES SNOOPER of the blunder detection tools discussed so far were designed to do overall analysis of a complete data set on a township basis In the vast majority of situations these overall data sets are comprised of data from several different sources Using a vastly over simplified example it is conceivable a data set containing 50 measurements with a Root Mean Square RMS value of 5 0 and 200 measurements with a RMS of 0 0 could yield an overall RMS of 1 0 leading to a false statistical validation SNOOPER is a program developed in FORTRAN by California GCDB staff whose purpose is to provide analysis of individual sources of data based on the Source Identifier SID field of the RAW file Data from the ADJ file is gathered for each separate source and a mean actual adjustment by source is computed This is an extremely powerful tool for refining errors After computing the mean actual adjustment for each source in an overall data set SNOOPER compares each individual measurement of that source data and calculates a RMS by dividing the actual adjustment of individual measurements by the mean adjustment it just calculated Individual measurements which are adjusted more than twice the mean are written to a JNK file that looks like this B100300 100340 R03120363 N 5 3 3 12 13 1 6 B100340 100400 R03120363 5 3 OW 3 12 4 1 6 B236400 220400 R03120363 N 83 18 OW 3 47 41 1 9 B220400 200400 R03120363 N 83 18 OW 6 6 1 3
40. INING CORNERS SPECIFIED IN ADD APROPW reads the ADD file again to see if there are instructions on how to compute any more corners At this point APROPW is ignoring the functionality of the corners and ignoring rules of subdivision it just computes corners as you have specified WHAT YOU DO AUTO AUTOIRR option 4 AUTOMATIC PRELIMINARY NON STANDARD BREAKDOWN OF ALL SECTIONS First We have the option of using the AUTO AUTOIRR to give us a quick automatic creation of the entries in the IRR file This is just APROPW s first guess yet it is a very good guess and will suffice for almost all situations See Table 1 below and WinGMM Program Reference APROPW 1 Examine plat for any unusual situations Tell APROPW how to do it Table 1 Plat Unusual Situations REFINING ERROR ESTIMATES 7 4 UNUSUAL SITUATION a Offset lines Non Normal IDS act as full sec corners Refer to Fig 7 1 23 b Offset lines Junior corners need offset to line Refer to Fig 7 1 S4 c Triple sec corners 2 corners each control 1 direction Refer to Fig 7 1 S33 d Quarter corner does not exist for a 1 mile line Refer to Fig 7 2 S17 e Foreshortened section or Special Survey cuts thru sec Some corners do not exist Refer to Fig 7 2 S5 NOTE Once a corner is non computable the corners whose positions IT controls will not be computed f Exterior parentheticals are not normal Refer to Figure 7 3 g Elongated section Refer t
41. IT or DELETE plat data also applies to ADDING TO CHANGING and DELETING control data Inside INRAWW s 4 CONTROL STATION MAINTENANCE feature are 2 ADD CONTROL 3 EDIT CHANGE CONTROL DATA and 4 DELETE CONTROL The delete feature allows you to delete data individually or by a block RECORD to RECORD Error estimates can be edited by a range of line numbers or by groups of identical error estimate by 7 BLOCK EDIT CONTROL ERROR ESTIMATES The CON file will be updated only upon your request This is accomplished by choosing INRAWW s 4 CONTROL STATION MAINTENANCE 6 UPDATE CON FILE ADDING TO OR CHANGING SID DATA Refer to WinGMM Software User Guide INNAWW The same reasons that INRAWW should be used to EDIT plat data and control data also apply to ADDING and EDITING SIDs Inside INRAWW s 5 SID MAINTENANCE feature 2 ADD SIDS and 3 EDIT SIDS Your changes will be automatically written to the SID file and the SD file QUITTING THE PROGRAM CREATION OF THE NEWEST RAW SD AND LSA FILES When you choose INRAWW s 8 QUIT feature all new and changed data in the INRAWW session will be written out to the appropriate files Also as mentioned in the WinGMM Program Reference INRAWW strips out many midpoint 1 4 section corners and combines those affected lines into one mile lengths As noted above functions within INRAWW can be used to edit the SID file and the CON file These files will be updated only while you exit
42. NG ERROR ESTIMATES 7 5 GCDB WG TRN V1 00 10262001 printed for inspection verification that the proper procedures were performed in APROPW The SUB file contains a report of each irregular calculation add calculation and calculated parentheticals When errors are found in the SUB file the user will return to APROPW and edit the section s containing errors Using a text editor to view the ADD file will also point out data entry blunders that might otherwise be hard to detect AUTO INTERSECTION AND POPULATING THE NOT FILE The WinGMM software incorporates the AUTO INTERSECTION program as an automatic subroutine of the APROPW program This subroutine identifies and computes the point of intersection of all lines which haven t previously been created in the add file The LXN file is utilized and updated during AUTOI It also creates an INT file which list the newly computed intersections and the point id string of every polygon in the township This subroutine allows the user to realize significant time savings with respect to computing intersections especially if a township contains multiple special surveys AUTO INTERSECTION utilizes a unique point id naming convention with point IDs starting at 950100 950101 950102 etc The user may edit the point id numbers in the ADD file in order to satisfy point id standards for their GCDB database AUTO INTERSECTION is to be utilized as a QC step for the collection process as there should be zer
43. NOT APROPW and other yet unwritten programs in the upcoming NILS will automatically subdivide sections of finished townships using the information in IRR and ADD There are no more prompts for future users SUBDIVIDING NORMAL TOWNSHIPS A normal section has no lotting against interior lines no subdivision lines closing onto special surveys and no offset lines exterior or interior The normal section is neither foreshortened nor elongated To subdivide a normal section you will run APROPW then when the main menu appears choose 6 PROPORTION AND QUIT 3 UPDATE COR GEO amp PGC FILES WITH GENERATED STATIONS Refer to WinGMM Program Reference APROPW for step by step instructions Review the SUB file to verify that everything happened correctly Refer below to the topic INTERPRETING THE SUB FILE That is all there is to it SUBDIVIDING NON NORMAL TOWNSHIPS IRR AND ADD FILES The IRR file is populated with rules you specify using APROPW s 1 EDIT INPUT NON STANDARD SECTION BREAKDOWN INFORMATION The ADD file is populated with rules you specify in APROPW s 2 ADD EXTRA COMPUTATIONS REFINING ERROR ESTIMATES GCDB WG TRN V1 00 10262001 Figure 7 1 Figure 7 2 RI 8W RI 7W ORIGINAL PLAT IS CURRENT SEVERAL RESURVEYS LATER 40 Ac 40 Aci 40 Ac 40 Ac 20 44 6 40 4 40 1 40 1 Acres Acres Acres Acres 39 3 20 Figure 7 3WHAT IRR IS USED FOR The situations th
44. NSHIPS AND ADD FILES eere 7 1 INTERPRETING THE SUB HLE ccoo aia ad ec reete a ete e ea e ias 7 5 AUTO INTERSECTION AND POPULATING THE NOT FILE eene 7 6 USING AUTOIRR AUTO AUTOIRR AND AUTO ELONGATION ceret nennen 7 6 SUBDIVISION STRATEGIES ti Pa need iria 7 1 REGIONAL ADJUSTMENT OF DATA 5er tede Ead b eta de prae 8 1 FORMLS E M 8 1 a erede aia nal tete Eee Lene eate Hee Pete ideal dees 8 5 WINGMM OTILITIES ihe eet ettet miento 9 1 Using WinGMM utility programs nennen eene trennen trennt a tnter nnne 9 1 SORTLSAW telecom alte aieo a alte nile ede dao ba HE ela ie a 9 1 COMPAR Wenn ice ae Oe EH e Oe e t A REO a 9 1 UTM Wenas retinet ema ini a ete t dt toe eed etate 9 1 TOEXNW on a n er e e RP o RR PR EP Pets 9 1 GCDB WG TRN V1 00 10262001 GETEX ERE 9 2 NODUP cM TIENE DIS 9 2 CHGOIDS 9 2 CEHZONEN ret rte aede tetto erret te enn D hei ane e Pe aia its 9 3 CMM2OGMYNM iter einer AAA AA ERE NOSE NE NET LERRA a ali 9 3 GCONW E O AA O 9 4 GCONHEW repete n pee Pei Rete e c D er cree Woes cei 9 5 CS TUE 25 innititur Rue mh aS ire ded ut rete 9 6 QEMA Tri das 9 6
45. PW then reads the IRR file and computes all the subdivision corners including 540640 only the IRR file can specify weighted mean bearing or parallel and all corners dependent on it Now the ADD file is read again and it can compute 540700 by extending a line through 540640 only the ADD file can do intersections with non aliquot lines such as the N boundary What happens if you reenter APROPW with readjusted section corner coordinates GEN and LSGMMW will flush out all the old subdivision coordinates You resubdivide by running APROPW It will either subdivide the township automatically through 8 PROPORTION AND QUIT or it will await any more entries to the IRR and or ADD Your previous work is intact until you choose to edit it WHAT APROPW DOES The order in which calculations takes place is important COMPUTES CORNERS SPECIFIED IN ADD IF POSSIBLE APROPW reads the ADD file to see if there are any corners that it can generate using what information is available Many corners you put in the ADD file depend on corners that will later be generated through information from the IRR file There may not be enough information at this point to perform all the REFINING ERROR ESTIMATES 7 3 GCDB WG TRN V1 00 10262001 processes in the ADD file The order in which the processes are entered in the ADD file is not significant COMPUTES PARENTHETICALS When you start APROPW it reads both the COR file and the RAW file It will look for irr
46. RMLSA to create a region that includes all townships being used Insure that all townships merged correctly see 4 above D Copy your backup copy of HOW to HOW i e copy 1HW to HOW REGIONAL ADJUSTMENT 8 4 GCDB WG TRN V1 00 10262001 E Run FORMREL F Copy your backup files to their original names NOTE A batch or script routine could be used to backup and restore files 8 Run APROPW on the target townships to update township subdivisions SOLUTIONS TO COMMON MERGE PROBLEMS Merge Tolerances For FORMLSA to work correctly it is necessary to determine what would be the best merge tolerance to use A too small or large of a merge tolerance and the townships will merge with undesirable results There are several ways that this can be handled One is to test which is the best tolerance by running FORMLSA at different merge tolerances until it merges correctly Another is to always use a merge tolerance of 1500 feet and when necessary use merge control to get correct merges Any method that will get the data to merge will work FORMLSA is for creating a regional data set from the single township data and as long as the data is merged correctly it is unimportant how it is accomplished Merge Control Sometimes the quality of the RAW survey data is so poor it is almost impossible to merge townships In these cases it may become necessary to use MERGE control MERGE control is temporary control that is used to facilitate merging of townshi
47. ROTATION IS 6 STANDARD PRECISION IS 1 781 AFTER ROTATION PRECISION IS 1 16702 STATIONS IN TRAVERSE 500546 940070 940080 940090 940 100 9401 10 940120 940130 940140 940150 940160 940170 940180 940190 940200 500504 2 2K 2 K K K K K K K K K K KK OK K K K Ok In this manner the user can perform specific traverses that may not be included in the GEN file This is particularly useful in complex data sets where a problem has been localized but could be due to any of a number of individual surveys that are tied to each other such as mineral surveys Generally it is advisable to perform closed traverses of such types of surveys any time WinGMM processes indicate they may the source of problems LSGMMW Technique Viewing ADJ for analysis of the least squares adjustment LSGMMYW produces an ADJ file The ADJ file is the most valuable file for analyzing the data set It lists input measurements in the same order as the LSA file how much it adjusted residual how much you expected it to adjust error estimate and most importantly for you right now the snoop number The snoop number is the residual number divided by your error estimate Assuming error estimates are reasonable when a measurement adjusts more than three times as much as you expected there is a high probability this measurement is a blunder and LSGMMW will put asterisks to either side of the snoop number in the ADJ file The higher the snoop number the higher the prob
48. SID file specifying non Cadastral units S36970BT 0 100 5000 0 900 0 0 001 0 001 C BDY TR FROM T33NR30E C DT P lt dist type grid gt C DC 1 50 correct dist by 1 ft and 50 ppm C BT GA 0 0530 bearings are grid convert to angles error est 5 30 gt C BC 2 1040 rotate bearings counter clockwise 2 10 40 gt The 2 unit types are 1 DT distance type value consists of 1 character value Allowable values G ground E ellipsoid or P plane grid 2 BT bearing type value consists of 1 char value or 2 char value followed by a numeric value Allowable values M mean F forward G grid C compass magnetic or L local assumed Column 7 can be blank or an A convert bearings to angles If an A exists in column 7 it must be followed by an error estimate for the angles in DD MMSS HP format The error estimate can immediately follow the or have leading spaces The 2 corrections are 1 DC distance correction two numeric values The two numbers are the constant correction and the ppm correction negative value means the distance will get shorter The constant correction is in the units of the desired linear units in L A ft or meters The constant correction can immediately follow the or any number of spaces can exist Any number of spaces must exist between the constant correction and the ppm You can have a zero constant and a non zero ppm and vice versa 2 BC bearing correction one numer
49. SNOOP RMS 7 MAX DISTANCE RESIDUAL 700600 700640 OF 10 621 The overall snoop value listed here is a very important value In the vast majority of data sets it is desirable to have a snoop value between 0 5 and 1 0 here This would indicate confidence that on an overall basis the user has input valid error estimates for the distances in the data set BEARINGS The next section of the ADJ lists information regarding every bearing input consisting of From point identifier To point identifier input bearing how much that bearing was adjusted residual a snoop value and the input error estimate and looks like this MINIMUM BEARING RESIDUAL PRINTOUT 0SECONDS BEARINGS OCCUPIED SIGHTED MEASUREMENT RESIDUAL ERROR EST STATION STATION D M S D M S 700100 700200 N 0 0 0E 0 0 11 2 0 1 0 BLUNDER DETECTION 5 6 GCDB WG TRN V1 00 10262001 700200 700300 N 0 0 0 0 0 2 0 0 1 0 700300 700400 N 0 0 0E 0 0 13 2 0 1 0 repeat for every distance At the bottom of the bearing section of the ADJ file there is a listing of the average adjustment average snoop value and maximum adjustment of the entire data set that looks like this BEARING RESIDUAL RMS 0 0 12 D M S SNOOP RMS 3 MAX BEARING RESIDUAL 700700 600700 0 0 55 D M S As with distances in the vast majority of data sets it is desirable to have a snoop value between 0 5 and 1 0 here This would indicate confidence that on an overall basis the user has in
50. TOWNSHIP DATA FOR MERGING The first time that townships are merged into a region the coordinates used are from the adjustments of the individual townships Because FORMLSA uses coordinates for a search area the coordinates of adjacent township boundaries have to be close in value to each other When these values are too great the merge tolerance which determines the search area has to be so large that it causes merge problems in other areas of the region Therefore an individual township s data must meet certain requirements These requirements are easily met when each township has been correctly analyzed and has the appropriate error estimates The most important requirement is that the RAW data of a township s exterior boundaries is exactly the same data as the adjacent township s exterior boundaries This includes that the direction of lines are identical The value of error estimates of one township should be similar to the adjacent township s error estimates especially if surveyed by the same surveyor or within the same time frame using similar survey methods and instruments Small discrepancies in error estimates within a township for the interior subdivision lines have a minimal influence on the adjustment of exterior boundaries If there is a large discrepancy the interior will have too much influence on the exterior boundaries and the townships will not merge properly with FORMLSA and or the adjustment may fall outside of acceptable l
51. This lessens the effects of having to set artificial error estimates on the survey lines RAW DATA ENTRY 3 2 GCDB WG TRN V1 00 10262001 caused by importing the entire boundary It is most importantly a tool for allowing the merging of townships during FORMLSA Setup 1 The value of the error estimates of the imported control are based on the values set by PROJECW in the DEF file It is recommended if control is to be held fixed that they be set to 001 before running INRAWW 2 Append a comment line with a text editor to the CON file of the form MtxxXRxxX ffffff tttttt Where M comment line coded for merge control TxxXRxxX the adjacent township that coordinates are to be imported from ffffff the point id of the station coordinates are to be imported from tttttt the point id of the station coordinates are to be imported to CAUTION DO NOT import actual control It should already exist in both townships FORMLSA throws out control that exists in only one township If the adjacent townships PGC file is not in the same directory no control can be imported If there are changes in the adjacent township the township with merge control should be reprocessed after it 3 Before starting INRAWW delete the existing LSA and SD files then start INRAWW Select 4 CONTROL STATION MAINTENANCE Select 5 IMPORT CONTROL FROM A CON FILE and then select lt 1 gt READ ALL CONTROL IN CON FILE INRAWW reads in the coord
52. XXXXXX 00640000 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 A XX XX XXXXX 00360000 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 1 00025350 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 2 00025300 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 3 00025250 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 4 X 00021670 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 5 3 00034560 ID 079 01 06 48 00 10010600 000000 08 0030 0520N 006 L 6 00034790 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 L 7 00035020 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 006 H 804 XXXX 00070930 D ID 079 01 06 48 00 10010600 The first two lines contain a portion of LLD for two sections that are all aliquot with no special surveys or lots in them This represents an example of LLD for a section in its simplest form Notice the sixteen X s they represent the sixteen portions of a normal section broken down to the one sixteenth or forty acre parcel level The rest of the lines represent a section that contains some forty acre aliquot parcels some lots and a special survey HES 804 To understand where the sixteen meaningless X s fall in a section an
53. ability of blunder but to maintain consistent format of the ADJ file snoop numbers can never be higher than 9 9 Low snoop numbers can be an indication of poor error estimates and can result in statistically invalid data adjustment Optimal snoop numbers are between 0 5 and 1 0 but generally snoop numbers up to 3 0 are not considered cause for undue concern The ADJ file starts by listing some very important information regarding the least squares adjustment of the data set HEADER INFORMATION Information regarding the overall data set including the datum the data was processed in coordinate units projection network average elevation used number of relevant measurements input and generated and a multiplier needed to derive a 95 positional confidence of the final coordinates error values RESULTS OF ADJUSTMENT A listing of all point identifiers their adjusted coordinates and information regarding the statistical quality of each point based on the least squares adjustment Following this section of overall information the ADJ file contains very important information regarding individual measurements in the data set CONTROL POINT COORDINATES The control portion of ADJ lists point identifiers how much the control point was adjusted residual the input estimated quality error estimate and a snoop value in northing and easting for each control point used and looks like this CONTROL POINT COORDINATES BLUNDER DETECTION
54. agnitude so as to cause significant effect on the adjustment of the overall data set These significant errors or blunders can be introduced to the WinGMM process a number of ways We might have transposed or otherwise incorrectly entered record survey information from the plat We may have assigned an incorrect Point Identifier to an otherwise valid control coordinate These types of errors can be corrected if identified by editing the incorrect data However not all blunders are so easily addressed In some cases we may have entered the data correctly from the survey plat but that data is inconsistent geometrically with other measurements Most of the WinGMM programs offer clues to finding data that was keyed in wrong or was bad in the first place This chapter lists the programs you can run and some strategies you will find useful in finding and dealing with blunders In most cases there will be several sources of survey and control data in a township data set These situations are the most complex data sets to analyze and there is an advantage to analyzing the survey data alone The procedure to accomplish this is to import only one control point from CON forcing GEN and LSGMMW to perform an adjustment based only on plat data The GEN and ADJ files can then be reviewed for analysis of this plat only processing The plat data can also be checked for data entry blunders and general quality with the programs LSMINW RAWW and CKW as well as the
55. an external process customized to your existing control database Sometimes there are two sources different coordinate values for the same corner and one of the lines should be commented out so WinGMM will not use it in the adjustment Refer to WinGMM Program Reference INRAWW 7 Control Station Maintenance 3 Import Control from a CON file In short if you put a non space character in the first column of a line in the CON file then WinGMM interprets that line to be a comment to the user not a piece of valid data to use in the adjustment Merge control where coordinates from adjacent townships are used to assist in the merging of townships during regional processing may also be coded in the CON on a ABSTRACTION 2 3 GCDB WG TRN V1 00 10262001 comment line See Regional Adjustment of Data RUN PROJECW TO STORE DEFAULTS if there is no DEF file or TEMP JOB file The DEF file and TEMP JOB must exist in the township subdirectory Running PROJECW to define the project name will result in the creation of those files GCONW and GCONHPW NAD Datum Conversions GCONW uses National Geodetic Survey NGS s NADCON NAD27 to NAD83 and NAD83 to NAD27 geodetic program which has been adapted to WinGMM GCONW requires NGS files CONUS LAS and CONUS LOS which provide data for the NAD27 to NAD83 and NAD83 to NAD27 conversion GCONHPW is for conversions to HARN from NAD83 or NAD83 to HARN Operation for GCONHPW is the same as for GCONW excep
56. are easily detected what WinGMM literature refers to as automatic blunder detection Once data entry mistakes are corrected it is up to the user to determine why certain areas do not achieve satisfactory results A conceptualization of the network adjustment process blended with a sense of cadastral history and data analysis is used to focus on the reason an area doesn t fit Users can easily revise assumptions about the quality of certain surveys or control points and then rerun the adjustment The result is successively better final results and more importantly a much clearer idea of how reliable the source data is and consequently how reliable the computed WinGMM Technical Reference Manual doc INTRODUCTION 1 3 GCDB WG TRN V1 00 10262001 coordinate values are Not only will WinGMM present a definite idea of the reliability of the data processed but also the results will be expressed in standard statistical convention The GCDB data model has been designed to accommodate the crucial data provided by WinGMM and any other true least squares adjustment Refer to GCDB s draft Baseline Data Collection Model Version 1 3 03 27 90 Attribute Numbers 9044 9048 9150 and 9152 EASE OF MAINTENANCE WinGMM remembers the interaction the previous user had with the data This data makes upgrading GCDB very simple Any new data that enters the database is tagged with assumptions as to how good it is This new data replaces the data that resided ther
57. asurements that shows the relative quality of error estimates on these data types is given As with CHI Squared a SNOOP value of 1 0 is optimal with a range of 0 7 2 5 being consider acceptable Unacceptable RMS and SNOOP numbers may be indicative of blunders in data but if the plat checks with the data in the RAW file and the residuals and snoop numbers are still too high or low the associated error estimates for those measurements should be refined The CHI SQUARED TEST ON ANALYSIS tests the standard error of unit weight at 05 95 two tailed confidence level for the overall data set If all individual RMS values are acceptable and CHI Squared passes you probably have no large blunders and you did a very good job at error estimation This is a very rigid statistical test For a further discussion of a Chi Squared test refer to a statistics text If you are sure all blunders have been handled RMS values for distances bearings and control are acceptable and your data set fails CHI squared but is within the 0 7 2 5 range do not spend time trying to refine error estimates Spending a lot of time tweaking error estimates to make the chi squared test pass is unnecessary as it will make little difference in the final coordinates computed SNOOPER The LSGMMW discussion above relates to the overall data set analysis In most cases WinGMM processing involves data from several different sources The program SNOOPER was developed by the BLM Cali
58. at pertain to the IRR file Normal rules are used for subdivisions involving aliquot corners that have non normal GCDB IDS Section corners on offset lines and triple section corner situations apply here See Figure 7 1 above REFINING ERROR ESTIMATES 7 2 GCDB WG TRN V1 00 10262001 Normal GCDB IDS that should not be computed using normal rules Corners that do not exist foreshortened sections and corners that should be computed using a specific method are the two main examples See Sections 5 and 17 in Figure 7 2 above Remember APROPW will not compute coordinates for a point that already has coordinates Normal rules are used for corners that have normal GCDB IDS but must be put in at proportions that are not discernable from the RAW file Examples Sections that are lotted against an offset interior line Parenthetical distances where section centerlines are not at geometric midpoint are computed correctly by Version 1 00 of WinGMM See Figure 7 3 above WHAT ADD IS USED FOR remaining situations The ADD file stores the results of a GCDB customized coordinate geometry COGO It can compute corners at a specified or proportioned distance and along a specified or computed bearing such as parallel or weighted mean bearing It can compute intersections It can compute either geodetically or it can treat the data as if it is on a plane If you assign a point ID like 620640 or 440440 to a corner then that point will
59. ates print adjusted grid brgs dists update COR file TOSNR14W Project name 14 Meridian AZ State designation 12 UTM zone number not applicable to WinGMM 1 not applicable to WinGMM N N Y lt ZZZ SID Below is a shortened example of a SID file created by an Oracle query 55071 1 000 9999 0 1800 0 30 000 30 000 C GLO 11 DEC 1872 O FOREMAN 55905 1 000 9000 0 1600 0 30 000 30 000 C GLO 04 1880 VULTURE CITY C MINERALS 922151 1 000 7000 0 1200 0 30 000 30 000 C GLO 05 JUL 1908 52511 112400 APPENDIX GCDB WG TRN V1 00 10262001 For the lines starting with S The 1st field in Column 1 identifies SID data S The 2nd field is the SID number and must start in the 2nd column The 3rd field is the Distance Error Estimate Constant ft units The 4th field is the Distance Error Estimate PPM no units The 5th field is the Bearing Error Estimate Constant second units The 6th and 7th fields are obsolete Lines following the SID data are comment lines and start with the letter C In the BLM the standard for the first comment line after each S line is The 1st field in Column 1 identifies line as a Comment line C The 2nd field is Source Agency 3 4 character abbreviation i e BLM USFS The 3rd field is the Survey Type original D dependant resurvey etc The 4th field is the Surveyor s name or MS number and Volume number Next is an entry in a
60. batch mode there are no interactive prompts RPLOY reads the RAW file and creates polygonzs from the abstracted survey measurements and annotates the polygons as S standard I inny or O outy A standard RPO polygon is a section or fractional section with no special surveys in it An inny RPO polygon is a polygon which encloses a special survey of some type HES Tract Mineral Survey etc abstracted lots in normal sections are not innyzs An outy RPO polygon is a remainder polygon created when a special survey invades or extends into another section and does not enclose the entire special survey LLD Input files COR DEF INT LOT RAW RPO SID Output files IID AN LLD runs in batch mode there are no interactive prompts LLD is the most important and complicated of the suite of linking programs The IID file LLD creates is large and cumbersome to edit manually LLD reads the files indicated above and for each polygon computes a centroid and post adjustment area LLD LINKING 10 3 GCDB WG TRN V1 00 10262001 then utilizes the area and PID s for the polygon to match them with the appropriate corresponding data in the other files it reads All of the matched data is parsed out to the IID file to create a parcel report of each polygon with information that is needed for that polygon LLD also includes a statistical type of report at the end of the IID file regarding each section and the entire township The last thing LLD does
61. begin with when the data conflicts it is survey error estimates that need to be refined The following is a discussion of some of the specific WinGMM programs that can be used to refine survey data error estimates LSGMMW The summary at the bottom of the ADJ file produced by LSGMMW looks like STANDARD ERROR OF UNIT WEIGHT IS 933 WITH 140 DEGREES OF FREEDOM CHI SQUARED TEST ON ANALYSIS REFINING ERROR ESTIMATES 6 3 GCDB WG TRN V1 00 10262001 748 lt 933 lt 1 208 LOW HIGH PASSES AT THE 5 SIGNIFICANCE LEVEL The STANDARD ERROR OF UNIT WEIGHT SEUW is a special number If your network adjusted exactly as much as you estimated this number would be equal to 1 000 If the network adjusted more than you estimated then this number will be greater than 1 On the other hand if the data adjusted less than you expected this value will be less than 1 A general rule of thumb is if the SEUW is a less than 0 7 your error estimates are probably too loose and if it is greater than 2 5 your estimates are probably too tight or there may be blunders in your data A large value can be a good indicator of the presence of large blunders somewhere in the data Only after any blunders have been removed is SEUW a valid indicator of your overall error estimation The CHI Squared test is dependent on the Root Mean Squared RMS values of control distances and bearings contained in the ADJ file In addition a SNOOP number for all three types of me
62. between The order of the chain file determines the inverse Each chain must end in a zero line Example Chain file 100100 100140 100200 and intervening stations with WinGMM PIDs UTILITIES 9 3 GCDB WG TRN V1 00 10262001 100640 100700 0 200100 200140 and intervening stations with WinGMM PIDs 200640 200700 0 etc thru all stations with WinGMM PIDs GCONW Input files COR DEF CON CONUS LAS NGS file CONUS LOS NGS file NAD27 CON NGS file NAD83 CON NGS file Optional files GEO If GEO is missing it will be built from CON LSA SD SID PGC AN JID LX ASCII list of townships Output files The existing WinGMM Input and Optional files are updated based on the new datum When GCONW is invoked the coordinates in the existing WinGMM Input and Optional files are converted either from NAD 27 to NAD 83 or from NAD 83 to NAD 27 GCONW reads the DEF file to determine which way to go GCONW input is either form the keyboard or from the optional ASCII list of townships The CON file will get both NAD27 and NAD 83 coordinates which are labeled as such Projects can go from NAD 27 to NAD 83 and others can go from NAD 83 to NAD 27 in the same run Note The existing project files are wiped out as the transferred data replaces it An Example of ASCII township list TO3NR17E TO3NR18E TO3NR19E TO3NR20E UTILITIES 9 4 GCDB WG TRN V1 00 10262001 TO3NR21E TO4NR17E TO4NR18E TO4NR19E TO4NR20E TO4NR
63. calized and become much easier to identify Note the output ADJ file is appended to not overwritten when robusting is performed This allows the user to see what steps were taken in robusting a data set and analyze the effect of each action Finally robusting is meant to serve as a blunder detection tool is not an acceptable process for least squares adjustments and must be turned off for the final LSGMMW of a data set INRAWW Technique Viewing distances in different units of measure The RAW file stores all distances in chains If the plat has distances in feet then the distances have to be converted to a common unit in order to check them Fortunately INRAWW is capable of displaying RAW data in chains feet or meters Example a mineral lode line is 612 15 feet across the end line according to the plat INRAWW will normally list this line in chains and you read 9 275 chains You can change the distance units to feet through INRAWW s 7 CHANGE DISTANCE UNITS 2 FEET then listing the same mineral lode line will produce the distance in feet 621 15 feet instead of 9 275 chains Here is where you can detect the mistake the actual plat distance should be 612 15 feet not 621 15 In areas where feet were used on the plat you can print out the RAW in the correct units using INRAWW s 1 LIST RECORD INFORMATION in conjunction with your operating system s facility for printing out scrolled data You can press Ctrl P to print whatever
64. combined with survey data indicates a much better confidence level than that By using the procedure outlined in the chapter on Blunder Detection WinGMM programs will almost always provide a preponderance of evidence to help you make a decision If not you should presume the control is good and proceed accordingly Surveys Many older surveys and occasionally more recent surveys contain field blunders In addition there are periods in history in which fraudulent surveys are known to have been performed under the contracting system throughout the western United States In fact the unacceptably high incidence of poor quality surveys was the main impetus behind abandoning the contracting system of performing PLSS surveys in 1910 Some examples of blunders which you may encounter are discrepancies between the notes and the plat individual measurement blunders fictitious closings invalid basis of bearing ties and lines not actually run in the field or reported random and true lines that were in fact stubbed out These types of errors can be quite large and are often in areas where for obvious reason little or no control has been identified Without adequate control or significant additional information it is very hard to identify all these blunders Again you may not be able to justify going to the field to verify suspected blunders in the survey Where control is available WinGMM s LSGMMW analysis process will usually assist you in determining
65. complished manually REFINING ERROR ESTIMATES GCDB WG TRN V1 00 10262001 REGIONAL ADJUSTMENT OF DATA FORMLSA Data collection in a township by township piece by piece approach complete with township boundary transfers is a convenient way to collect data It does however lead to buildup of systematic error in results In order to eliminate that systematic error and to define a more meaningful reliability a larger data set should be analyzed The ideal situation is to readjust all data each time changes are made to the data set but this may end up with some management problems due to the size of the generated data sets Someday we may have computers powerful enough to allow all of a principle meridian to be run at once FORMLSA allows one to merge LSA township files into one correctly merged data set for simultaneous analysis The purpose of merging the data from the individual townships into a region is to obtain edge match and get the best possible coordinate values from the least squares adjustment By merging townships it increases the amount of redundancy on township exterior boundaries Edge match between regions is obtained by including townships from a previously processed region in the new region These are called FIXED townships The boundaries of the fixed townships are held as FIXED CONTROL This means the edges of these townships will not adjust in the new region and will retain the regionally adjusted coordinate values from
66. component of that SID If no change is desired for a particular component of the SID the user accepts the existing value by simply pressing return Upon exit from INRAWW the user is ready to complete the cycle by running GEN and LSGMMW and then perform analysis of the results again To change error estimates for a single individual measurement blunder it will be necessary to place a unique error estimate on that individual measurement This is a two step process of editing the SID value in the RAW file and creating a corresponding error estimate in the SID file To edit the SID value in RAW choose the RECORD DATA MAINTENANCE and EDIT RECORD INFORMATION options in INRAWW Locate the target record s by using the listing function and edit their SID value Next use the SID MAINTENANCE and EDIT SIDS options to create a new SID Many users choose to use the original SID value to indicate the original source So a record that originally had a SID of 1893 might be given a SID value of 1893J If an error is made in this process and a corresponding SID from RAW is not found in the SID file error estimates are assigned based on default error estimates set in PROJECW and a SID is appended to the bottom of the existing SID file indicating this happened Any SID value from the SID file that is not found in the RAW file has no effect on the adjustment nor is this situation identified in any output file REFINING ERROR ESTIMATES 6 5 GCDB WG TRN V1 00
67. conversion of PCCS data into WinGMM standards CHGIDS Input files All project files defined by CHGIDS CFG Output files All project files defined by CHGIDS CFG This is a simple program to allow you to globally change GCDB IDs on the default project s files It uses a file called CHGIDS CFG to define valid file extensions to check It would be wasteful if not destructive to change things in binary files When you first invoke CHGIDS without a CHGIDS CFG in the current directory it will return a file error but then will create a default file In most cases this file will be adequate however you may edit it to add any special files you may generate or delete ones you do not want to change WARNING This program changes PIDs with no test for existing or incorrect PIDs therefore be sure to backup your job before using it and check it afterward The program is mouse driven but you can also navigate with the tab and enter keys CHGIDS will skip files whose extensions are not in the CHGIDS CFG file The program will only change PIDS that are at the beginning of a line or at the end of a line or have a leading or trailing space or in an LXN file are located at proper multiples of 6 characters along the line of IDs UTILITIES 9 2 GCDB WG TRN V1 00 10262001 CAUTION NEVER use CHGIDS on regional files Change them at the single township level the next time that township is included in a regional adjustment it will use the
68. ct called Legal Land Description LLD The LLD file contains basic land information regarding the polygons found in a given township The BLM has other title information tied to the LLD such as information regarding mining claims status of the land and so on All of this information including LLD will be used to populate LR2000 GCDB is the PLSS spatial component of LR2000 basically the geographic coordinates of corners and how the lines between the geographic coordinates should be connected Note that some of the GCDB data is attribute information that like LLD is not of a spatial nature The PLSS coordinates and lines from GCDB are used to define polygons for the PLSS The correlation between the LLD and GCDB will give LR2000 the gt link to a spatial product needed to determine where the LR2000 attribute information is located in the United States and enable graphical depiction of this data hence the term linking UNDERSTANDING THE PORTION OF LLD NECESSARY FOR LINKING It is not necessary to have a complete understanding of LR2000 and subsequently LLD to complete the linking process It is only necessary to know the parts of LLD that need to be correlated to GCDB polygons to support LR2000 i e LLD polygon data Below is a sample of a portion of LLD followed by an attempt at explaining it 000000 08 0030E 0520N 010 A XXXXXXXXXXXXXXXX 00640000 ID 079 01 06 48 00 10010600 000000 08 0030E 0520N 011 A XXXXXXXXXX
69. d to facilitate their use in the linking process it is necessary to decipher them with the sixteen letters A P A for the first X and P for the last The following diagram Figure 10 1 depicts which aliquot part of a section the X s fall in this is referred to as a nominal location LINKING 10 1 GCDB WG TRN V1 00 10262001 FIGURE 10 1 COMBINING GCDB AND LLD WITH THE AN FILE The final product of the linking process is the AN file This file contains a centroid or area point for GCDB generated polygons along with part of the information found in LLD A centroid is a point node that is located within a polygon It is not necessary for the centroid to be centrally located within a polygon it is only necessary for the centroid to fall somewhere completely in the polygon Below is an example of an AN file for section 6 of the same township as the previous example of LLD above Sec 006AT L1 25 350 MOSTOS520NR0030E 475322 3578 1160703 3912 Sec 006BT L2 25 300 MO8TOS20NRO0030E 475322 3573 1160722 8508 Sec 006CT A 40 000 M08TO520NRO0030E 475311 7160 1160722 8250 Sec 006DT A 40 000 MO8TOS520NRO0030E 475311 7212 1160703 3765 Sec 006ET L3 25 250 M08TO520NRO0030E 475322 3723 1160742 3046 Sec 006FT L4 21 670 MO8T0520NR0030E 475322 3739 1160800 4082 Sec 006GT 804 ND 70 930 MO8TOS20NRO030E 475311 6426 1160800 3922 Sec 006GT L5 34 560 MO8TO520NRO030E 475311 6426 1160800 3922 Sec 006HT A 40 000 M08TO520NRO0030E 475310 7549 116074
70. data do not support each other some professional judgment is required to determine where the errors are Properly interpreting results in these cases requires knowledge about plat data and control data The more you know about both types of data the easier your judgment will be The question is where is the corner In many cases you can t be sure unless someone goes to the field and verifies the true location of the corner If a single digitized control point is way off and a recent survey has to bend a great deal to fit it in you might conclude the control coordinates are in error and you can comment out that piece of control Be aware that eliminating control coordinates is tantamount to saying the plat data is correct Again unless you have intimate knowledge of the survey or control data it is difficult to make such a statement Furthermore by eliminating the control point there is no longer anything to indicate there may be uncertainty and error estimates on the coordinates generated by LSGMMW will not reflect this In a similar situation where you have reason to doubt the accuracy of the survey such as a survey performed prior to 1900 you may choose to loosen the survey data error estimates to stop excessive movement of the control point The most difficult decision in these cases is determining where the errors in the survey data might be In the case of a section corner are there errors in all lines into and out of the control point or
71. data of each This problem occurs even with control on the point 8 3 REGIONAL ADJUSTMENT GCDB WG TRN V1 00 10262001 Adjusting a Region 1 A project name for the combined project must be defined and set to be the current job 2 Create the HOW file 3 Run the program FORMLSA FORMLSA identifies the common lines by coordinates and assumes all boundary checks have been completed FORMLSA merges data from the individual LSA and SD files Using CMM s COMBIN concept of if it is control in one and unknown in another it becomes an unknown because it was only held to keep coordinates consistent with some previous work This is especially true with coordinates imported from an adjacent township which is done to give coordinates to a township that may not have control at all FORMLSA will properly recognize these imported points as NOT control the regional adjustment will be performed with only true control Since the error estimates for each township are similar the order of the merge defined in the HOW file is not restricted FORMLSA can then use either townships error estimates in the SD files and the adjustment will give satisfactory results FORMLSA also creates a file called region MAT that is read by FORMCOR for creating the individual township COR files region MAT tells as an example what 700142 are in the combined COR file FORMCOR thus also does not worry about offsets etc as everything is defined by region MAT 4 Run
72. data or in the plat data perhaps requires extensive research and analysis The data of the PLSS must be examined using various reliability values for the data to determine quality results This may involve knowledge of the work quality of the surveyors by comparing the original work with more recent surveys This comparison can result in quite accurate estimates of the quality of the original work In most cases the final determination is that credence should be given to all the measurements but in different degrees Who or what has the time to do an extensive mathematical analysis of every possible combination of data The process of comparing multiple error estimates with multiple line segments is a daunting task and these computations can only be accomplished effectively with computers WinGMM USES THE TECHNIQUE OF LEAST SQUARES ANALYSIS The technique of least squares analysis is used by the scientific community to analyze complex data sets Many students were exposed to the concept when they were attending college but its application was not needed on the linear data sets that surveyors normally encounter Least squares analysis is well suited to the task of data comparisons from a variety of survey sources Every bearing distance and control coordinate is considered by WinGMM to be a measurement and is assumed to have some error associated with that measurement Each piece of data is tagged with the users first estimations concerning the amount
73. e normal section with nominal IDs and put the offset IDs on corners for the adjacent section to indicate the relative position from the normal corner There is no need to indicate which side the corner controls AUTOIRR can determine that from connectivity Triple Section Corners see figure A 5 Triple section corners are common for completion surveys There is one corner that is a full section corner for the senior section One of the other two corners is a full section corner to the section to the side of the senior section but is only a partial section corner for the section corner on the diagonal from the senior section it controls proportions only along the line that closes into the senior section In Section 20 of figure A 5 corner IDs 200300 200302 and 202300 are perceived by us and by the software to be of section corner status WinGMM s AUTOIRR function deduces the proper relationship of each of these 200300 only to the SW 200302 a full corner to the NW but only controlling to the North on Sec 20 and so on Using 200300 as the NE corner of Sec 30 means that there will not necessarily need to be an entry in the IRR file for Sec 30 Elongated Sections see figure A 6 Elongated sections are special cases of rectangular surveys The corners should generally follow the recommended rules listed above but when the obvious values are exhausted it does no harm to use other values Preferred values are 103 104 107 108
74. e COR file and lines from the LXN file DXFW is an invaluable tool for determining if APROPW correctly created all polygons in a township by using coordinates from the COR file and lines from the LXN file After a region has been merged with FORMLSA DXFW can be used to create a DXF file using coordinates and lines from the LSA file Then the region can be graphically inspected for a proper merge of township boundaries LSMINW Technique Track down blunders in plat data The program LSMINW performs a least squares adjustment using a single control point This allows statistical analysis based solely on information in the RAW file As most surveys are required to close within certain limits use of low error estimates can identify extremely minor errors in data entry LSMINW is also useful in identifying and handling platting blunders where required closures were not met or there were discrepancies between the plat and the notes Finally introduction of multiple control coordinates in BLUNDER DETECTION 5 7 GCDB WG TRN V1 00 10262001 LSGMMW allows us to identify errors in the survey not reflected by the plat resulting in the ability to generate truly useful error estimates of the survey data and the geographical positions generated from that data For the purpose of this analysis LSMINW outputs the MIN file containing identical information as in the ADJ file with the exception of the sections on RESULTS OF ADJUSTMENT and CONTROL POINT COORD
75. e do exist they must have point ID s in multiples of 5 for example if the 1 4 corner is 140400 and the W 1 16th is 120400 the W 1 16 80 must be 115400 2 The point IDS generated by AUTO ELONGATION deviate from the standard point ID scheme they are all multiples of 5 for example a W 1 16 usually called 120400 might be given an ID of 130400 Refer to WinGMM Program Reference APROPW SUBDIVISION STRATEGIES As stated earlier the WinGMM software has been designed to create a template for the subdivision of each township The template is the combination of IRR ADD and NOT files and once created will automatically subdivide the township on subsequent runs of the program APROPW It is important to keep in mind a few collection concepts when creating the initial template For while the perceived goal is to recreate digitally the official survey record integration into LR2000 is equally important and sometimes these goals are conflicting For example refer to attribution examples when the official record identifies lotting against mineral surveys the polygons created by WinGMM should match the record LR2000 always deals in the concept of nominal parcels and polygons are either all or parts of nominal parcels Nominal lines are the lines that segregate the aliquot parts of any section 1 16th 1 4 and section lines For the survey record those aliquot lines do not exist within mineral surveys So in the example described the strategy for cr
76. e prefixed by odd numbers for example 807 Right and left banks are determined as you look downstream Lakes will have only one segment identifier prefix Each meander line should have a segment identifier 1 e right bank meanders informative traverse lakes islands and fixed boundary The last three digits suffix of the segment identifier for each angle point on the meander line will begin 000 after the meander intersects the township or section line and be numbered sequentially downstream 002 004 etc Non boundary points Monuments of known position and not part of the land net such as triangulation stations and U S Mineral Monuments are sometimes given PIDs that start with 99 For each XxxYyy Xxx 100 710 Rectangular 711 799 Boundaries with Mileposts 800 836 Meanders 837 899 Tracts 900 999 Mineral Surveys Homestead Entries etc Yyy increments by tens sequentially along the survey Groups of similar surveys may have one segment identifier prefix SUMMARY Segment Identifiers APPENDIX A A 8 GCDB WG TRN V1 00 10262001 SID SUFFIX NAMING CONVENTIONS SID Survey Identifier is a reference to a particular survey dates surveyor volume page etc Each line in the RAW file must have a SID as part of GCDB s data base requirements WinGMM also uses the SID to more fully automate the assignment of error estimates Experience has shown that the SID can be embellished to accomplish mo
77. e previously There is little more interaction WinGMM readjusts the geometry of the plat data and then re subdivides the sections automatically Once data for a contiguous set of townships has been collected blunders removed from RAW data and error estimates refined they can be combined into a regional set of data This provides a means of maintaining a seamless data set The boundaries of adjacent townships will have exact coordinate matches for every corner After the region is adjusted each individual township data set is updated using regional coordinates Then they are re subdivided by using the instructions recorded during the data collection Using WinGMM the individual land parcels can then be linked to the BLM s Legacy inventory of legal land descriptions LLD This process attributes each polygon created by WinGMM with the legal land description as collected from the BLM s Master Title Plats and survey plats COORDINATE GEOMETRY IS USED TO FURTHER DIVIDE THE MEASUREMENT NETWORK The survey lines and points that comprise the survey plat do not always completely describe land parcels Another process using coordinate geometry is used to break land units into smaller pieces as prescribed by deed descriptions or normal subdivision rules In PLSS this is known as section subdivision Other survey systems have concepts such as an offset line i e a 25 foot strip along the western lot line Section subdivision occurs mostly with und
78. eating the subdivision template would be to identify the lots the mineral survey and the nominal lines Currently the WinGMM software has limited functionality that respect to recreating the correct template for all intersection situations The options for general intersections include either bearing input or bearing defined by two point ids excepting the subroutines for editing center of section and center of quarter sections Those subroutines have the options of projecting lines which are parallel to a line defined by point ids or weighted mean of two lines defines by point ids With general intersection parallel or weighted mean bearings methods are accomplished either by using CSTUF to determine the post adjustment bearing which must be recalculated subsequent to each adjustment or by using the record bearing from the plat which is not correct due to adjustment Creating the template for elongated sections has become automated wizard in It was formerly a manual process of inputting additional computations Often each user kept a generic add for the most frequently occurring elongated situations and edited to get the correct distances in the file With the automated function the prompting cycle leads the user through the necessary parameters but the user is forced to follow the point id naming convention of the wizard If the user requirements demand a different point id naming convention for the elongated 1 16ths then the process must be ac
79. efer to WinGMM Program Reference INNAWW Chose Edit Input Edit Record data INRAWW If no RAW file has been established then INRAWW will place you at point 100100 and prompt you for the distance of the line going Northerly along the W boundary of your township It is at this time that you should key S to get the prompting for defining the default SID number The purpose of the default SID is to save you from having to type the SID number after each line of data Another choice you have in this prompting cycle is to type Q which will quit the prompting cycle and return you to the main INNAWW menu If you didn t quit then you will answer the prompt for distance then the prompt for bearing then the prompt for the NEXT ID and the one at the other end of the line Remember if you answer the prompt with 640 then INRAWW will apply the values of line 100100 100140 to each half mile leg up to 100640 and you will then put in the data for 100640 100660 CONTINUING THE INPUT OF RECTANGULAR PLAT DATA RAW EXISTS RAW DATA ENTRY 3 1 GCDB WG TRN V1 00 10262001 If the RAW file exists when you start up INRAWW then you will be brought to the main menu Choose 2 RETURN TO INPUT OF CARDINAL LINES to input more section line data You must then indicate your starting corner GCDB ID PUTTING IN DATA FROM A DIFFERENT SURVEY TIME TO SWITCH SIDS Often townships are comprised of data from different surveys Each survey line entered into
80. egular distances on lines closing into the township lines i e the existence of xxx120 xxx660 120yyy 660yyy IDS in the RAW file APROPW will then use these parenthetical distances to compute the proportion of the 1 16ths on the section centerline going into the boundary READS IRR FILE The IRR if it exists contains the data where you specified which corners not to compute which corners to use to control the subdivision and where to put proportioned corners COMPUTES REMAINING CENTER 1 4s AII center 1 4s that were not in the RAW file or the ADD file and not specifically excluded by you through the IRR file will get computed at intersection of center of section lines COMPUTES REMAINING EXTERIOR 1 16ths All 1 16ths along section lines that were not in the RAW file or the ADD file or not specifically excluded by you through the IRR file will get computed at midpoint COMPUTES REMAINING CENTERLINE OF SECTION 1 16ths 1 16ths along the centerline of sections that were not in the RAW file or the ADD file and not specifically excluded by you through the IRR file will get computed at midpoint or at the proportion that was computed from the parenthetical distances COMPUTES REMAINING 1 16ths All NE SE SW and NW 1 16ths that were not in the RAW file or the ADD file or not specifically excluded by you through the IRR file will get computed at intersection of lines between the appropriate 1 16th corners COMPUTES REMA
81. error of unit weight If you are pessimistic in estimation or you have very few redundant measurements a very small standard error of unit weight will result Standard error of adjusted coordinates these are the least squares error estimates of adjusting N E coordinates They are a function of proximity to existing control points The statistical significance of these quantities is that if you went and made the same measurements with the same instrument using the same APPENDIX C C 2 GCDB WG TRN V1 00 10262001 procedures you would have a one sigma 68 3 confidence chance of being within plus or minus the standard error of the first solution s coordinate It has nothing to do with additional traverse legs and readjustment comparing to someone else s coordinates or evaluating retracement evidence State Plane Coordinates projections which uniquely relates a geodetic position latitude longitude to a plane coordinate pair N E The relation is truly a one to one correspondence for a unique state plane coordinate pair there is only one latitude longitude pair and vice versa The two types of projections that exist are Lambert a conic projection for states elongated east west and Mercator a cylindrical projection for states elongated north south The size of a zone was limited by defining a state plane distance will not differ from its geodetic counterpart by 1 10000 of the distance Thus larger states are covered by more than zone S
82. ers to control data and the error estimates in the SID and CON file INRAWW has many features that are appropriate during data entry Those features in the order we will explore them are Adding plat data for rectangular surveys beginning continuing Switching SIDs to indicate another survey is being input Importing plat data from boundaries of adjacent townships Importing coordinates from boundaries of adjacent townships optional Adding plat data from special surveys and complex rectangular surveys Importing known control coordinates from the CON file Listing data on the screen to review and verify file content of RAW CON SID Editing or deleting record data Adding to changing or deleting control data Adding to or changing SID data Creating approximate coordinates of each point Provide a traverse closure report Updating CON RAW SD and LSA files We will start with just getting rectangular plat data into the computer then focus on the other INNAWW features you will need to know about We assume that files SID and DEF already contain data values that are correct to our best knowledge Files such as CON LSA SD and RAW need not exist at this point If DEF does not exist run PROJECW and answer the prompts If SID does not exist run INRAWW 5 SID Maintenance 2 Add SIDs Refer to the WinGMM Program Reference INRAWW BEGIN THE INPUT OF RECTANGULAR PLAT DATA NO RAW EXISTS R
83. erstood rules of construction In some cases WinGMM customized coordinate geometry COGO instructions must be specified to achieve desired results This is commonly referred to as manual subdivision WinGMM stores these instructions for reuse after each adjustment of the network of survey measurements WinGMM Technical Reference Manual doc INTRODUCTION 1 4 GCDB WG TRN V1 00 10262001 ABSTRACTION CHAPTER INTRODUCTION The process to extract the best and most recent information on the surveyed lines that comprise a township is abstraction Information including bearing distance elevation control type of survey line and SID label is compiled from survey plats field notes topographic maps protraction diagrams Master Title Plats other source documents and data already in the database The SID label is a source identifier that GCDB assigns to each survey Data is entered edited using INRAWW Control Abstraction is a two fold process The first step is to determine the control available A data table should be maintained with all control values The latitudes longitudes values are referenced either to the 1927 North American Datum NAD27 or the 1983 North American Datum NAD83 NOTE See GCONW below for information on converting between NAD27 NAD83 Plat Data The second abstraction step consists of extracting information from the surveyed lines that make up a township section lines and township boundaries This infor
84. es are being tried be sure to rename your COR file to some convenient filename because rerunning LSGMMW or APROPW will overwrite your project COR file automatically Another option in COMPARW is to compare coordinates from a PGC file Any combination can be used 2 COR files 2 PGC files or one of each UTMW Input files DEF COR Output file UTM UTMW reads the zone number from the DEF file point id s and coordinates from a COR file It produces an UTM file that is equivalent to a PCCS U file This is a batch process requiring no user input TOLXNW Input files L X identical to the L file of PCCS Output file UTILITIES 9 1 GCDB WG TRN V1 00 10262001 TOLXNW reads the LX file and generates an LXN file The LXN file is about 8 of the size of the LX file and will be used in WinGMM GETLXW Input files LXN Output file LX identical to the L file of PCCS GETLXW reads the LXN file and generates an LX file The BETA version of DXFW LSA required the LX format for making graphics of subdivision lines Version 3 00 000 DXFW require the LXN instead NODUP Input files RAW PCCS R file PGC PCCS P file TEMP JOB for project name Output files RA2 The original RAW file backed up RAW The WinGMM format RAW file no duplicates DUP The report file of NODUP s activities The purpose of NODUP is to find identical coordinates in a coordinate file and assign them all one GCDB ID This automates the
85. for a station when compared to its NAD 27 values with the difference often amounting to hundreds of feet NAD 27 state plane coordinates These are based on zone constants that include false northings and eastings so that negative coordinates do not result The published units are U S Survey Feet NAD 83 state plane coordinates These are based on different zone constants than NAD 27 The most notable change is that different values were assigned for false northings and eastings and the coordinates published by NGS are in meters instead of U S Survey Feet Even when converted to feet NAD 83 coordinates look dramatically different than the NAD 27 coordinates for the same point because the false northings and eastings are different NAD 27 North American Datum of 1927 a datum based on the Clarke Ellipsoid of 1866 and fixed position and orientation at Meade s Ranch in Kansas Based upon this information latitudes and longitudes APPENDIX C C 1 GCDB WG TRN V1 00 10262001 were calculated for all National Geodetic Survey control points based primarily on triangulation The calculation involved a least squares adjustment by hand calculations Number of measurements equals of distances number of angles number of azimuths number of control coordinates Observation a fancy word for measurement Residual the difference between a measurement and its computed quantity based on coordinates it is how much the measurement adjusted
86. fornia GCDB staff to read information from the ADJ file produced by LSGMMW and analyze data for each source within the overall data set Analysis of each source along with critical information discussed in LSGMMW above is written to the REP file This allows the user to analyze and refine error estimates for each individual source The REP file is appended to in multiple runs of SNOOPER providing the user a history of the processing and refinement of error estimates for a township SNOOPER also provides some blunder detection capabilities For a more complete discussion of SNOOPER refer to the WinGMM Software User Guide SNOOPER AND REGSNOOP NOTE While WinGMM programs allow for SID values up to 16 characters SNOOPER only allows for 10 characters in the SID value If you choose to use SNOOPER this must be accounted for and dealt with appropriately INRAWW The error estimate refinement process consists of a cycle of INRAWW GEN LSGMMW analysis of results blunder detection and error estimate refinement if necessary This cycle of events may need to be REFINING ERROR ESTIMATES 6 4 GCDB WG TRN V1 00 10262001 repeated several times If analysis indicates a need to edit error estimates for a data source the SID MAINTENANCE option within INRAWW is selected followed by selection of the EDIT SIDS option A list of SIDs from the SID file is offered and the user chooses the SID to be edited whereupon INRAWW enters into a prompting cycle for each
87. g computed coordinates in an easily accessed data base while providing for data flexibility to facilitate integration of data between various systems PURPOSE AND SCOPE OF THE WinGMM USER GUIDE This WinGMM Reference manual highlights case studies of actual township computations using WinGMM The manual illustrates the analytical and decision making processes you will be involved in as you work through the computations This WinGMM Technical Reference Manual assumes that the user has read and become familiar with the WinGMM Program Reference It also assumes that the user has a competent understanding of various survey methods and a working knowledge of the Windows interface Think of this WinGMM User Guide as a manual to facilitate data organizing entry analysis and management The manual illustrates aspects of what the job requires and what tools you will need to accomplish that task Refer to the WinGMM Software User Guide to find out exactly how to use the tools Please do not hesitate to contact the Service Center Lands amp Resources 303 236 0188 if you have any questions or problems concerning this document GCDB BACKGROUND AND HISTORY The GCDB project originated as a means to provide a common frame of reference for resource data which relies on geographic coordinates and land parcel information based on the PLSS WinGMM assigns geographic coordinate values to PLSS corners allowing resource data and land parcel data to be graphica
88. gram does not use one of these methods the results will be produced very slowly LSAQ uses a bandwidth optimization routine that has been extensively modified for better performance For most survey networks the bandwidth will probably range from 5 30 of the total number of stations This process enables more efficient solution of least squares problems and especially allows big problems to be solved on a personal computer Degrees of freedom number of measurements minus number of unknowns or the number of measurements beyond what is necessary to uniquely define coordinates for each station Error ellipses It should be apparent that the reliability of a traverse point s position will not usually be the same in all directions The position is generally stronger in the traverse direction and weakest away from the traverse directions The error region is an ellipse defined by a radius semi major axis of maximum error SU radius semi minor axis of minimum error SV and the angle from north positive clockwise of the direction of maximum error T Since an error ellipse is two dimensional the one sigma error ellipse only denotes 35 confidence roughly 68 3 squared The same statistical significance reasoning for coordinate standard errors applies to error ellipses it is an internal evaluation of your data and does not relate to external information such as other surveys or existing coordinates Error estimate A surveyor s error est
89. he control position and let it affect many dependent corners would we be introducing uncertainty where none may exist This is the dilemma you will face in processing data through WinGMM To finish this story we did what is really necessary to be sure and had the corner location verified by GPS In this case we made the correct decision as GPS showed the corner to be actually located almost exactly the shift from the digitized coordinates BLUNDER DETECTION 5 10 GCDB WG TRN V1 00 10262001 REFINING ERROR ESTIMATES CHAPTER INTRODUCTION Finding blunders in data sets as described in Chapter 5 is a very important part of the analysis process but we must also detect where our error estimates may need to be refined You will notice that many of the same tools are used for both detecting blunders and refining error estimates This chapter describes the tools for detecting and refining error estimates Examples requiring error estimate refinement Scenario 1 With initial survey data error estimates a township and running through the LSGMMW process you see 3 digitized control points have residuals of 240 feet or more in the ADJ file You suspect the survey data Scenario 2 After robusting a data set you find several E W section lines have taken most of the error perhaps 500 feet or more Scenario 3 After importing a boundary from an adjacent township the residual values on the boundary become very high Scenario 4 After importi
90. hip This is handy where township boundaries are offset or a portion of the boundary is offset IMPORTING COORDINATE DATA If any townships adjacent to your current township have been adjusted you have the option of transferring the computed coordinates from the adjacent township s PGC file These points become listed as fixed control in the current LSA and SD files This option would be used to put control into a township that has no true control While importing plat data from an adjacent township see above the PGC file for the adjacent township must be in the same directory as its RAW file If the PGC file is present the coordinates and plat data are imported otherwise only the plat data is imported The error estimates for these points have to be set at 001 001 in the project DEF file which prevents the Lat Long values from changing fixed boundary The error estimates for the survey lines must be artificially raised by the user to allow all the adjustment to occur on the bearings and distances Holding the error estimates impossibly low on the control and artificially high on the bearings and distances prevents WinGMM from computing realistic error ellipses AUTO IMPORTING SELECTED COORDINATES DATA MERGE CONTROL The purpose is to help automate importing of merge control which is used to merge townships during FORMLSA And it allows for importing merge control from adjacent townships without importing the entire boundary
91. ic value DMZ HP format with positive being clockwise and negative being a counter clockwise correction CON Below is a shortened example of a CON file after GMMCON has been run TWP 0070N RNG 0260E PM GilaSalt R Arizona AZ DATE 93 12 15 ORIGIN 337976 0000 1093540 0000 5000 000 O 0 2000 0000 5000 0000 700140 335733 0015 1093232 0338 9600 000 23 23 27 700140 335733 1745 1093234 3656 9600 000 23 23 83 700700 340220 2080 1093232 0520 9200 000 15 15 27 APPENDIX B B 2 GCDB WG TRN V1 00 10262001 700700 340220 3764 1093234 3880 9200 000 15 15 83 The control data fields are First column if non space is a comment line data will not be used Point ID 6 digit format Latitude in DDMMSS SSSS format Latitude in DDDMMSS SSSS format Elevation in feet units Estimated Northing error in whole feet units Estimated Easting error in whole feet units North American Datum either 27 or 83 The top of each pair is the native unit Above example source data is NAD27 NAD83 is calculated from NAD27 WinGMM does not use everything to the right of column 58 at this time Optional Merge control data MTO8NR26E 200100 200700 M is a special comment line code for merging control TO8NR26E is the adjacent township that is the source of coordinate data 200100 is the point ID in the adjacent township 200700 is the point ID to be used in the current township TO7NR26E RAW TO9NR13E 14 AZ 11111 0 000 0 000 5000 000 1 1 999999 1
92. ield is the point being generated Value is O if not applicable The 3rd field is the known point starting the procedure Intersections have two such points The 4th field is either the endpoint ID defining the bearing from the base point or the quadrant of a user entered bearing Not applicable 0 The 5th field is the bearing value of a user entered bearing Not applicable value is 0 The 6th field is a digit describing whether the computation is based on geodetic line 1 or plane line 2 The 7th field is the record distance to the new corner The 8th field if nonzero is the record distance to the endpoint in which case the record distances will be used as a proportion to apply to the adjusted overall distance In add a line 2 field is point from 3 field is point to all other fields are not applicable so 0 NOT 2 991534 990003 4 100565 813020 100568 813020 240132 260126 260126 300123 The first line describes how many NOT points will follow The next segment is the listing of NOT points NOT points are non boundary points whose lines must be removed for post subdivision display The points will be removed from the COR file This feature will become obsolete so all lines touching this kind of point should be entered into the lines segment The number after the points describes how many lines will follow The last segment is the listing of lines to be removed for post subdivisio
93. imates of measurements assigns appropriate weighting of measurements in a least square adjustment An angle with an error estimate of 2 seconds will be treated as more weighted stronger less chance of adjustment than an angle with an error estimate of 10 seconds This does not mean the angle with the smaller error estimate will always get a smaller adjustment since geometric constraints such as sum of angles in a closed figure also play a major role in dictating amount of adjustment A distance error estimate is usually modeled by a constant plus a ppm addition to account for larger errors generally occurring in longer lines An angle or azimuth error estimate is a function of the instrument s least count the number of repetitions the instrument operator s abilities and the prevailing environmental conditions Experience with instrumentation and the least squares adjustment will allow the surveyor to develop confidence in error estimation Error estimating allows the simultaneous analysis of different measurement types distances angles azimuths control coordinates NAD 83 North American Datum of 1983 a datum based on the GRS 80 Ellipsoid and fixed position and orientation at the center of the earth The measurements used in NAD 27 and additional measurements made by the National Geodetic Survey subsequent to 1927 were subjected to a least squares adjustment this time using a computer This results in a different latitude and longitude
94. imits Large differences in error estimates can also cause difficulties in the order that townships are merged REGIONAL ADJUSTMENT 8 1 GCDB WG TRN V1 00 10262001 No Buffer Originally the concept of regional adjustments was one of adjusting and merging the coordinates of a set of townships within a given geographic location to get the best possible coordinate values from the least squares adjustment This is still the goal but often the results tend to be that the townships with the least control and or least accurate control tend to adjust the most within the region This is especially true for the peripheral townships of any given region Buffer townships around the periphery are used to lessen this effect and provide better coordinate values within the target region Sometimes this is not possible as along a state boundary or a boundary of unsurveyed lands Regions with no adjoining fixed boundaries and no buffers are still produced as necessary and are still the best possible coordinate value results from the least squares adjustment of the region With Buffer Buffer townships should merge correctly with the other buffer and fixed townships with no problems and their boundaries with the new region s townships should be checked for RAW data and error estimate problems In other words the buffer townships are treated exactly the same as any of the townships within the target region The buffer townships serve to provide redundancy for
95. inates of the station specified on the comment line in the CON file When quitting INRAWW it is saved as a control point to LSA and SD files at the specified station Unless 4 CONTROL STATION MAINTENANCE 6 UPDATE CON FILE is selected before quitting the CON file is not updated Every time control is imported using INRAWW it will read the comment line and import the control as specified During each subsequent adjustment coordinates will always be imported Therefore the values of the coordinates may change when the adjacent township has changed This gives FORMLSA a better chance to merge data between the two townships with the least effect on the reliabilities ADDING PLAT DATA FROM SPECIAL SURVEYS AND COMPLEX RECTANGULAR SURVEYS Refer to WinGMM Software User Guide INNAWW When the GCDB scheme deviates far from the standard township it is possible to enter data in a more freeform style In INRAWW s 1 RECORD DATA MAINTENANCE 2 ADD RECORD INFORMATION the next ID and other defaults are automatically generated using a different set of rules than in 2 RETURN TO INPUT OF CARDINAL LINES How these defaults act depend on RAW DATA ENTRY 3 3 GCDB WG TRN V1 00 10262001 whether you are entering rectangular survey data GCDB IDS between 100100 and 710710 or special survey data below 100100 or above 710710 IMPORTING KNOWN CONTROL COORDINATES FROM THE CON FILE This feature controls what points are to be included in the leas
96. is there an error in only one of those measurements Robusting distances and bearings can be extremely useful in resolving this dilemma While lack of sufficient knowledge carries similar risks as elimination of control in the previous paragraph you have not eliminated the survey data so uncertainty you have associated to the survey data is reflected in the error estimates on coordinates generated by LSGMMW The above discussion is not meant to confuse the reader but merely to outline the options and potential pitfalls for handling these types of problems when they are encountered These situations while not necessarily common are also not rare The most difficult decisions that must be made are when there is a high degree of confidence in both survey and control data Take for example the following real life data set An original survey of a township was executed in 1945 by an individual with a reputation of excellent survey work The 1945 brass caps were found by USGS and placed on a 7 5 minute quad dated in the late 1970 s Our analysis of the survey data alone supports our knowledge of the excellent reputation of the surveyor but when combined with the digitized control several of the digitized control points are moving in excess of our estimated accuracy with the largest movement of 110 ft at the NE corner of the township We re mount the quad sheet and verify the coordinates of the control point While we know even the best surveyors make occasi
97. le to ORIGINAL SID and then copy the SNO file created by SNOOPER to the project SID file 5 Run INRAWW using a single point of control GEN LSMINW LSGMMW and SNOOPER 6 Check any measurements listed in JNK against the original source data and correct any data entry errors found If errors are found return to step 5 7 Review the GEN file for section closures and obvious LINK traverse problems 8 Review the ADJ file and look for asterisks Check RMS and maximum values for distances and bearings With a single point of control and error estimates based on step 4 these values should be between 0 5 and 1 0 and the CHI Squared test will probably pass 9 Ifthere are asterisks or RMS values and CHI Squared do not fall within the limits above use PROJECW to turn robusting on Run LSGMMW and robust twice on distances and twice on bearings to localize problems 10 If there is an indication of problems in areas involving complex non rectangular data use CKW to perform specific traverses in those areas Review the CHK file to identify misclosures and check that data against the original source correcting any errors found If errors are found return to step 5 STRATEGY TRACKING DOWN BLUNDERS IN CONTROL DATA When you are satisfied data entry blunders have been eliminated you are ready to introduce an independent check of the plat information in the form of all available control As with the steps above to eliminate errors in the plat
98. lly a tie between rectangular and a special survey would divide any parcel it crosses into two polygons forcing more work to the user who must then combine them To prevent this extra work AUTOI will not include lines that have been identified in the RAW file with a suffix of TIE IDENTIFY LINES THAT ARE LONG CHORDS The long chord of curves are entered into the RAW file just as any surveyed line except that the SID value must contain a suffix of LC APPENDIX A 9 GCDB WG TRN V1 00 10262001 APPENDIX B FILE FORMATS of WinGMM FILES TEMP JOB The first 1 8 characters of the file are the project name usually just township range There is no other data in this file DEF A sample DEF file is on the left descriptive comments on the right comments in parenthesis are not user definable in PROJEC Y not applicable to WinGMM 5 ARIZONA WEST MERCATOR state plane zone 1 NAD27 1 NAD83 2 Survey ft 2 meters 1 Int ft 3 5000 000 default elevation read elevations from LEV file read error estimates from SD 100 1000 0 default for distance error estimate 4 0 default for angle error estimate 120 0 default for bearing error estimate 40 000 default for control N error estimate 40 000 default for control E error estimate Y mean geodetic brgs Y grid brgs N 000 Distance residual printout limit 0 Angle residual printout limit 0 Azimuth residual printout limit error ellipses computed readjust w robusted error estim
99. lly portrayed The locations of resources e g wildlife habitat archeological sites etc can be determined with sufficient accuracy by using a variety of techniques Many resources can be photographed and mapped reasonably accurately these mapped areas can then be digitized from United States Geological Survey USGS maps to obtain geographic coordinates Unfortunately digitizing does not work well with survey data This grid cannot be photographed and mapped as easily as the more visible resource boundaries It is possible and in many areas necessary to map the PLSS to higher accuracy than can be portrayed on standard maps This can be accomplished by combining the best geometric information available and through analysis resolve the inconsistencies inherent in the data from various sources and WinGMM Technical Reference Manual doc INTRODUCTION 1 1 GCDB WG TRN V1 00 10262001 time periods The nature of the collected data allows for ease of maintaining and updating the information contained within GCDB Other GCDB data specifically needed to link legacy BLM lands data with resource data can be collected efficiently through WinGMM GCDB COMPUTATIONS USING WinGMM S LEAST SQUARE ANALYSIS The Bureau of Land Management BLM recognizes that for a Land Record Information System to work and remain useful into the future GCDB must be updateable The GCDB data model reflects this understanding by maintaining all features of the data The type of
100. mation includes bearing quadrant distance and SID label source This information is annotated on township diagrams enlargements of survey plats or detailed drawing listed on abstraction forms entered directly into the RAW file or any combination of these methods depending on the complexity Point identifiers called GCDB IDs are assigned to each corner Values of these point identifiers are rule based when possible to help make subdivision and parcel identification more automatic The remainder of the naming rules provide for a consistent system to help people more quickly recognize corner types and help visualize the basic spatial relationships among the corners Appendix A describes the conventions of numbering GCDB IDS ABSTRACTING STANDARD RECTANGULAR TOWNSHIP The steps necessary to abstract information for a standard rectangular township are as follows 1 Obtain copies of all pertinent plats for the township so that the best and latest record is used Include copies of the plats for the townships to the north south east and west plus the corner townships if an overlap exists 2 If necessary check the field notes to see how lotting and subdivision were done where irregular lotting exists 3 Ithelps to create a sketch of the area encompassed by your data set like a township Color code the different surveys Make a legend cross referencing each color with the SID number 4 If necessary make use of detailed drawings a
101. n display These must be entered in the same order as they exist in the RAW file Points 950xxx generated through automatic intersections in APROP can be entered in this file however subsequent changes in the base files may result in a different numbering scheme for 950xxx points lines in RAW file W TIE must be in the NOT file APROP has a limit of 500 lines for the NOT file APPENDIX B GCDB WG TRN V1 00 10262001 LX The LX file is a PCCS compatible file that is used to support the BLM s LR2000 environment It is produced by WinGMM but not used by it The format is described on the GCDB website http www blm gov gcdb The AN file is a PCCS compatible file that is used to support the BLM s LR2000 environment It is produced by WinGMM but not used by it The format is described on the GCDB website http www blm gov gcdb DXF The DXF file is an AutoCAD compatible file that is used to export GCDB data into AutoCAD and other graphic environments It is produced by WinGMM but not used by it The format is described in documentation about AutoCAD APPENDIX B GCDB WG TRN V1 00 10262001 APPENDIX C WinGMM Glossary Bandwidth Optimization There are many ways to speed up the solution of a system of equations and reduce the number of terms in the equations Some methods other than bandwidth optimization include column profile minimization Helmert blocking and recursive partitioning If a computer pro
102. nd or abstract sheets for complicated areas of survey such as meanders small holding claims surveyed lines with two or more sets of corners etc ABSTRACTION 2 1 5 6 GCDB WG TRN V1 00 10262001 Assign GCDB IDS to each corner Refer to Appendix A GCDB Naming Conventions including figure A 1 for an example of ID coding for a standard township and figure A 2 for an example of labeling a standard section If applicable transfer abstracted information to appropriate abstract sheets See Appendix B for descriptions of example abstraction sheets ABSTRACTING SPECIAL SURVEYS The following steps are performed in abstracting special surveys 1 Obtain copies of all pertinent special survey plats Enlarge or draw detailed areas for clarity 2 Check for resurveys 3 Assign Point Identifiers Refer to Appendix A GCDB Naming Conventions 4 Annotate each special survey boundary line with the corresponding distance and bearing on the plat copy enlargement drawing or abstraction sheet being used 5 Incases of overlapping surveys from various sources digitize the plats to form one picture that shows the interrelation of all the surveys Hard copies of the overall picture and of enlarged details will provide a useful worksheet that will greatly organize your efforts ABSTRACTING MEANDERS Check the meander line field notes for Original meanders Adjusted record meanders New meanders Duplicates handwrit
103. ng a boundary from an adjacent township residual values get excessively high on the lines running into that boundary When you have large error values showing up in either residuals or standard error of unit weight this can be due to 3 basic classes of problems 1 Error estimates not truly reflective of quality This is the situation where the WinGMM user has made estimates that are not consistent with the actual data quality A good example would be placing bearing error estimates of 10 seconds and 1 link on 1858 plat data when the survey was actually performed to 20 links per mile and 4 minutes Another example might be holding digitized control fixed if such control is closely spaced etc Users should recognize that the original surveys of the public lands are known to contain many errors due to many conditions among them hazardous terrain low cost and low land values In difficult terrain it is not uncommon to find that the original surveyor did not run all the lines reported and since closures were not thus obtained they may not have detected other blunders usually in chaining that affected the work In some areas local magnetic attraction or steep side slopes bias bearings 2 Correctable blunders WinGMM is extremely good at identifying problems with data while it takes some experience to ferret out some of the less obvious errors or blunders in the data there are a number of methods and tools provided in WinGMM to assist in this p
104. ng the example above the error estimate for a bad distance would change the most followed by the error estimate for the nearby angles This tends to localize the adjustments into the area where the blunder occurred Repeated robusting localizes the adjustment even more Robusting distances twice and angles twice normally localizes blunders sufficiently to make them easily recognizable in the output ADJ file Robusting distances first is not a random decision but based on the fact it is generally easier to measure distances than bearings and if an error in an individual distance is made it tends to be relatively severe and thus more easy to isolate with a least squares adjustment Once blunders have been identified and addressed by editing errors in the RAW file or using an individual SID the user can import all control points and use robusting to analyze control problems if they exist Robusting is particularly useful in identifying control points with incorrect Point Identifiers If a control point was erroneously given an identifier that indicated it was located 2 miles away from where it actually was this control point would be moved the most in a least squares adjustment However as with distances and bearings other data would also be affected including bearings and distances This can result in an ADJ file that is confusing and very difficult to interpret correctly By robusting a few times on control the erroneous control point may be lo
105. nt and that a published coordinate value is simply a snapshot in time A coordinate measurement is meaningless outside the context of its reliability Lat Long coordinates must also be tied to statistical results The coordinate by itself is not static coordinate values change as better data becomes available Every survey can and frequently does acquire dissimilar coordinates for the same described location There are many cases where surveyors have determined differing coordinates for a given monument We can expect this by the very nature of survey work The question then becomes which coordinate has more reliability Some additional apprehensions then emerge Does this information refer to the same monument Was the correct monument incorrectly measured Is there a typographic error Is there exaggeration in the quality of work Pondering even the simplest of situations results in no conclusive answer yet seamless parcel data is based on a complex network of individual elements that must be interpreted in context PLAT DATA information about the lines between adjacent monument points Overall there is very little usable Lat Long data on survey plats as coordinates are not intended to define legal rights What plats do contain are the bearing and distance measurements between adjacent monuments These line segments can be combined into a continuous interconnected network Since there are imperfections in measurements from normal inherent errors as
106. o intersections identified at the end of the subroutine when the creation of the subdivision template is complete The intersections generated by AUTO INTERSECTION must be inspected to assure their desirability as undesired intersections are indicators of problems with the template Points and lines used in the adjustment or subdivision are not always parcel lines Examples of unwanted points and lines are 1 ties to special surveys 2 ties to control and ties between non sequential corners Including these lines in the LXN file causes two annoyances 1 The unwanted points and lines are distracting when viewing the file in a graphic environment AutoCAD AutoSketch these lines are not on the survey plats 2 AUTO INTERSECTION treats these unwanted lines as parcel boundaries creating intersection points and breaking parcels into too many polygons where it is inappropriate to do so A user during the QLINK process would just have to recombine the polygons into the proper parcels Refer to 5 INPUT DELETE NOT FUNCTIONS in WinGMM Program Reference APROPW for an explanation of how to populate the NOT file with a list of unwanted points and lines USING AUTOIRR AUTO AUTOIRR AND AUTO ELONGATION APROPW can derive a great deal of intelligence out of the RAW file by studying the point IDS and the connectivity of the lines It is possible to avoid a great deal of data entry by letting APROPW outguess what your interaction would be to nons
107. o Figure A 6 Appendix A INTERPRETING THE SUB FILE GCDB WG TRN V1 00 10262001 WHERE IN APROPW TO REMEDY THE SITUATION 1 EDIT INPUT NON STANDARD SECTION 2 STATION NAME SUBSTITUTIONS You tell APROPW the IDS to use 1 EDIT ZINPUT NON STANDARD SECTION 9 DEFINE PROPORTIONED STATIONS You list the IDS of corners to move 1 EDIT INPUT NON STANDARD SECTION 3 DEFINE DOUBLE SECTION CORNERS List IDS which direction they control 1 EDIT INPUT NON STANDARD SECTION 4 QUARTER CORNER EDIT List the ID of the non computable corner 1 EDIT INPUT NON STANDARD SECTION 5 CENTER OF SECTION EDIT or 6 EXTERIOR SIXTEENTH EDIT or 7 INTERIOR SIXTEENTH EDIT or 8 CENTER OF QUARTER SECTION EDIT List the corners that should not be computed non computables 1 EDIT INPUT NON STANDARD SECTION 7 INTERIOR SIXTEENTH EDIT You must determine the parenthetical distances of the section centerline and specify them here There are two choices manually as follows 2 ADD EXTRA COMPUTATIONS 3 INPUT ADDITIONS 1 TRAVERSE PROPORTION 2 GENERAL INTERSECTIONS You must input computations to compute the necessary proportions and intersections automatically as follows 2 ADD EXTRA COMPUTATIONS 3 INPUT ADDITIONS 5 AUTOMATIC ELONGATED SECTION COMPUTATIONS You follow the necessary prompts This file contains valuable information for QA QC The SUB file is a report file that can be viewed or REFINI
108. of error inherent in the data Users want to resolve all the geometric discrepancies in this data but protect the integrity of the better data Least squares analysis combines all this data ascertains the ambiguity and figures out how deviations with each coordinate and bearing and distance affect the entire project It then reconciles the network conducting multiple iterations adjusting the suspect data more than it adjusts the trusted data to the degree specified by the user s assumptions until the complete project is resolved to its best fit Each time this analysis program is run it provides a Lat Long for every point in the adjusted area and an item by item report of how much each measurement was adjusted This is where the user begins interacting with the process to refine the final answer The report includes a numeric value residual for each bearing distance and control coordinate that compares the user s expectations with the amount of adjustment each point or bearing received to achieve the best solution A second number called a snoop number determined by the amount of error estimated and the amount actually incorporated in the adjustment is also reported snoop number of 7 0 translates to You thought this spot had good data but in order to make everything fit together I had to bend the measurement seven times as much as you asked me to In this way all the problem areas are brought into focus This is how data entry mistakes
109. omprised of different sources such as an original 1891 survey and a resurvey performed in 1981 on a portion of the section boundaries where significant distortion in the original survey was identified When data for sections are from the same source and there are misclosures reported for adjoining sections that are similar but opposite in direction there is a higher probability of blunder on the line common to those sections Most of the time these blunders will be in data entry and are corrected by editing the RAW file to reflect the correct information Sometimes they are measurement or platting errors that can be dealt with by assigning a separate error estimate to the individual line s of data in the RAW file Users must be aware of how many sections can be closed based on their input RAW data and ensure a closure was calculated for all possible sections At the end of the section in GEN that performs these loop closures around sections there is a summation of the loop closures including an overall average precision of closures for all sections evaluated Following the section of the GEN file on LOOP closures is information regarding LINK traverses LINK traverses are traverses of the RAW information to generate approximate coordinates of all unknowns non control points for LSGMMW These traverses will also include non rectangular data traverses if they exist in the RAW file and will sometimes be closed traverses of this type of data As
110. on the W and S elongations and 664 666 668 672 on the N and E elongations Other possibilities are 105 109 111 and 662 676 678 See figure A 6 for examples Note that these 1 16ths can be left out if AUTO ELONGATION is used Shortened Sections and Missing Sections see figure A 7 Assign point identifiers to short sections using the standard section point IDs See figure 7 for an example The standard point identifiers are also used for townships missing sections See figure A 7 If a township is only 5 miles high then use the point identifiers usual for that section SPECIAL SURVEYS includes Tracts Milepost Surveys and Mineral Surveys You are advised to use the rectangular ID number where a special survey intersects or bounds the section lines as described earlierod See figure A 8 For the remaining survey corners assign a six digit GCDB segment identifier that is used for special survey corners there is no relation as to the corner s position within the rectangular scheme Instead the segment identifier describes a particular survey type The segment identifier is made up of two parts The first three digits of the segment identifier prefix are assigned according to survey type and each survey has at least one unique prefix that is used for each corner of the survey The second three digits suffix are numbered sequentially from 000 999 and may be incremented by 2 5 or 10 to leave room for subsequent addi
111. onal mistakes there is no reason to suspect this level of error by the surveyor On the other hand we also know that USGS location of found corner symbols is generally of a much higher accuracy than indicated in this data set Following the process above after introducing the control data we robust twice on control in LSGMMW and predictably the error is localized to the control point at the NE corner of the township and the other control points that were moving excessively are now consistent with the observed average quality of control in the ADJ file In this particular case as the corner in question is common to 3 other townships originally surveyed in the same era we defer final decision until those townships are completed WinGMM processing of those data sets supports the uncertainty of the control at the township corner but may not be considered to be conclusive as there is no indication the adjoining original surveys visited the corner in question However based on the preponderance of evidence the decision is made the control point is bad and it is eliminated in the processing of all four townships resulting in small error estimates on the corner in question So we made a decision but is it the right one Is that corner really in a significantly different position as we are showing in GCDB Have we done the user of GCDB any favors by eliminating the control and thus hiding the uncertainty that exists On the other hand if we had kept t
112. oninnnononocinnnanananonocccononnnnanonocccononananens 2 3 GCONW and GCONHPW NAD Datum Conversions 2 4 DATA ENTRYEANDEDITIN poner nre n ETE ad annie 3 1 INRACWAWS s NIE 3 1 CHAPTER INTRODUCGTION eite ete Aa tee I 3 1 BEGIN THE INPUT OF RECTANGULAR PLAT DATA NO RAW EXISTS 1 ccce 3 1 IMPORTING DATA FROM ADJACENT TOWNSHIPS 1 eere 3 2 IMPORTING PLAT DATA dette A e vH ete eet oe re E eee ce eee de eo Pee te Y eee Beka EP 3 2 IMPORTING COORDINATE DATA ia tai 3 2 AUTO IMPORTING SELECTED COORDINATES DATA MERGE CONTROL ccr 3 2 IMPORTING KNOWN CONTROL COORDINATES FROM THE CON FILE eene 3 4 LISTING DATA ON THE SCREEN TO REVIEW AND VERIFY YOUR WORK cttm 3 4 INRAWW EDITINCG A a iue 3 4 GCDB WG TRN V1 00 10262001 EDITING OR DELETING RECORD DATA Anaiari iea EE aA EET ESEESE EE cnn eene trennen 3 4 ADDING TO CHANGING OR DELETING CONTROL 3 5 ADDING TO OR CHANGING SID DATA onccion iieii eidion ii enie ein 3 5 QUITTING THE PROGRAM CREATION OF THE NEWEST RAW SD AND LSA FILES 3 5 ADJUSTMENT AND ANALYSIS OF GEOMETRIC DATA nennen eren ener 4 1 CHAPTER INTRODUCTION 2 triti nat e e ete DECIR DOR DRE ROT UP ER 4 1 THE ADJUSTMENT ANALYSIS PROCESS deett eet ree re
113. ps See Data Entry and Editing AUTO IMPORTING SELECTED COORDINATES DATA FROM THE BOUNDARIES OF ADJACENT TOWNSHIPS MERGE CONTROL for an explanation and WinGMM Program Reference USING INRAWW TO ADD MERGE CONTROL FOR FORMLSA MERGES for instructions on it s use Merge control is a tool of last resort and should only be used in those rare instances where error estimates could not be adjusted enough to take in account the poor quality of survey data It should never be used in areas of good quality survey data If itis not merging in those areas there is some other problem Crossing State Plane Zone edges One problem that may be encountered is the use of files from townships that were processed in a State Plane Zone that is different than the region being worked on Use the program CHZONEW to change the files of these townships to the appropriate zone Refer to this document Chapter 9 CHZONEW and the WinGMM Software User Guide document FORMREL The formrelw exe program allows the User the ability to calculate the reliabilities of individual townships in a region where rigid control along regional boundaries was used and to then replace a reliability of zero with the actual reliability calculated in the regional adjustment The results of the adjusted values are then entered into the coordinate files for the individual townships after a regional adjustment is completed REGIONAL ADJUSTMENT 8 5 GCDB WG TRN V1 00 10262001 WinGMM UTILIT
114. put valid error estimates for the bearings in the data set RAWW Technique Prepares unadjusted RAW data for graphical viewing on your screen It also writes data inconsistencies into the CLS file Despite the best efforts human nature is such that sometimes relatively minor errors are made in data entry that will result in an adjustment that cannot be analyzed using normal WinGMM processes When problems like lines missing from your RAW file mis numbered point IDS wrong quadrants transposed numbers and other hard to find mistakes in your textual files exist you may use RAWW to get a graphical representation of what your RAW and CON files look like The WinGMM program RAWW produces the RAW LSA file that can be used to actually get the picture and a CLS closure file which is an ASCII report of common data entry errors DXFW Technique Store data in a graphic file so it can be displayed or plotted DXFW will give you more flexibility because you can import the picture into any software capable of reading a DXF file There are many ways to view print plot or even edit the picture from these graphic programs A printout of a DXF file can even be made through Word Perfect DXFW has several options to select from in creating a DXF file When looking for a blunder during abstraction of the raw data it is best to use coordinates and lines from the LSA file For a view of the final WinGMM product it is best to use coordinates from th
115. r Manual BLUNDER DETECTION TOOLS AND STRATEGY and the WinGMM Program Reference LSMINW and LSGMMW THE ADJUSTMENT ANALYSIS PROCESS There are three major programs processes used to adjust and analyze the merging of the survey and control data more comprehensive explanation of these programs can be found in the WinGMM Program Reference GEN generates approximate coordinates by running traverses between control points and performing compass rule adjustments where possible It produces two files 1 The GEN file which is an ASCII file showing you misclosures of survey data by section and 2 A new LSA which appends approximate coordinates to the bottom of the LSA file produced by INRAWW LSMINW performs a least square adjustment of the survey data using only one control point Because a single control point is used it must be assumed to be without error LSMINW reads the SD file created by INRAWW to determine how much relative adjustment to apply to each survey measurement entered in the RAW file LSMINW produces a MIN file that is similar to an ADJ file see LSGMMW below It lists how much each measurement was adjusted and compares it to how much you estimated it would adjust This file is very useful in tracking down any data entry blunders and to help gauge the quality of the survey data LSGMMW refers to a process where a least square adjustment and analysis of the survey data and all control points that have been imported f
116. r pertain to the North and South direction only and should progress from the South boundary of the township in increasing values to the North boundary of the township NONSTANDARD TOWNSHIPS includes offset interior lines Triple Section Corners elongated sections shortened sections To develop the point identifier for triple section corners and any other odd situations keep in mind the dual purpose of the ID system 1 To define the corner s function WinGMM anticipates that you will follow the rules for naming GCDB IDs This speeds up data entry INRAWW and automatic subdivision APROPW 2 To define the corner s general position along a line This helps us quickly differentiate among several angle points the software is not reliant on the numbering system If you must use a non standard ID for a corner that plays a part in subdivision then you must later tell the software what the corner s function is Refer to the Subdivision chapter The only thing you have lost is that APPENDIX A 6 GCDB WG TRN V1 00 10262001 the software couldnt AUTOMATICALLY figure out what it needs to know Offset Interior Lines see figure A 4 A great deal of time confusion and some disk space can be minimized with a new variation on the point ID scheme for offset interior corners There is no longer any need to placel o values on both the prefix and suffix nor is they re a need to make both IDs non nominal You may now choose one side to be th
117. re so WinGMM is built to recognize suffixes to the SID Suffixes are used to isolate areas of a survey that need a different error estimate identify lines that are ties not boundary lines identify lines that are long chords SID values 4588 4588a 4588 TIE 4588 LCS all point to the same survey 4588 The suffixes are used for various purposes as described below ISOLATE AREAS OF A SURVEY THAT NEED A DIFFERENT ERROR ESTIMATE Initially error estimates are based on values that are tied to a SID in the SID file surveys however are not of the same quality Upon discovering that certain areas need higher or lower error estimate you are expected to assign the error estimates accordingly Prior to SID suffixes the SD file was edited via SD EXE or a text editor Because these estimates were not tied to a SID they were hard to recreate if the SD file was deleted Also the lines that were custom edited were very difficult to identify from those tied to SIDs The suffixes were implemented to allow all error estimates to be tied to a SID in the SID file Alphabetic characters are appended to the base SID to create a new SID The new SID and its values are placed in the SID file and the RAW file is edited accordingly IDENTIFY LINES THAT ARE TIES NOT BOUNDARY LINES In preparing the data for merging with LLD APROP will identify all the polygons These minimal polygons will later be combined to form parcels as listed in LLD Norma
118. rocess Examples of this class of problem are incorrect or bad control coordinates incorrect entry of plat data and incorrect or inconsistent point naming In all of these cases the blunder can and should be found and corrected 3 Unresolvable blunders REFINING ERROR ESTIMATES 6 1 GCDB WG TRN V1 00 10262001 Sometimes errors or blunders in data exist where it is very difficult or even impossible to determine the exact location or nature of These can fall into several classes Control You digitized several found corner symbols off of a 7 5 minute quad and analysis indicates that one of these points does not agree with the survey You do not know if the USGS identified the wrong point misplaced a correct point on the quad or the actual corner on the ground is where they say and it is the survey that has a blunder in it If you cannot go to the field to verify the location you may not be able to do much to find out what USGS did Lacking any concrete knowledge of the survey data you must make a judgment call based on preponderance of WinGMM information Keep in mind that when the contract method of surveys was abandoned in favor of a civil service approach very rigorous quality control measures were put in place and in the vast majority of cases adhered to On the other hand USGS places a 90 confidence on the placement of found corner symbols on 7 5 minute quads and our analysis of hundreds of thousands of digitized found corner symbols
119. rom the CON file is performed As with LSMINW LSGMMW reads the SD file to determine how much relative adjustment to apply to survey measurements In addition it also reads the CON file to determine how much relative adjustment to apply to control points There are several versions of the least squares programs that differ depending on the Operating System used and how much computer memory RAM is available A description of these various versions is contained in the WinGMM Program Manual LSGMMW LSGMMW produces an ADJ file that among other information about the adjustment lists how much each measurement was adjusted residual and compares that value against the input estimate of how much it should adjust snoop number When a measurement adjusts excessively more than 3 times the estimate data is marked with asterisks to indicate a higher probability of a blunder This file is extremely useful in identifying potential blunders in and help gauge the quality of survey and control data ADJUSTMENT 4 1 GCDB WG TRN V1 00 10262001 BLUNDER DETECTION TOOLS AND STRATEGY CHAPTER INTRODUCTION WinGMM utilizes a least squares adjustment to merge survey and control data Due to a combination of the laws of physics and human nature there are errors in every measurement used in the WinGMM process For the purposes of WinGMM processing a blunder is defined as an error in an individual measurement survey data or control that is large enough in m
120. scrolls through your monitor An added benefit in using INRAWW to list your RAW file data is that bearings are displayed more like a plat see immediately below in feet FROM DIST FT ERR FT BEARING ERR SID 495 100140 940020 86 592 1 043 S 49 16 0 E 0 0 20 33752 496 940020 939020 1499 982 1 750 S 79 40 0 E 0 0 20 33752 BLUNDER DETECTION 5 3 GCDB WG TRN V1 00 10262001 497 940010 939010 1499 982 1 750 S 79 40 0 E 0 0 20 33752 498 939020 938010 1496 022 1 748 S 79 40 0 E 0 0 20 33752 Then back to chains REC FROM DIST CH ERR FT BEARING ERR SID 495 100140 940020 1 312 1 043 S 49 16 O E 0 0 20 33752 496 940020 939020 22 727 1 750 S 79 40 O E 0 0 20 33752 497 940010 939010 22 727 1 750 S 79 40 O E 0 0 20 33752 498 939020 938010 22 667 1 748 S 79 40 O E 0 0 20 33752 CKW Technique User defined traverses The program CKW is similar to the program GEN in that it automatically performs RAW data traverses around any sections possible writing this information to the CHK file The format of this section closure data in the CHK file is different from GEN as follows 2 2 2 E K K K K K K K K K KK K K K K Ok TRAVERSE CLOSURE REPORT FOR SECTION 31 SUM OF DISTANCES ALONG TRAVERSEIS 4 00 MILES CLOSURE IN NORTHING Y 5 9 FT CLOSURE IN EASTING X 8 FT LINEAR ERROR OF CLOSURE IS 6 0 FT STANDARD PRECISION IS 1 3549 STATIONS IN TRAVERSE 100100 100140 100200 120200 140200 200200 2
121. sks DO YOU WANT TO READJUST WITH NEW WEIGHTS Y N When you answer YES LSGMMW will ask you which measurements you want to robust So whatisrobusting Here is an example Say a bad E W distance was entered This could be a data entry error or correct entry of a bad measurement but otherwise the survey data was good During LSGMMW the least squares adjustment will find the bad geometry but will not know if it is the E W distances or the bearings coming into the end points from the N and S Your error estimates may tell LSGMMW not to adjust any of this data very much because you believe the source data is accurate LSGMMW will spread the error over a wide area to make it fit but the measurements closest to the bad data will be adjusted more If robusting is turned on LSGMMW gives you the option to re weight control distances angles or BLUNDER DETECTION 5 2 GCDB WG TRN V1 00 10262001 bearings after performing a least squares adjustment You may choose to re weight one or all of these measurements and you may robust repeatedly on any individual measurement type s When you quit this prompting cycle LSGMMW will run through the adjustment again reweighing the selected measurements based on actual adjustments observed as opposed to error estimates from the original least squares adjustment As noted in the previous paragraph the measurements closest to a blunder will be adjusted the most in a standard no robusting LSGMMW run So in robusti
122. sociated with surveying and from measurements derived at various points in time the network doesn t fit geometrically with itself Take any two monuments derived from plat data numerous slightly different bearings and distances can be computed between them conditional on what combination of connecting lines is used in the computations If the two monuments are held as control coordinates we can also apply a certain geometry to the latitudes longitudes to determine yet another bearing and distance WinGMM Technical Reference Manual doc INTRODUCTION 1 2 GCDB WG TRN V1 00 10262001 It is this uncertainty that makes bearing and distance information difficult to interpret COMBINING SOURCE DATA control coordinates and plat bearings distances The result of adjusting the control coordinates with plat bearings and distances is that latitudes longitudes of all the intermediate monuments will be computed This is the only clue we have as to the position of monuments that may not have been visited since they were set How good these computed Lat Long coordinates are depends ultimately on the reliability of the source data It is imperative to discern the quality of our source data before we can arrive at an optimal solution of Lat Long values The quality of plat bearings and distances range from precise to nearly worthless and the quality of control coordinates differ just as dramatically The determination of whether weaknesses exist in the control
123. support LR2000 The theory behind all of this is to start with GCDB lines and points of the PLSS convert the lines and points to polygon s determine a centroid for the polygon and define which line and nominal location it is associated with in LLD LINKING PROGRAM ORDER The linking programs must be executed in proper sequence as one program creates files that the next program reads The order in which these programs are run is GETLLD ROPLY LLD An explanation of each of the linking programs can be found below Before the linking programs are run an LLD file containing LLD for the project township must be created from the gt master LLD which is a file that contains LLD for the entire state The township LLD file must be in the directory containing the rest of the GCDB township files for the township to be linked GETLLD Input file township LLD Output file LOT GETLLD prompts for the extent and direction N S E W of elongation for each lot by section number in townships that contain elongated sections GETLLD runs in batch mode if the elongated section scenario does not exist in a township GETLLD reads the LLD file and makes a lot file The LOT file contains section number the numbers 1 16 for the A P nominal locations identifies elongation and how it is elongated the lot number if it exists the acreage survey type and survey number RPLOY Input file COR DEF NOT RAW Output file RPO RPLOY runs in
124. t it can only use NAD83 coordinates and conversion can only be done in one direction during a run GCONW looks in the CON file for NAD27 coordinates without NAD83 coordinates and computes the NAD83 values and writes the data on the next line It also looks for NAD83 coordinates without NAD27 coordinates and computes them The computed values are placed into the CON and coded 27 or 83 in columns 56 amp 57 All comment lines are preserved lines with non space character in column 1 GCONHPW does the same thing for HARN but codes it HP in INRAWW looks for a datum in columns 56 57 of the CON file Anything but 83 or HP in those columns means NAD27 The project datum is defined in the DEF file and control coordinates are imported in that datum If Update con file option is used and NAD27 is defined all NAD83 coordinates are simply written back to the CON and are not made comments Same for NAD27 coordinates if in NAD83 is defined NOTE Delete the LSA and SD files before running INRAWW other WinGMM program s computations will be based on whichever datum was set by PROJECW and is defined in the DEF file A CON file after GCONW has ran will have a 1 1 match of NAD27 and NAD83 coordinates After GCONHPW the CON file will have a 1 1 1 match of NAD27 NAD83 and HARN coordinates GCONW and GCONHPW will ignore any lines that have been commented out with an asterisk This is a con file before GCONW TEST CON ORIGIN 451019
125. t squares adjustment Control points are imported from the CON file into the SD and LSA files LSGMMW does not read the CON file Strategy Although you must eventually choose 1 option 2 is provided to allow you to initially use GEN LSGMMW adjustment analysis to test the data in the RAW file After importing just one control point into SD and LSA you run the data through GEN LSGMMW and CHECKER All three programs give you reports on where the most adjustment occurred These are spots to look for possible data entry errors Once the data errors are corrected the same adjustment reports are used to refine your error estimates Refer to the discussions on interpreting the GEN file ADJ file and the CHK file below Once satisfied that the RAW file is correct you run INRAWW 4 CONTROL STATION MAINTENANCE 5 IMPORT CONTROL FROM A CON FILE 1 READ ALL CONTROL IN CON FILE LISTING DATA ON THE SCREEN TO REVIEW AND VERIFY YOUR WORK Refer to WinGMM Software User Guide INRAWW There will be many times that you will want to see the data that you have input To find out where you left off To check for completeness To check for correctness To find the RECORD of a particular piece of data To see your distances displayed in a different unit of measure To list plat data choose 1 LIST RECORD INFORMATION from INRAWW s main menu You will also be presented with an opportunity to LIST plat data from within INRAWW s
126. tandard sections AUTOIRR listed in APROPW s 1 EDIT ZINPUT NON STANDARD SECTION BREAKDOWN INFORMATION menu as 11 PRELIMINARY IRREGULAR IDENTIFICATION will make an entry in the IRR file for the section that you are currently in AUTO AUTOIRR listed on the main APROPW menu as AUTOMATIC PRELIMINARY NON STANDARD BREAKDOWN OF ALL SECTIONS will make entries for all nonstandard sections including calculating and storing parentheticals for all sections lotted against the exterior It does not take out 1 4 corners and 1 16th corners on foreshortened sections Strategy Once AUTO AUTOIRR has stored the parentheticals you may remove the nonexistent corners without having to calculate and force them into IRR Note there are very unusual situations that AUTOIRR REFINING ERROR ESTIMATES 7 6 GCDB WG TRN V1 00 10262001 functions are not able to treat properly it is your responsibility to inspect the SUB file for correctness and to make appropriate changes through APROPW AUTO ELONGATION listed under 2 ADD COMPUTATIONS as 5 AUTOMATIC ELONGATED SECTION COMPUTATIONS makes entries into your ADD file for all elongated 1 16ths for the prompted section There are certain conditions that must be met in order for AUTO ELONGATION to generate acceptable results 1 All 1 16ths between the 1 4 corner and the township exterior must be left out of the RAW file so the distance is the overall distance from the 1 4 corner to the township exterior Or if th
127. ted Sections S S T z E P 68 o amp o 9 e e o w o 5 a Ww a a a ri S A Tes RU E d WU Section 4 does not exist oS 96 iT 6 6 OtherWise use usual suffix for Xo 0 A A 1 2 rectangular line A Og 5 Vo X 9 9 Y 3 e 9 O Y Q 6 6 S 90 4 80 ES i9 pS Y 0 x we Figure A 7 GCDB IDs For Shortened Or Missing Sections And Milepost Surveys APPENDIX A A 5 GCDB WG TRN V1 00 10262001 Figure A 8 GCDB IDs For Special Surveys 3 or 4 Each XxxY yy has a prefix Xxx and a suffix Yyy X and Y start at 1 and increase by miles east or north xx and yy increase by tens of chains within each mile The one s place Xxx or Y yy is reserved for arectangular corner point 1 2 8 or 9 offset corners in Tp interior 3 or 73 offset corners on Tp boundaries 3 4 6 or 74 intersection with special surveys 5 for 1 256th corners SUMMARY Point Identifier Standards In summary location based numbering is used along lines of the rectangular system The point identifier a six digit number is constructed of two three digit sets The first three digits pertain to the East and West direction only and should progress from the West boundary of the township in increasing values to the East boundary of the township The second three digits of the point identifie
128. ten typed Fixed and limiting boundary Informative traverse Evaluate meanders see example in Figure A 8 Determine which meander lines continue to control property rights 1 Ascertain whether meanders have been superseded by new meanders 2 Where duplicate meanders exist note that the rectangular meander line will normally control 3 Determine whether record meanders have been adjusted 4 Determine which informative traverse must be abstracted a Traverses must be abstracted if they form the boundary of an accreted area which is divided by division of accretion lines based on the informative traverse b Ifthe traverse is only for area determination or for locating a certain feature it is not shown ABSTRACTION 2 2 GCDB WG TRN V1 00 10262001 Identify rivers that have meanders on only one bank Determine the best method for identifying banks without meanders l Digitize the plat 2 Use the width of the river Assign the segment identifier Refer to Appendix A PREPARING THE COMPUTER FOR A NEW TOWNSHIP 1 Name the project according to GCDB Township naming convention Use the GCDB Township naming convention to create a name of your next project See Appendix A pg A 1 If your township is T 34 N R 07 W then your project name will be T34NRO7W Although WinGMM Version 1 00 will work entirely with any project name use of the standard naming conventions in such processes as getting boundary data from adjacent townships
129. tions if needed around the survey APPENDIX A A 7 GCDB WG TRN V1 00 10262001 Note that WinGMM will work with totally random numbers for special surveys as long as they are unique These rules are made to help you and those in the future make sense out of complex data sets Also some post processing software depends on the prefixes to speed automatic cataloging of the data for BLM s LR2000 Tracts see figure A 8 The segment identifiers for tracts have a prefix of 8 plus the tract number These values can range from 837 to 899 The second three digits suffix range from 000 999 as described above for each tract corner Figure A 8 illustrates the numbering convention for Tract 38 Boundary Milepost Surveys Number milepost corners and all the corners along the boundary reservation or grant boundary with a segment identifier whose prefix ranges from 711 799 The second three digits may increment up the line or reflect the milepost number Mineral Surveys see figure A 8 The prefix of the mineral surveys segment identifier can range from 900 999 The second three digits are assigned the same as all special surveys i e incrementing around the survey figure A 8 Meander Lines see figure A 8 The prefix will be a number between 800 836 The entire meander line will have this prefix through the whole township For rivers right bank meanders will be prefixed by even numbers for example 806 while left bank meanders will b
130. township exteriors 3 4 6 or 7 i e 3 of from a rectangular corner A 3 4 6 or 7 may also be used when assigning point identifiers to elongated section subdivision corners and to corners at the intersection of special survey lines with rectangular lines See Figure 6 and Figure 8 5 is used for 1 256th corners Currently provisions for subdivision below 1 256th corners are not part of the GCDB ID rules If such parcels are surveyed the corners should be assigned IDs similar to intersections with special survey APPENDIX A A 2 GCDB WG TRN V1 00 10262001 Figure A 1 Township With GCDB ID Number For Full Section Corners Figure A 2 Section 8 With GCDB ID s to the 1 16 Level APPENDIX A A 3 GCDB WG TRN V1 00 10262001 Figure A 3 GCDB IDs For Offset Corners Along Township Exteriors 3 Figure A 4 GCDB IDs For Offset Corners in Township Interior 2 Figure 5 GCDB IDs For Triple Section Corners APPENDIX A A 4 GCDB WG TRN V1 00 10262001 295 400 go 997 e o9 AO PEN Q oo 29 ANO Volo SE po So do 19 oA e AS D p D d 4999 050 e 609 amp 6 o0 e o o SM E uS S oS am um S Sg S S OG FG QU XQ A Figure 6 GCDB IDs For Elonga
131. with closure around sections these types of information can be extremely useful in identifying blunders in data entry Because the purpose of these traverses is to calculate approximate coordinates once and only once for all unknown stations the user may not see all closures they wish to evaluate contained in the GEN file The program CKW covered later in this chapter allows users to input specific traverses for evaluation The third type of information contained in the GEN file is a listing of all points for which approximate coordinates were developed but for which a compass rule adjustment can not be performed These types of information are listed in the format STATION XXXXXX LOCATED BY DISTANCE BEARING FROM STATION and can be found by performing a search for the word LOCATE While this type of data is most often legitimate this can be useful in identifying blunders like incorrect data entry of point IDS in the RAW file This is especially true in data sets where the data is so good two points that were meant to have the same point ID are created at coordinates so close that it is extremely difficult to catch such errors by graphical methods PROJECW Technique ROBUSTING Refer to WinGMM Program Reference SGMMW PROJECW must be run to specify that you want to robust by setting option 15 READJUST WITH ROBUSTED ERROR ESTIMATES to YES This causes an additional prompt to occur just before the normal exit from LSGMMW that a
132. ystem of Equations in a least squares adjustment you solve an n x n system of equations each iteration where n equals the number of unknown quantities In a 20 station traverse there are 40 unknowns 20 N 20 E coordinates This means a 40 equations 40 unknowns system of equations must be solved Even for a computer this is a slow process APPENDIX C C 3

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