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Compass & Tape - National Speleological Society

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2. Surveying with Auriga Auriga can be used as an electronic notebook to input numeric survey data and instantly view the line plot while in the cave ascientific calculator to convert survey shots into Cartesian coordinates while at camp an input device to transfer survey data from the paper notebook to the PC without wasting battery power The most common use for Auriga is to input survey data while in the cave But what about carrying a Palmin this muddy wet and often cold environment Once you accept that you must treat the Palm with proper care it is no problem In easier caves wrap ping the Palm in a Ziploc bag and carrying it inside the survey notebook still required for sketching may be sufficient Alternatively Aquacase makes for US 30 a watertight write through pouch that can be screwed Figure 3 A combination binder for both numeric data and sketching inside the cover of a regular survey binder see Figure 3 This option offers the convenience of inputting the numeric data on the Palm side and sketching the cave on the paper side in a survey notebook that retains its usual thickness Lastly Armor makes for US 49 a watertight box with a write through screen on the cover the box can be fitted with a homemade flap to cover this screen between survey stations Auriga is designed so that you never have to take the Palm out of the pouch or box while in the cave and it was im proved accordingly to e
3. KAN ity A9 E c6 GE 9S8 r 65 A09 6 SOL 92 6 L9 6 SEE 95 8 OL t6 i 8 288 ARE 1 02 OL PP 90 hb Sb 9g WAA 8 tO fe LL 28 9 205 98 S g GZ 6 9 L o Zy e 9 4 amp 9 0L 58 SY 6 Og 58 vk Lvl 081 912 655 Ce 902 68 Lo RRA vit 8 Bol 95 26 88 LOL WEE LL 8 8 L tE tc tr 1401413 is ea 9v c8 26 84 bt wii OE 9 S 59 EIA i99 0 05 781 602 998 86 507 rM a 94 be 96 i a 08 os ee 89 Pes ibl 5 LS 69 BR 01 62 91 pe Ibe 0687 EE ee i T Se 88 AL 69 05 9c 28 LES CRS LO 9S6 PIA Svr 081 960 582 Lg dr libe 26 9 252 ZZ MAA 587 891 Lyc 85 1 9 85 phe pe 8 ZEL Sv 651 6v 96 ioc 06 9 90 60 65 92 1 85 LZ Lb S ux 627 Ob 6 2 91 02 L6 Zg 021 ZZ eo 5 2 ANAL js e3 6094 6 6081 8 LASI 89 98 951 1 AGS b 0 S8rl LPP L LEevt 8851 cegek OSEL SM AAA erek FAA AA SATA S 9ESb 2ci S88Lkk 81 991 trok 086 6S 6 8 88 6 L8 984 6k4 L04 S 9 99 85
4. 95 96 iia Ane h A 96 198 9 8L A 68 OL m RAN ISL 1047 20 90 GL 88 499 98 CE 94 9 9z v6 91 TR vA 25225 01 9 LO T Z 19 0 19 8 99 9 i 6 Lk 001 AENEA E T 1 6 68 092 21043 8c 8g A 965 6k SL th p Ghr SL 9L C b 4 6 9 4 5 8 i E X E Y E G 9z 9 59 0 6 6 js g 8 9 0 Z T 90 ZA SE 108 PIS Ae 1 RA Oe 5 8 bale 9 ONE 2 7 908 ie S 0 92 iuc 9C S bas SLM 1S Oo 72 LS ss SZ 0 SAMBA 66S GL CI L 5 S4 S Sg gg Sc 0 Scl O iwNoioi iixri G2 g G4 0 Sc D NNUN SC 9 L 5 S L s 16 p O 10 c 4O O00 10 A dad Md Moti L8 8 LZ 06 69 4 8 4 E AL g L 995 05 beck 0 e lt 181 I ae 9 LOL 99 91 0 L ec NENNT 8 ZEL Ig LLL 56901 02 ve Ye Bec LZZ 9905 co BADE 8 8 85 01 92 861 8 0Sc ett ke G QN ay Ate 8 FM IUE 984 9 LOL E OGL 081 891 8 8S4 SZAZ EMMAT 8 8 1 1 881 3
5. lems sighting on the station light Figure 16 Compass azimuths for Lines 20W thru 100W The Gypsum Cave Anomaly The lava flow containing Gypsum Cave the longest lava tube in Idaho comes from a vent over 10 miles away Itis therefore logical to assume that a lava tube would exist upstream from Gypsum s en trance A magnetometer survey does in fact reveal a very large void starting about 50 feet up flow from the sink leading into the cave as shown in Figure 18 This is not just another anomaly itis the largest in magni tude and width and the best void defining anomaly that I have ever seen It must represent a cavity of considerable dimensions A resistivity survey was also conducted over the magnetic anomaly to further define the dimensions Surprisingly instead of delineating a huge resistivity high as would be expected over such a large void the result was a very low resistivity anomaly Apparently the cave floor is covered or the cavity filled with highly conductive wet salts which effectively short circuits the resistivity prospecting current Compass amp Tape Volume 17 No I Issue 57 2 A compass azimuth survey over the anomaly yielded astonishing results Figure 19 Not only was the main magnetic anomaly large beyond any expectations but the compass bearing deviations were large enough to easily delineate the tube beneath the surface for the entire 200 foot length of the magne tometer survey T
6. 12 Palmillx 3 12 1 2 Big room back to entrance 5505 11 055 2925 Figure 1 Palm top running Auriga the cave map screen Loop errors are graphically displayed with a dotted line between the actual and theoretical ends of erroneous survey shots At the time Auriga was mostly meant to support Martin s sensor box prototype but it nonetheless of fered a good user interface to manually input survey data and display the resulting line plot Unfortunately computed coordinates were kept internally Auriga offering no list display of any sort In order to start plotting our maps while at camp we needed these coordinates I submitted to Martin a long list of sug gestions for improvement Knowing words are cheap I also proposed help Martin had already received several information requests about Auriga but this was the first help offer Since he had already stopped de veloping his prototype he sent me his source code We had both taken a risk that turned into a successful collaboration the Auriga code base was healthy and well thought out while I was willing to put the neces sary time and energy into the adventure And time and energy it took I decided to make Auriga as universal and user friendly as can be almost everything 15 now configurable often with overridable defaults if appli cable naming format and auto incrementation scheme of survey stations map units length angle and slope 0 refe
7. but the correlation Pot o Gold Cave Compass readings along transverse lines Line 70W a Test 415 107 Line 100W 80 Line 70W 20g fx BN Line 60W 26 5 284 A29 Line 40W TE a n amp O f 180 410 De N oo Line 30W M6 7A ine 20W 10 20 30 40 50 Distance along tape feet is not one to one One dip should be mentioned on Line 160W at 35 N On the approach to a large block fallen from the ceiling a sudden drop of 2 59 was noted Past the block the readings resumed their normal S N decrease Possibly this is direct proof of how remanent magnetism in reoriented breakdown blocks can distort compass readings As mentioned before because magnetite con ducts magnetic lines of force better than air there is a concentration of the field near lava tube walls Be cause of Pot o Gold passage dimensions it was pos sible to document how this concentration affects com pass readings Unfortunately corresponding field strengths close to the walls could not be obtained be cause of the high gradient Note the south end of Lines 130W through 180W In each case as readings were taken about 2 feet from the wall then 5 feet from the wall the compass reading increases The change would probably have been much more had I held the compass right at the wall Corresponding readings could not be taken at the north wall because of prob
8. 885 915 L62 Lec LEC LLb 55 9 Ly 0z 10118 UOoN UuUMOoNO92U9J 58 981 LY 6vkl be 09 b 92 2O9L 69851 98 6991 Gr 891 22 PlGh 26 09S b 60 99947 ZG 09 Sp 99tl 65 6 89 65 98 VS 0651 89 6rEl SL 9 1 96 19 1 SS ALS TIE SS OL b 62 4EC ho L4 SES Li L6 06LL 06 C8LIL 60 Ekk 92 9604 LE gt LZ 186 0L 296 AG 68 6 2287 09 682 98 6 6 Ve 1 906 60 8 9 eL S88 c LV 68 85 5 62 LL ligo Pe LZZ 50 8 1 Sy 55 1 60 S 6 85 L9 9 96 eg ANAL 56 SE V 5 xoxo 62 63 Te xo O 0 O QN 16 10 XO 10 10 t X0 O O NN 0 t t OMONNS Ly c8 55 Cv 58 Z 95 9y OP ig Or AR 1 e tis ial p 26 Sh 6 08 Lv 28 50 91 LS 6 06 euo 2k 199 8l GZ FS BE LG 9 06 ea CS AX ih RE 2 F 8 WA 8 LL rA dpe 8 8 E 68 9 Lg 6L Br a T PAM 92 08 92 iz 0g 4 69 Zk 98 168 tL OZ 91 ES 2 i49 0 8 0 Pe
9. 93 Minimum X 1 13 Y 15 55 Z 168 66 Figure 7 Survey statistics summary screen of surface features like sinkholes or resurgences can be stored into virtual shots looping onto themselves for display in the line plot this allows viewing where the caves heads to relative to these points of interest Viewing the Cave The line plot display offers top and S N W E developed and projected cross section views of the cave with full pan and zoom capability and the ability to graphically poke stations and see the corre sponding survey shot note and station coordinates Hardware buttons can be used to navigate between shots and passages or pan and zoom the view Addi tionally all survey stations linked to another station once selected with the stylus can be cycled through with the push of a hardware button But the most in teresting new feature is probably the ability to get the orientation of a passage the inclination of a slope or the distance between two points by dragging a line with the stylus Orientation angles obtained through this feature are automatically copied to the clipboard to allow quick pasting into the projection angle selec tion dialog for use by the projected cross section view The line plot is probably the most compelling feature to use Auriga underground surveying with Auriga allows cavers to see what the cave looks like and where it heads to right 85 1115 being surveyed Not only can sur
10. City UT 84124 3138 dajgreen burgoyne com In the last issue of Compass amp Tape Vol 16 No 4 Issue 56 the author addressed the causes of magnetic anomalies in lava tubes including 1 A property of magnetic material called susceptibility which causes magnetic lines of force to be diverted away from a void 2 Magnetization of magnetite from lightning strikes 3 Minor magnetization when lava cools below the Curie temperature Mea surements of compass needle deflections internally and externally of lava tubes show that all readings may be in error of a few degrees because of susceptibility effects and in some cases they may be over 10 degrees Errors from magnetization by lightning strikes may cause needle deflections of 10s of degrees Fore and back sights cannot correct for erroneous readings caused by distortion of the earth s magnetic field Part II of this series discusses field observations and surveys conducted by the author Surveys at Pot o Gold Cave Idaho Pot o Gold Cave is the largest lava tube thus far surveyed in this investigation More than any other cave measured it demonstrates how lightning strikes and magnetic induction can adversely affect compass readings Magnetometer and compass azimuth sur veys have been conducted on the surface over all of the lava tubes investigated for this paper They have not been presented because the information they con tain does not contribute much to understanding the anomalie
11. Issue 57 a Pot 6 Gold Cave Entrance Interior Magnetometer Survey S E 5 C o e E EL c lt t 9 c 5 2 gt wo 3 y 5 80 100 120 C Scales in feet Contour interval 500 nt Figure 15 Magnetic field strengths inside Pot 0 Gold Cave every 10 feet starting at the 20 foot mark to avoid the iron gate Readings were taken every 5 feet along the tape except at the walls where adjustments had to be made because of physical constraints Two features on the magnetic field strength map stand out Figure 15 First is the large anomaly at the north end of Line 30W Unfortunately limita tions in the plotting software don t allow proper dis play of the anomaly However the field strength at the north end of Line 50W 20 feet away is 39 000 nt and the 30W anomaly strength is 58 000 nt a differ ence of 19 000 nt This is nearly 2 times the highest anomaly that I have ever measured elsewhere It may even be larger but extremely high gradients prevented full measurements Obviously the cause 1s a lightning strike The second feature is the high concentration of contour lines from the entrance to Line 90W These contours show a decrease of nearly 10 000 nt from south to north 20 of the earth s magnetic field that cannot be simply explained Itis possible that a very strong magnetic low exists to the north A surface resistivity survey has detected a large near parall
12. METIAN POs 8 92 62 19 1 BLAZE JS kk ALLY 65 co 10 10 966 85 9l 69 8 rel 869 LV 09 F EXER 68 oe Sb BAL 55088 15088 OLAN 1819 ALIN 0188 68 68H 8881 8898 S 8M VA A 988 AAM anana AH 9898 Fae ray Say lolB121 8E 8MI 2g8Wl L8H 8 AEYN 9 9 Seve SEVA EVA cove VM UE 58 LENN OF We 0 Y8 6 V M 6 8 381 2 9 8 GEV 92 8 SZYN 95 8 PLAN ELYN 2VH 5 AA A 1 HZVH 2 028 81 6LVY 81 1 289 2 86808960 LN 4T 94 98 SEW SLYS Ph PLM 1 L VM LEV ZYX LEW ns TET ORV 6 6VH 8 8v LYA OW 9 8 9 6 Pe 1 EVM BW OL LYA O0 2NI 9NISV3H 49 31 04 WOMN4 v C Compass amp Tape Volume 17 No 7 Issue 57 Ep pur Uap Eee 51 vont gz EE m 2 lump i SITE ATEI mr eL Dre LU eg 55151 Iunigp 851 mag oul suman Ad l 1 Ol V 5
13. accuracy GPS and digital mapping technology e How to keep cave mud off your survey instruments e How to minimize instrument fogging How to resolve blunders without another trip to the cave How to set and maintain mapping standards in a project Keeping track of survey data in a large project Mapping standards accuracy symbols etc e New and improved computer programs for mapping compare describe critique e New tools and toys to aid in mapping or cartography e Representing complex vertical caves on a 2 dimensional map e Use of computers to draw cave maps techniques pros cons Use of computers to interactively view cave maps views colors rotation perspective The above list is obviously incomplete If you are doing something that you think would be of interest to other cave surveyors please consider doing a presentation on it When you submit your abstract please let the session coordinator Nigel Dyson Hudson know what equipment you will need for your presentation You can assume that the ususal 35mm slide projector or computer projector will be available but don t make any other assumptions Abstract deadline is April 15 2005 Please send your abstracts either by email or snailmail to Nigel Dyson Hudson 10 Slators Lane Newfield NY 14867 nss2005 cavesar com Compass amp Tape Volume 17 No 1 Issue 57 The Effects of Lava on Compass Readings Part II By Dale J Green 4230 Sovereign Way Salt Lake
14. anetic azumith L L d l Lines trend 68 degrees magnetic 150 5 degrees 100 Contour 30 Scales in feet interval Figure 19 Compass azimuths over presumed cavity up flow from Gypsum Cave Solid line is center of magnetic anomaly Fig 19 dashed line is center of azimuth anomaly Reference Mark James and Ernie 9 James Randy members of the Silver Sage Grotto 9 Anderson Moss r S Idaho Falls 5 1973 Applications Manual for Portable Briene 55 Gold 5 assisted surveying the interior of Pot 0 Cave Chris assisted in obtaining the permit This paper was inspired by a communication from Scott Earl 9 Idaho Magnetometers Geometrics Sunnyvale CA concerning wild compass Idaho Cave Survey 9 readings at lava tube entrances 11 Compass amp Tape Volume 17 No 7 Issue 57 Auriga or Trading your Survey Notebook for a PDA By Luc Le Blanc The Auriga software was initially developed in Germany to support an electronic surveying instrument designed by Martin Melzer 1 The software has subsequently been almost entirely rewritten by Luc Le Blanc to become a general purpose package for entering stor ing processing and viewing cave survey data on a Palm PDA Per sonal Digital Assistant In this revised and updated article origi nally featured in BCRA s Compass Points the author describes how the software can be used at present and
15. payable in US and drawn on a U S bank Carol Vesely Secretary Robin Barber 817 Wildrose Avenue 4312 Winding Way Monrovia CA 91016 3022 Fort Worth TX 76126 818 357 6927 cavewoman ev1 net Vice Chair Nigel Dyson Hudson Treasurer Bob Hoke 10 Slators Lane 6304 Kaybro Street Newfield NY 14867 Laurel MD 20707 607 564 7927 301 725 5877 ndh cavesar com bobhoke smart net Editor Patricia Kambesis Hoffman Environmental Research Institue Western Kentucky University Bowling Green KY 42721 ph 270 745 5201 pnkambesis juno com Compass amp Tape Volume 17 No 1 Issue 57 INSIDE Call for Papers 2005 NSS Convention The Effects of Lava on Compass Readings Part II b Dale 2 Auriga or Trading your Survey Notebook fora PDA p An Analysis of Systematic and Survey Errors or Better surveying through Mathematics b Dale AONO siicrsisrririsvcsisprererisevsi seses Front Cover Julie Hudson setting stations in Guess Cave Alabama Photo Alan Cressler Back Cover Map of Maw Rang Naisaw 2 by Stan Allison Blue ribbon in the Novice Section of 2003 NSS Cartographic Salon Permission to reprint material from Compass amp Tape is granted to grottos and other organizations of the NSS provided that proper credit is given Others should request permission from the editor or from the author or cartographers The opinions and policies stated in this publication are not neccesas
16. this are covered in the field called statistics It is assumed that for the random readability errors the errors are distributed normally Normal or Gaussian distributions are illustrated in Figure 1 The height of the line indicates the prob 20 ability of getting that reading The horizontal axis indi cates the deviation from the true reading The careful surveyors get readings that are not exactly the true reading but are closely clustered around it They are almost always within 1 of the true reading The sloppy surveyors are also clustered around the true reading but not as tightly Tlhey have maybe a 5096 change of being within 1 of the true reading but a 5096 change of being more than 1 off A significant fraction of the time there are more than 2 off One way of quantifying the wide of the statis tical curve or the sloppiness of the surveyors 1s the expected error The expected error 1s the level of error within which 50 of the measurements will fall For the sloppy surveyors shown above the expected error is about 1 In all calculations regarding random errors 1 will assume the surveyors are slopped with an expected error of 1 Another way of quantifying the width of a curve or the sloppiness of the surveying is the stan dard deviation For a normal distributuion there 15 a fixed relatinship between the expected error and the standard deviation The standard deviation 15 1 48 times the expected erro
17. 0W to 190W Of these three causes b creates the most problems Effects from magnetic induction a are found mostly in large lava tubes Reorientation of breakdown c can occur in any size lava cave but the effects are relatively minor Fore and back sights cannot correct for any of the above causes of errors They can correct for misreading or misreporting of the compass 1 e read ing 97 but reporting 79 etc Recommendations All members of a lava tube survey team should be aware of sources of compass bearing errors that can affect their mapping The person doing book should be alert to bearings that do not appear to fit the physical cave Above all the instrument reader should avoid taking readings next to walls This last bit of advice may seem impractical because the best station Compass amp Tape Volume 17 No 7 Issue 57 sites are often on walls However if the tape is held taut the compass can be read along the tape at a rea sonable distance from the wall say 4 5 feet Clinom eter readings are in no way affected by magnetic anomalies Instead of fore and back sights itis strongly recommended that two readings be taken at each sta tion spaced about 5 feet apart along the tape This serves not only to correct misreporting the bearing it also gives an immediate indication of the effect that magnetic anomalies are having on the bearing 1115 the best way to determine if the station is near a lightning strik
18. Appendix 1 for doing this Blunders The effect of a single blunder is the sine of the blunder angle times the length of the shot With 2318 feet in 50 shots the average shot length is about 46 22 feet If the blunder is 10 the error is sin 10 times 46 feet or 8 feet This is somewhat more than the ran dom error but still less than even the small instrument error Obviously if there are multiple blunders or single large blunders or ongoing mistakes such as reading grade instead of the slope in degrees these errors will not be small A single blunder of small magnitude doesn t wipe out an otherwise good survey Real Survey Data The above has assumed that all shots are equal in length and in the same line What if they are not To study this problem survey data from an actual cave survey was used This was 50 shots of data from the main passage at Redmond Creek Cave in southern Kentucky This was put into a spreadsheet which 15 included in Appendix II The raw cave data is in the left 5 columns The cave goes generally south from the entrance dropping about 30 feet and then rising again such that is 16 66 feet above the entrance after 50 shots In the error column of the spreadsheet a set of errors was assigned This is a set of 50 numbers with an approximately normal distribution an average of 0 and a standard deviation of about 1 48 actually 1 52 These are typical random errors with an ex pected error of a
19. Compass amp Tape Volume 17 Number 1 Issue 57 Newsletter of the Survey and Cartography Section of the National Speleological Society Compass amp Tape Volume 17 No 7 Issue 57 Survey and Cartography Section The Survey and Cartography Section SACS is an internal organization of the NSS that is devoted to improving the state of cave documentation and survey cave data archiving and management and of all forms of cave cartography Membership Membership in the Section is open to anyone who 15 interested in surveying and documenting caves management and archiving of cave data and in all forms of cave cartography Membership in the National Speleological Society is not required Dues Does are 4 00 per year and includes four issue of Compass amp Tape Four issues of the section publication are scheduled to be published annually However if there are fewer then all memberships will be extended to ensure that four issues are received Dues can be paid in advance for up to 3 years 12 00 Checks should be made payable to SACS and sent to the Treasuer Compass amp Tape This is the Section s quarterly publication and is mailed to all members It is scheduled to be published on a quarterly basis but if insufficient material is available for an issue the quarterly schedule may not be met Compass amp Tape includes articles covering a wide range of topics including equipment reviews techniques computer processing ma
20. Deviation 0 0 Headings V Direct Showor Store Reverse Slopes M Direct Ignore Reverse Altitudes m Dons Save Delete New Noten Figure 2 Session settings screens calibrating instrument sets and shot settings 15 Compass amp Tape Volume 17 No 7 Issue 57 acter set numeric alphanumeric punctuation etc The user can choose between a 4 4 format e g 2 6 or A31 74 and an 8 character free format e g Cascade X24 A6b Both formats allow the use of series a concept inspired by Toporobot A series 1s simply a suite of survey stations and shots sharing a common root like A2 0 A2 2 and A2 31b which can be acted upon collectively As series are usually and appropriately made equivalent to cave passages their use allows users to selectively hide passages from a crowded line plot distinctively color them exclude surface shots from total cave develop ment select the projection direction of a passage in the projected cross section line plot view or just navi gate between passages when reviewing survey shots The sole prerequisite for series 15 to have 8 series beginning survey shot 1 6 a virtual survey shot link ing the series beginning virtual station to the rest of the cave or to itself if it represents the cave entrance The series beginning station must bear the smallest station number within the series e g station 2 3 cannot be the beginning statio
21. Level Done Gave Delete New Note brations measurement units and some default settings see screenshots in Figure 2 The data read from the instruments can then be input as is into Auriga the surveyor 15 not bothered by the broken beginning of his tape the magnetic deviation or the compass shift since the session takes care of these When computa tions are performed Auriga simply uses the proper session settings to interpret the survey data without altering it In this respect Auriga is as faithful as a pa per notebook Tight Storage Despite an effort to squeeze as much survey information as possible into the meager 56 bytes used for each survey shot record in the Auriga cave data bases limits are few Length heading slopes and re verse headings and slopes are each stored with two decimal precision as 16 bit integers 1 6 in hundredths of units Survey shot length is thus limited to 635 55 meters or feet depending on user choice an un common span in caves In addition a note of up to 255 characters can be appended to each survey shot to each session record and to the cave database as a whole Auriga cave databases can currently hold up to a maximum of 16 384 records one per survey shot or session Managing Passages Survey stations can be named with up to 8 characters with user control over the permitted char Session Shots W Gallery Sizes on Bim M Direct Continuous Topofil
22. ase data input up to the point where the usual stylus is not required anymore Figure 4 a context sensitive custom alphanumeric keypad Figure 4 Using Auriga to input survey data underground 15 Compass amp Tape Volume 17 No 7 Issue 57 E Kiamika Heading i H4440 RM Sum Direct 322 0 33220 142 0 O Direet A20 58 noe 1 2 8 12 12 mu o 4 5 e sv 1 2 session2 2 4 4 9 s Pigroom back to entrance uaaa C 0 v ZU BIN J Figure 5 Field data and keypad screens with finger tappable keys was developed for survey data input and navigation between fields see Figure 5 A configurable input Assistant Figure 5 fur ther increases the user friendliness of the whole input process by automatically creating survey shots based on the previous one auto incrementing station names with both digits and letters popping up the custom keypad when necessary preventing mishaps that could result in data loss and even turning off the device after the shot was saved Combined with the use of the hardware application buttons Auriga really lets vour fingers do the tapping A typical fully assisted data input sequence goes like this 1 Start the Assistant mode by tapping its pushbutton in the Survey Shot form 2 Create anew survey shot with the To Do hard ware button a the custom numeric keypad pops up 3 Finger tapin the su
23. bout 1 Note that there are 8 times out of the 50 readings when the error is larger than 2 which implies that foresight and backsight would dif fer by more than 2 The errors were put in arandom arrangement by writing all 50 numbers on slips of papers and draw ing them out of a pile The true z vertical Compass amp Tape Volume 17 No 1 Issue 57 measurements can be found in the True Z column with out taking the errors into account The Error Z col umn is the same calculations with the random error included The difference between these numbers 15 in the Difference column and is the effect of the errors The bottom number in the Difference Column 15 the final error after 50 shots Similarly one can tally up the north south and east west locations of the survey points with and with out the random errors and these are in the 10th through 13th columns One can calculate a total horizontal error which 15 in the right column Again the bottom number is the error after 50 shots The random error column was rearranged 4 times by putting the top number on the bottom and moving all numbers up This gives 5 different sets of random numbers The final errors for each configura tion can again be calculated and the errors are sum marized in Table 2 The bottom row of numbers in Table 2 is for the set of numbers currently in the spreadsheet in Ap pendix II The range of final numbers for z was 6 9 to 2 5 arange of 9 4 O
24. come Send all submission for Compass amp Tape to Patricia Kambesis Hoffman Environmental Research Institute Dept of Geography Geology Western Kentucky University Bowling Green KY 42121 270 745 5201 Email pnkambesis juno com Compass amp Tape Volume 17 No 7 Issue 57 2005 NSS Convention Huntsville Alabama Survey and Cartography Section CALL FOR PAPERS This is a call for papers for the Survey and Cartography session at the 2005 NSS Convention The session is informal and provides a good way to tell other cave mappers what you are doing and to discuss problems related to cave surveying data management and manipulation and cartography Most cave surveyors have either devloped useful techniques that may benefit others or are encountering problems that someone else may have solved In either case an informal session presentation would be appropriate Ho Eee me Jl The session is informal and the audience is friendly There are no requirements to provide fancy visual aids or to provide a written paper other than an abstract to be included in the Convention Program Of course the Compass amp Tape editor would be glad to receive any written papers for publication Presentations can be on any topic related to any aspect of cave mapping and the material presented can be for any level of mapping cartographic experience A partial list of potential presentation topics include e Cave mapping applications of high
25. e from and to points The clino should read O The advantage of this is that you may have some unintentional tendency to read the clino as 0 since this is what you are expecting Another method might be to use 2 points on the same level using a string and a line level to confirm that they are indeed on the same level When doing the clino readings a number of readings should be taken and averaged Statistical techniques can be used to determine the number of readings needed to get a good average I recom mend at least 10 readings The instrument should be read as precisely as possible For example if the 24 reading 15 shy of 0 5 in a real survey you would probably just call it 0 5 When calculating the instrument you should call it 0 4 or whatever you think is appropriate If a survey course is available Use each instrument on the course about 10 times in the same direction preferably using different people As described above don t try to hard to get the best reading The average of these 10 measurements is the reading for that instrument The difference between this reading and the known true reading 1s the instrument offset and it can be added to the in cave survey data One can use the above techniques for both compass and clino If such a course is not available Use the techniques above to calibrate all inclinometers The one compass would be chosen as the master compass Somewhere perhaps ou
26. e algorithm afull blown undirected graph 1s now internally con structed to represent survey stations nodes and sur vey shots vertices between them An iterative algo rithm scans in alternating directions the list of survey shots in the cave database to compute X YZ Carte sian station locations relative to the origin Any station can be manually selected as the Cartesian origin 0 0 0 of the cave or as a location with a user defined fixed offset from this absolute ori gin If the cave does not have a determined origin the computation process chooses the first survey station sorted in alphanumeric order as the origin and as sumes a null offset It is thus possible to assign a pre determined X YZ coordinate to a station presumably computed somewhere else thus allowing the com putation of real coordinates from a cave data subset that does not include the cave origin Likewise any station involved in a zero length survey shot series beginning or virtual shot to which a geographic position 1s assigned UTM or latitude longitude with or without altitude can be manually selected as the geographic reference for the cave The geographic location of any other survey station dis played in the line plot can then be queried for its geo eraphic location Conversely the geographic position Cave Statistics Development 366 6 m Vertical Drop 168 7 m survey Shots 85 stations 84 series 11 Sessions 1 Maximum 51 68 34
27. e anomaly If this does not solve the problem move the station away from the strong anomaly if you Aue NN eem i rs eee pL Re Pig ite es ang 7 Te e r 7 PIDE TET t ga E E D E bE Do TELLITI LLL 31 08uBeui seeJDep g9 pue seur 20 di 60 80 Gypsum Cave Up Flow From Entrance Magnetometer Survey 100 can Also a station located in a strong magnetic gra dient may be made virtual by fore sighting to it from the previous station then back sighting from the next station The virtual station 1s never actually occupied by the compass This works because high magnetic gradients are uncommon and it is quite unlikely that you will encounter two in a row Fortunately errors due to magnetic susceptibilty appear to be fairly ran dom and cancel out to some degree The same can probably be said of reoriented breakdown blocks Acknowledgments Richard C Fox Practical Geophysics Inc Elko Nevada provided the magnetometer Chris Ajsuejur pjey 539 urejqo o JU 00005 PPY 120 140 160 Scales in feet Contour Interval 200 nt Figure 18 Magnetic anomaly over presumed cavity up flow from Gypsum Cave 10 Compass amp Tape Volume 17 No 1 Issue 57 Gypsum Cave Up Flow Area Azumith Survey UC TTG I aet LESER MS ER TRUE HM Re MOS UP E Inge oes Add 50 degrees for total m
28. el tube not far to the north but it is uncertain how this would affect the magnetics here As expected compass readings along trans verse lines show great variation The strong dips at the north ends of lines 20W through 50W are to be expected because of the anomaly What happens with Line 70W was completely unexpected and unex plained A monotonic change of 27 degrees was mea sured in a traverse of 30 feet Any station in this area would have an appreciable error Azimuth variations in each line s southern portion can be explained by large breakdown blocks Transverse lines 110W through 190W are lo cated over a relatively flat floor with occasional large 7 Compass amp Tape Volume 17 No 7 Issue 57 breakdown blocks The azimuths along the lines have comparatively small variations compared to the en trance area Most of them decrease in value from south to north espe cially Line 190W Bearings taken at a station along this line near the south wall would all read about 5 degrees more than bearings taken at a station near the north wall Which reading is right Would tak ing a bearing in the line s center be more correct since its value 1s ap proximately the average of the other two Only a survey independent of a magnetic compass would tell It may be that all readings are off 60 T e Degrees Arbitrary Zero Datum On other lines the dips and rises in azimuth are mainly in areas of breakdown
29. field of electronic data acquisition may well push Auriga into looping the loop by reactivating its serial link with sen sor boxes This would give Auriga an additional boost the prospect of affordable electronic cave surveying may well become irresistible In his article in the De cember issue of the BCRA s CREG journal 3 Mar tin Melzer considers the options for building such an electronic surveying instrument and mentions True North Technology s compass clinometer module 4 as the best commercially available hardware option to date Thanks to Nigel Dyson Hudson who generously lent me his own module I will experiment with it 1n the hope of supporting it in Auriga 18 a b 3 12 1 2 Big room back to entrance A 8B Y 11 08 23 Ca FH B s 112 21m dxz19 m 4 m EN J Figure 8 Poking the Line plot display to obtain dis tance and angular information The ultimate future addition to Auriga will be the ability to sketch the cave walls and details directly onto the Palm screen using vector graphics This may sound like a heresy to purists but a full screen of draw ing space for every single survey shot on a grid dis playing that shot in scale with the surveyor s own vi sual perception would possibly lead to better sketches This feature would definitely render the paper note book useless while allowing cavers to come back to the surface with an almo
30. hrough air The contour map of Figure 14 demonstrates an amazing variation of irregular compass bearings over the area Hardly anywhere on the map can you walk more than 10 feet in any direction and still read the same bearing to a distant target with a magnetic com pass As bad as this condition is the situation 1s worse in some areas inside the cave Inside Pot o Gold Cave a 200 foot centerline was laid out from the gate to a convenient rock Cross tapes were then laid perpendicular to the centerline 150 100 Lines trend 342 degrees magnetic 140 120 100 e Co Lines trend 342 degrees magnetic A 20 Pot o Gold Surface Entrance Area Magnetometer Survey Compass amp Tape Volume 17 No 7 Issue 57 ee pag T AS pA AM dz EE as Ee Tus ca Uy enigi 1 EN tps A x ST IN etes OE f MT eT AW 50 100 150 Scales in feet Contour interval 200 nt Figure 13 Magnetic field over entrance of Pot o Gold Cave Idaho Pot o Gold Cave Entrance Area Azumith Survey Figure 14 100 120 140 160 Scales in feet Contour interval 0 5 degrees Compass azimuths over entrance area Pot o Gold Cave Idaho Add 50 000 nt to get total magnetic field Add 300 degrees for total magnetic compass reading Compass amp Tape Volume 17 No I
31. ibrate the in struments used and of course to avoid major blunders 5 Meticulous matching of foresight and backsight readings beyond that necessary to catch blunders is not worthwhile More work does not mean better results Final horizontal error feet 5 9 coincidentally the first 3 tests gave about the same result 9 23 Compass amp Tape Volume 17 No 7 Issue 57 Appendix I A method of calibrating instruments Some methods are proposed here not yet tested for calibrating instruments These method depends on whether or not a compass course 15 available with true readings known One option is always to simply use the same set of instruments for the entire survey The cave map may be rotated slightly with respect to the true orientation but the entire cave will be rotated the same amount Obviously this 15 not practical in large survey projects A clino can be calibrated against true vertical by measuring horizontally out from a wall and verti cally up from the floor Clearly you don t want to do this in a sagging old bar and even in a new building the floor should be checked with a level The true angle would be the arctangent of the vertical measurement divided by the horizontal measurement This could be compared to the clino reading to give an accurate clino correction Another way to do this would be to measure up from the floor a certain amount at both ends of a hallway to give th
32. ily those of the NSS the Survey and Cartography Section or the Editor Articles and editorials illustrations photos cartoons and maps published in Compass amp Tape are attributed to and copyrighted by the person or persons whose bylines accompany the articles The editor reserves the right to select which of the submitted materials will be used for publication Of the material selected the editor reserves the right to delete redundant or inappropriate material to correct errors of spelling grammer or punctuation and to edit for clarity so long as such alternations do not change the meaning or intent of the author s In the event that signifi cant changes are contemplated the author s will be consulted and given the opportunity to review the changes prior to publica ton ISSN 1074 596 Published in February 2005 by the Survey and Cartography Section of the National Speleological Society Publishing Editor Patricia Kambesis Circulation Editor amp Printing Bob Hoke SUBMISSIONS All types of materials related to cave survey and survey data cartography and cave documentation in general are welcome for publication in Compass amp Tape Manuscripts are accepted in ANY form but are most welcome on 3 5 inch diskettes CD s either IBM compatible or Mac format or via email Typed mate rial is next best although we will accept handwritten material as long as it is legible Artwork is any form shape or size is also wel
33. logged into a text memo for subsequent clean up by the user Otherwise if the beamed records contain a note or passage dimensions and the target device does not have this information while the rest of the record 15 the same records on the target device are simply updated with this additional information The HotSync process takes place on the tar get PC through a conduit launched by the Hotsync Manager This process of synchronizing the Auriga cave databases with those present on the PC 1s a more com plex process than IR beaming for two reasons it runs between heterogeneous databases Auriga and non Auriga and it is a bidirectional process insertions deletions and modifications must be reflected on both sides Itis highly unlikely that any PC cave survey software would have its internal data format match Auriga databases field for field Some software rec ognize series some don t and the same goes for re verse measurements mixed direct and reverse shots mixed measurement units etc Thus in order to trans fer the Auriga survey data to the desktop software the conduit has to adapt this data to a format the tar get software can understand This can mean merging the session calibration with shot data removing se ries beginning virtual shots inverting reverse shots to make them all forward etc In the process some in formation could be lost if the data were to be later resent to Auriga To prevent this information loss
34. n of series 2 if there exists a physical station 2 1 Since series beginning shots are virtual zero length shots the unused shot data storage space in their database record can in stead hold a geographic location like the UTM coor dinates of the cave entrance or an absolute XYZ co ordinate a convenient feature when working with cave subsets Sharing the Data If several teams are let loose surveying a cave conflicts are to be expected with regard to sta tion names or session numbers To circumvent these Auriga offers various maintenance functions to rename or shift station names or series numbers renumber or merge sessions or move survey shots to another ses sion Ideally teams should harmonize their data be fore merging it in order to minimize tedious subse quent clean ups Two mechanisms allow sharing survey data between teams infrared IR beaming and the Palm HotSync process 14 IR beaming is the common Palm OS device to device data sharing mode Auriga can send a whole cave database or a subset of it to another device In the latter case survey shot are nonetheless accompa nied by corresponding sessions so as to make the beamed data complete by itself If the cave database does not already exist on the target device it 1s cre ated and filled with the beamed data Otherwise a record by record merge process 15 triggered Similar but different survey shot or session records are dupli cated and
35. ndom readability er rors are normally distributed as described above certain rela tionships exist among the probabilities of various level of error If there is a 50 change that the error in a single shot is less than 10 there is a 75 chance that itis less than 1 7 and 90 that 15 is less than 2 4 This level of error might correspond to a fairly sloppy survey where foresight and backsight usually agree within 2 sometimes more sometimes less with the true reading being the average of the two readings If there are n shots the random errors will tend to cancel since it is highly unlikely that all the errors will be off in the same direction The more shots there are the greater the tendency for the errors to cancel If there are n shots all of the same length the probabilities for the average error over 7 Surveyed path Surveyed path with bad instrument True Path those n shots are reduced by a factor of error in n shots 1 On times error in 1 shot error If for example n is 50 there 1s a 50 change that the average error will be within 1 050 times 1 which is 0 14 very much better than with a single shot There is a 75926 chance that the average error will be within 0 24 and a 90 chance that the average error will be within 0 34 Table 1 summarizes the J likely errors for a number of shots as Figure 2 Survey paths 21 Compass amp Tape Volume 17 No 7 Iss
36. ne method for estimating stan dard deviation 15 to use the range of data and the num ber of points The standard deviation is thus a fac tor times the range and the factor is based on the number of data points The factor 1s smaller if the number of data points 15 larger This method 15 rec ommended for 20 data points or fewer Arrangement number First V MERGER Fourth Table 2 Errors due to random error T4 9 3 1 bo Final z error feet When there are 5 data points the factor 15 0 4299 giving the estimate of the standard deviation as 0 4299 9 4 4 04 feet The expected error 15 1 1 48 times this or 2 73 feet based on these tests The horizontal errors are generally larger than the vertical errors but not be a large factor The larg est horizontal error in the table above was 9 6 feet This 1s again very small compared to the error from instrument offset Conclusions The conclusions I draw from this work are 1 Assuming there are no major blunders the larg est source of error is instrument error 2 The overall effect of random error is consistently small provided there are a reasonably large num ber of survey points 10 or more This true even if the surveying 1s pretty sloppy 3 Evenasmallinstrument error has much larger ef fect than random readability errors 4 The best ways to improve or maintain good quality survey data are to correlate or cal
37. possibilities for future de velopment In March 2002 before leaving for Mexp our annual 3 week caving expedition in the Mexican Sierra Negra I realized that we would again be per forming the required survey data conversions on our programmable calculator with its antique text mode interface We could indeed run more sophisticated cave survey software on a laptop computer but the closest village is a 3 hour walk away and does not even have electricity Solar recharging works fine in Mexico al though seven hours of bright sunlight are consumed in 2 5 hours of laptop use Could a simple low cost Palm OS PDA powered by two AAA batteries that last for about a month be a viable solution After all we had already designed a spreadsheet to perform basic sur vey data conversions into X YZ coordinates on a Palm A few days before departure Martin Melzer replied to my enquiry posted on the Cavers Digest about the existence of a Palm OS cave survey software I left for Mexico with Martin s Auriga software in my Palm along with two sample caves I was immediately delighted with Auriga It was living proof of the feasibility of a field oriented cave survey software on a Palm device Working in real time software development I was well aware that even a 16 MHz CPU can do wonders with number crunching but in those times of bloated Operating Systems and resource hungry sloppy software I pre viously had no idea where the Palm OS stood
38. pping standards artistic techniques all forms of cave cartography and publications of interest and appropriate material reprinted from national and international publications It 15 the primaly medium for conveying information and ideas within the U S cave mapping community All members are strongly encouraged to contribute material and to comment on published material Items for publication should be submitted to the Editor NSS Convention Session SACS sponsors a Survey and Cartography session at each NSS Convention Papers are presented on a variety of topics of interest to the cave mapper and cartographer Everyone is welcome and encouraged to present a paper at the convention Contact the Vice Chair for additional information about presenting a paper Annual Section Meeting The Section holds its only formal meeting each year at the NSS Convention Section business including election of officers 1s done at the meeting Back Issues SACS started in 1983 and copies of back issues of Compass amp Tape are available The cost is 1 00 each for 1 2 back issues 0 75 each for 3 6 back issues and 50 each for more than six back issues at a time Back issues can be ordered from the Treasurer Overseas Members SACS welcomes members from foreign countries The rate for all foreign members is US 4 00 per year and SACS pays the cost of surface mailing of Compass amp Tape If you need air mail delivery please inquire about rates All checks MUST be
39. r Suppose a passage 15 2318 feet long in 50 equal shots Later we will look at 50 shots of real cave data with a total length of 2318 feet that s why Compass amp Tape Volume 17 No I Issue 57 Expected Error Range 3 2 True reading Figure 1 Normal distributuions the odd number here Assume the are all in the same line to make this easy to visualize The true path 15 represented in Figure 2 by the straight line If the sur veyors are perfect but the instrument 1s off by a cer tain aount the surveyed path will also be a straight lin but will differ from the real path by a certain angle This does not depend on the number of shots or the length of the individual shots If the instrument is perfect but the surveyors are imperfect the measured path will zig zag around the true path sometimes above sometimes below At the last survey station there will be some error ru rum nm E E SE careful surveyors sloppy surveyors Experienced surveyors with whom I have communciated have suggested that instrument offsets are on the order of 1 An instrument offset of 1 0 will continue to propagate and the er ror at the end 15 simply sin 1 times the length of the passsage This will be 1 75 of the length of the passage Fora 2318 foot long passage the error will be 40 feet If the isntrument error is 1 2 the error is 20 feet 3 Ifthe ra
40. r ence Compass amp Tape Volume 17 No 1 Issue 57 computation and display options handling of reverse headings and slopes backsights handling of passage dimensions handling of unsaved data handling of duplicate and incomplete shots hardware button use ince our caving group did not have Martin s sensor box still in prototype state up to this day I concentrated on the manual input side But our need was broader than Martin s single input approach we had to survey a complex cave system with several si multaneous teams possibly with different instruments e g metric tape in small passages and Topofil 2 in collectors using different measurement units e g a Topofil counting in centimetres and bearing different calibrations Of course we would have to merge all this data once back at camp Mixing Instruments Thanks to Sessions The ability to mix heterogeneous data was made possible with the addition of sessions a con cept often found in Windows Mac OS cave survey software Each survey shot belongs to a session 1 e an abstract time period its actual duration is left up to the user during which survey shots are taken Each survey session consists of two sets of instruments cali session Instrumenta e E Dimensions Dimensions Slopes Clinometer Slopes Ois Level Dane Save Delete New Noten session Instruments e Uselnstruments Set 1 for Clinameter Ois
41. raversing Line 40N gives a compass bearing change of 14 degrees in a distance of 80 feet This deviation is due entirely to magnetic in duction not lightning strikes or the com pass needle being attracted to the mag netite While the magnetic field and com pass bearing deviations inside the cave cannot be measured at this time the sur face survey can give an indication of what would be expected if we were surveying an entrance to a chamber with these di Pot o Gold Cave Compass readings along transverse lines 4 Line 190W 0 Line 170W Distance along tape feet mensions Figure 17 Summary Compass bearings can deviate from magnetic north on lava fields because of a Magnetic induction due to the susceptibility of magnetite This causes magnetic lines of force to go around voids in lava b Strong permanent magnetic fields created by lightning strikes These can be very prevalent near lava tubes that exhale air currents Internally mag netic fields from strikes appear to be concentrated along walls Older lava flows show more effects of lightning strikes than younger lava flows do c Reorientation of breakdown blocks that re tained the earth s original magnetic field when the lava cooled below the Curie temperature Reori ented large breakdown blocks affect the compass more than small blocks do Piles of small rocks do not seem to affect readings Compass azimuths for Lines 11
42. revolution htm 5 Auriga home page www speleo qc ca auriga 19 Compass amp Tape Volume 17 No 7 Issue 57 An Analysis of Systematic and Random Surveying Errors or Better Surveying Through Mathematics by Dale Andreatta Questions to be answered 1 What are the relative magnitudes of the 3 common types of survey errors random readability errors blunders and instrument offset 2 Given the results of 1 can we improve our surveying either in accuracy or in speed Random readability errors are caused by hu man limitations when dealing with instruments These errors are usually small and have an equal probability of being in one direction vs the other User bias which is the intentional or unintentional tendency for the sec ond instrument reader to echo the readings of the first instrument reader could be included in random error since there would be an equal likelihood of being off in one direction vs the other Systematic errors are repeating errors caused by small defects in the equipment and are the same for every instrument Blunders are major errors coming from such things as transposing digits misrecording the data in the survey book switching the grade and degrees on the clino reading the compass backwards and others These errors are somewhat random though they don t fall into any kind of pattern the way read ability errors would tend to do Classical Statistical Analysis Situations like
43. rvey data changing fields with the arrow keys 4 When the last numeric field is input the custom 16 numeric keypad changes to an alphabetic layout to edit the survey shot note Edit the note and finger tap the OK button Hit the To Do hardware button to save the sur vey shot a the line plot gets updated and displayed b tap on the Calculator button in the silkscreen area to return to the Survey Shot form Prefs Assistant Auto Popup Numeric Keypad Use Gallery Size Fields Auto Popup Note Keyboard Prevent Unwanted Escapes Confirm Stop Button 2 Wakes up Auriga Current Series Cave Map Keep Backlight On Power Off after Shot Save Auto Length Decimal Sign Vf E L Vf V f Figure 6 Input Assistant configuration screen Compass amp Tape Volume 17 No 1 Issue 57 7 Tapthe To Do hardware button to create a new survey shot a anew survey shot gets created with incremented station numbers b the custom numeric keypad pops up c the Palm turns itself off turn it back on again when ready to input the next shot by hitting the Address Book button Computing the Cave Auriga automatically performs all the compu tations required to display the line plot and essential statistics Figure 7 In order to handle every possible survey shot arrangement like leap frogging or mul tiple shots leaving from or arriving at a station and to pave the way for the upcoming loop closur
44. s found inside the caves However the sur face surveys for Pot o Gold Cave are presented here because they best illustrate an important discovery concerning large lava tubes that exhale air For what ever reason these caves appear to attract lightning strikes In each case of the four large lava tubes with air currents that have been surveyed the area over and around the entrance is peppered with magnetic anomalies that have completely destroyed the signa ture of an underlying void which is usually a distinct linear magnetic low Around lava tubes without air flow lightning strikes are found to be distributed ran domly and never at the entrance Vestiges of the magnetic anomaly caused by the voids of Pot o Gold Cave beneath the surface are at 200E 20N 60N which represents the entrance and at OE 50E 20N Another magnetic low at 20E 20N 40N may be due to a large passage detected by resistivity at this location and a magnetometer sur vey to the west It cannot be entered In addition to the two distinct lightning strike anomalies on Figure 13 the contours over the rest of the map show effects of smaller or older faded strikes These strikes do not appear in the cave directly be neath their surface location In all caves lightning strikes found internally are located along the edges of the tube This makes sense in that electrical currents take the least path of resistance which would be along moist walls rather than t
45. st finished cave map But the complexities of this feature with regards to curve han dling storage and conduit syncing could be the topic of an article by itself Trying Auriga The Auriga Palm software and PC conduit can be freely downloaded from the Auriga homepage 5 along with sample caves embedded help and a 40 page user manual Do read the manual at least once Aurigais not complicated t complex the manual should give you a good understanding of the underlying con cepts and may help you discover features that are not immediately obvious in the user interface Compass amp Tape Volume 17 No 1 Issue 57 If you do not have access to a Palm OS de vice you can nonetheless try the software under a free Windows based emulator Get the details on the Au riga homepage 5 Luc Le Blanc is president of the Soci t qu b coise de sp l ologie References 1 Home page of the original Auriga project home nikocity de andymon hfg auriga4 htm 2 A Topofil is a device using a thread rolling onto a drum connected to a length counter Models made for cave surveying also feature an embedded compass and a protractor to measure the slope 3 Melzer Martin 2003 How to design an elec tronic surveying instrument Cave Radio and Elec tronics Group Journal 54 12 15 Available through Martin Melzer s Web site www melzer ch 4 True North Technology s compass clinometer Revolution module www tntc com Products
46. the conduit performs a two phase sync the Auriga data received through the HotSync manager 15 first stored into a mirror database on the PC before being adapted for the target software This way if the survey data 15 modified via the PC software thus requiring a transfer back to Auriga data consistency between the PC and Compass amp Tape Volume 17 No 1 Issue 57 the Palm must be maintained if further surveying with Auriga is to take place in that cave the conduit can fetch from the mirror database the previously dropped data and re attach it back to the synced records be fore writing them into the Auriga database Of course the extent of this data removal and recovery depends on the target software some being more restrictive than others And to support the multiple survey teams mode the Auriga conduit structure supports both the usual single user mode and a multiple user mode where several users can collectively sync their data with the same cave database The current Auriga conduit developed by Chris Ch nier can export Auriga data as either Com pass or Visual Topo files Chris is now working on implementing the import by Auriga of existing cave sur vey data from these same software allowing the ex change of data between the Palm and the PC so one can take advantage of both environments The XML based data conversion grammar used by the Auriga conduit makes it easy and quick to add support for other cave survey software
47. tside the cave entrance a FROM point and a distant TO point would be chosen The FROM point might be a tree and the TO point might be a distant power pole Obviously the FROM point should be well away from magnetic fields and metal objects and both points should be points that will be around for a while The above procedure with 10 readings would be used and the average recorded In the future any other compasses were used they would be run through the same test with 10 readings of that instrument The difference between this average and the average from the master instrument would be the offset for the new instrument This technique might give a cave map that was rotated from its true orientation but it should all be rotated by the same amount Compass amp Tape Volume 17 No I Issue 57 96 08 69 99 SA 8k 957 99 9 9y TFS 00 8 aye 05 06 LG 60 057 pm LZ 64 06 65 8 OF L 9 bs 8 89 ec So 60 61 v 6 6 T15 FA 61 g g6 95 LEE cS ID Peg AL be 05 TTT ND X0 X0 XO XO 16 M xb CO c 00 Q QI QN 5 00 NL 10 10 40443 14 0 11 3 1 D E F ee 2 00 01 v 118 LARA EZ 96 00 vs LL amp 8 84 681 9 0S
48. ue 57 50 chance of average error within 90 chance of average error within 75 chance of average error within 0 76 0 158 0 158 Table 1 SLummary of expected errors suming that there is a 50 change of a single shot being within 1 For the case where you have a 2318 foot passage in 50 shots with the sloppy surveying de scribed above at the end of 50 shots your average error is 50 likely to be within 0 14 The error in height would be 2318 sin 0 14 2 5 66 feet much smaller than the 20 feet of error one gets with even 1 2 of instrument offset The more points the higher the accuracy how ever you have to have a large increase in the number of points to have much effect One caver I know al lows no shots longer than 50 feet Adding a few more shots probably doesn t help the accuracy much es pecially since random error is so small compared to instrument offset There may be other considerations which say not to allow shots longer than 50 feet One might want to have more cross sections and longer shots tend to leave the sketcher falling behind One might think that if the instrument offset 1s less than the readability of the instrument then the off set must be negligible and shouldn t be worried about The above numbers say that this is not true One might also wonder how to correct for instrument offset to an accuracy better than the readability of the instrument A technique will be presented in
49. vey errors be detected faster but it can orient the exploration process by knowing right away 17 Compass amp Tape Volume 17 No 7 Issue 57 where passages head to surveyors can decide which lead to survey in priority If 8 connection 15 expected Auriga can let cavers know immediately how close they are from the other passage and eventually keep hope Actually Auriga could become an incentive to survey while exploring a good practice in every re spect And thanks to Markus Dresch PalmSide s XPrint Library granted free right of use to Auriga the line plot can now be sent right from the Palm to vari ous PCL ESC or Postscript enabled printers via the built in serial infrared or Bluetooth link Auriga also offers spreadsheet like displays of survey shots and survey station coordinates to pro vide surveyors with the coordinate data required to draw their cave maps on paper while at camp These lists are also printable What s Next The display of passage widths 15 currently in the works as well as loop closure and the introduc tion of the cave system concept where several caves can be logically linked and geographically positioned on a common display Other minor improvements include theodo lite and depth meter logic to handle cave diving survey data and better statistics Of course the recent presentation at the 2004 NSS Convention may prompt unforeseen new demands Meanwhile the rising activity in the

Compass & Tape - National Speleological Society

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Compass &amp; Tape - National Speleological Society

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Compass & Tape - National Speleological Society