GIS Web Mapping
Contents
1. 6 Web Mapping 7 Classification of web mapping 7 Architecture of Interactive mapping 7 Data types 7 Web server 8 Tiling 8 Open Geospatial Consortium 9 Web Map Service 9 OGC WMS2. 9 EPSG 10 OpenLayers 10 Client side 11 OL library 11 Web map application 11 Google Yahoo Bing and other APIs 11 OpenLayers Layer 12 Map Controls 12 Controls in detail
3. 23 Web administration interface 23 Server 23 Data 23 Layer group 24 Services 24 Tile catching 24 Map projections 24 Introduction Data sharing and distribution over the internet may seem to be difficult and expensive for persons representing e g NGO s or local folklore societies etc There is still an increasing need to share their data to the public For example statistical geospatial data are difficult
4. 13 Web page design 13 Geoserver 14 RESULTS 15 Detail explanation of Script 17 CONCLUSION 19 Problems during project 20 Future work 20 ACKNOWLEDGEMENT 20 REFERENCES 21 APPENDIX 1 GEOSERVER INSTRUCTIONS
5. The OpenGIS Web Map Service Interface Standard WMS provides a simple HTTP interface for requesting geo registered map images from one or more distributed geospatial databases A WMS request defines the geographic layer s and area of interest to be processed The response to the request is one or more geo registered map images returned as JPEG PNG etc that can be displayed in a browser application The interface also supports the ability to specify whether the returned images should be transparent or not so that layers from multiple servers can be combined When a Web Map Service fulfills the WMS specifications of the OGC it is referred to as an OGC conforming WMS This means that requests to and responses from the WMS must be done according to a specific standard The following three queries fall under current OGC specifications with the third being optional 1 GetCapabilities queries the WMS capabilities 2 GetMap requests a specific map 3 GetFeatureInfo requests information on individual map objects The figure below illustrates the relationships between some OGC web services as well as the main operators as defined by the OGC web services Figure 3 OGC Web Services Architecture Hazzard E 2011 EPSG Geographic coordinates describing the position of an object on the earth s surface refer as an earth model rather than the Earth itself There are many ways to represent objects in the model with different coordinate
6. challenging as it related to IT technologies which makes little difficult to understand the tools and work on them Future work In the current web map application it is not possible to see the details of the data that are displayed on the map It will be much better if the user can select any data on the map that display its attribute information It will be more advanced application if there is possible to add data directly on the application instead of installing another geoserver or sending data to Stockholm university department Acknowledgement Firstly I would like to thank my supervisor Goran Alm Senior lecturer at Stockholm University for his guidance during the project I would also like to specially thank as a co supervisor Stefan Ene GIS developer and teacher Stockholm University for his guidance to figure out technique problems I want to thank Rolf Jacobson Webmaster at Stockholm University who shares his valluble thoughts to develop the results of the thesis I want to thank my examinor Peter Schlyter Senior Lecturer at Stockholm University for giving shape to my views Finally I am expressing my heartiest gratitude to all of them References Carver S Evans A Kingston R amp Turton I 2005 Virtual Slaithwaite A Web Based Public Participation Planning for Real System Retrieved 06 24 2013 from School of Geography http www geog leeds ac uk papers 99 8 1 Directions Staff den 29 October 2009 GIS Web Map
7. server When the user interacts with the map by panning zooming or looking at a particular area on the map the client should request that particular map from the server and display it on the map OL does all client work by using asynchronous JavaScript AJAX Web map server A map server simply provides maps to the web map client There are many different map servers that are available WMS examples are Google Maps Bing Maps Yahoo Maps etc these map servers allow the client to select different parts of the map With OL it is possible to use multiple back end servers like Yahoo Google Bing etc Google Yahoo Bing and other APIs Google Yahoo and other APIs provide their map service on the map objet as background map OL does the same These APIs works on client side like OL Google maps are very powerful which can allow GIS tools on the map which can also be done with OL The biggest disadvantage of using Google is there will be no access to its backend server As there is not possible to access the backend server there is high rick that something can happen in Google server To solve this problem OL recommend downloading the OL library and save it locally instead of accessing it from OL server OpenLayers Layer As mentioned earlier OL allow multiple map servers or backend map servers that can deliver data to the map These different map servers will be added to the map as layers using OL Each layer on the map will add on top of each
8. the Swedish projection system will be shown In Swedish projected map data includes a background map from lantmateriet So there will be only data layers without any background map like Google Maps Other map can be shown by pressing the button Show Hide data on World Map Data projected on the world map were semi transparent in order to see the background map to know the difference between the past and present User can see both maps on the page or can hide one by clicking on buttons on the web page On the right side of the page description of the data has been given in Swedish target people on this project are comfortable with Swedish language Finally the biggest challenge of the project is to animate the layers in a series to show how the land has been raised and this was done by using the Giff animator tool Layers were imported to the Giff animator in order 5000 BC to 1500 AD and produce animated Giff image The animated image has placed in the server and displayed with HTML tags The HTML script that has used to create the web page can be shown in Script Figure 6 Screenshort of the designed web map application Result Detail explanation of Script The web map application is designed by using HTML CSS and Jquery In this section a detailed explanation of the script will be given lt div id map style height 500px width 500px float left gt The above block tag will create the Map Object on the web application I
9. to understand if it is presented as tables or graphs The users understanding can be improved by showing the data on a map The process of showing data on a map over the web is termed as Web Mapping or Internet Mapping Showing the data on a map requires geospatial coordinates of the data The use of internet mapping has been getting vast popularity for past few years By the end of 1999 there were about 40 million maps were produced over the Internet per day and two years later almost reached over 200 million per day Sch tze 2007 This tremendous increase of the use of internet mapping shows the importance of showing sharing spatial information over internet On February 2005 the release of Google maps created a revolutionary change in the concept web mapping Google maps were introduced with dynamic mapping with more user interface tools that made it successful Ramsey Continues development of GIS technology and in special web mapping can provide smart and self service applications Municipalities in England has successfully implemented web mapping applications to improve the citizen services and recognize savings Directions Staff 2009 Web mapping applications come with menus and functions easy to understand and users can browse or search for information through the web The level of information provided can be varied according to the intended user and the access to data can be regulated through the use of login and password if s
10. L works on the local machine of the user it particularly runs on the user s web browser OL library OL is a Java script library which is developed by a group of brilliant people and can be either downloaded from the OL website or accessed from the repository on the OL website www openlayers org OL library is an API Application Programming Interface which provides tools to build web mapping applications When a web mapping application is made from scratch mapping part of the application can be used from OL library For example if you want to setup a blog it is not necessary to build it from scratch instead existing sources like WordPress or Blogger can be used to build an application on top of it The same for web mapping it can be created from scratch or use examples from the OL library which has been built and tested by a strong community Web map application Web map application could simply be any application of internet that uses maps For example showing the population density in different regions of a city on map which are geo referenced or it could be showing water bodies geo referenced on a particular area in a map Figure 4 Server Client model Hazzard E 2011 The core process of any web application called Server Client Model In the case of web mapping OL acts as a web map client which request map data from the map server E g WMS server Web map client The primary duty of the client is to get a map from the map
11. Master s thesis Physical Geography and Quaternary Geology 45 Credits Department of Physical Geography and Quaternary Geology Implementation of a Geoserver application for GIS data distribution and manipulation Karteek Kommana NKA 79 2013 Preface This Master s thesis is Karteek Kommana s degree project in Physical Geography and Quaternary Geology at the Department of Physical Geography and Quaternary Geology Stockholm University The Master s thesis comprises 45 credits one and a half term of full time studies Supervisors have been G ran Alm at the Department of Physical Geography and Quaternary Geology Stockholm University and Stefan Ene Department of Human Geography Stockholm University Examiner has been Peter Schlyter at the Department of Physical Geography and Quaternary Geology Stockholm University The author is responsible for the contents of this thesis Stockholm 12 June 2013 Lars Ove Westerberg Director of studies Abstract Accessibility and Interactivity are keywords of information today and that is equally important in science as anywhere else When scientists share information it benefits if it is intuitive informative and simple and does not demand expert skills in complicated formats This master thesis has the aim to investigate open source software tools to design a web map application that can be used by any institute or NGO to distribute their data over internet The Java platfo
12. any institute or NGO to distribute their data over internet The case study that was undertaken shows clearly that it is possible to share spatial data with minimum technical skills and low or no cost In the case study the performance of the web map application was tested with raster and vector data to compare its performance Raster data requires little more time to fetch data from the map server than vector data Raster images used in the case study are high resolution and have large size around 250 MB each layer gives decent performance which shows that the application can be used for sharing even high resolution satellite images In the case study data was displayed on both Google Maps and as a map specifically for Swedish data using SWEREF99 TM projection The reason for using Google Maps is its popularity worldwide There are four different Google base maps Google Hybrid Google Streets Google Physical and Google Satellite User can select anyone in the list for better understanding and if the layers are half transparent it is possible to see the background map though it Data that needs to be projected on the Google Maps should be prepared in WGS 84 projection system On a Swedish specific map object data that have a Swedish projection system can be superimposed Data on both maps objects are pannable zoomable and select unselect on the layer list over the map object The animation was done earlier at the department u
13. are instructions for installing geoserver on a standalone machine 1 Download the geoserver application from their website www geoserver org You need to select the latest version which will usually be on the top of the list 2 After downloading follow the instructions for installation 3 During the installation you need to select the type of installation as Install as service which makes it run on the server 4 Geoserver runs default on port 8080 It is possible to change the port according to the user requirement It is important to know that two geoserver applications cannot run on the same port they must run on different ports 5 Default credentials for geoserver are admin and geoserver It is highly recommended to change the password for the reason to avoid others to login and change or delete the data 6 After successful installation geoserver is ready to use Web administration interface This is the place where you will do the entire configuration for geoserver including importing data editing layers delete layers etc This web administration can be accessed via a web page which is by default localhost lt port gt geoserver web The port number can vary according to the user need You need to login with the credentials to access the administration page After successful login to the page you will see different sections on the left side of the page which will be briefly described below Server In thi
14. cation of web mapping Web mapping is divided into static and interactive maps Static maps are simply mapped pictures that can be fit into the web page with no user interaction whereas interactive maps are more advanced maps which allow users to interact with the data on the map The only interaction that the user can have in static maps is panning around the map which does not alter anything on the map Architecture of Interactive mapping Map object on the web page communicate with the web server to display data on the map which are stored on a web server For example when the user is zooming in the map the map client requests map tiles from map server and are displayed on the map The server will generate new maps corresponding to the zoom level The newly generated maps will be sent to the map object and the web map client displays it on the map that is integrated in the web page The picture below shows the architecture of web mapping Figure 1 Client Server Architecture Mitchell 2005 Data types A web browser can usually be able to display various types of raster data on the map in PNG or JPG format but browsers are still not able to support a variety of vector formats Web server A web server is the place where map data are stored It is usually installed in a separate machine Popular free web servers include Geoserver Tomcat MapServer etc Later in the report we focus on Geoserver which is used especially to store Geo referenced da
15. ent and government as well as government and NGO s Montagna 2005 The use of web map applications is increasing in both public and private sectors These web based GIS projects often face challenges like lack of financial resources lack of technical expertise and lack of documentation about how non technical users can make use of web based GIS It is difficult to evaluate whether these advantages of technology can really lead to the improvements suggested by their proponent s improve public participation transparency in government literacy in Web GIS better data driven decision making by community based organizations In recent times use of internet has improved greatly with no doubt geospatial information has become a part of people s day to day life Online street maps like Google maps Google Earth and Yahoo maps are popular and are combined with social networking sites like blogs wiki personal publishing This trend has increased in recent times One popular site states that it has more than 40 million unique visitors per month Nivala Brewster amp L 2008 which clearly show the popularity of web mapping technology in the public The biggest advantage of adapting web for developing applications includes 1 No local installations required 2 Automatic upgrade of new features for all users 3 Worldwide access from any device connected to the internet The aim of this project is to see if it is possible to design a web map ap
16. ge as HTML lt html gt starting the script with All the script lies under this tag Beginning tag lt body gt content of the page resides under this tag Beginning tag lt h1 gt My First Heading lt h1 gt this tag is for heading on the web page Both tags lt p gt My first paragraph lt p gt this tag is for a paragraph on the web page Both tags lt body gt this tag in the script closes the beginning tag lt body gt Close tag lt html gt this tag in the script closes the beginning tag lt html gt Close tag CSS standards for Cascading Style Sheet It defines the style of HTML objects on the web page Using CSS it is possible to display or adjust the position of different objects like table paragraph heading copyright etc on the web page A simple style for a paragraph in a web page below W3Schools CSS Tutorial lt p style color sienna margin left 20px gt This is a paragraph lt p gt Defines color of the paragraph It defines the paragraph should be 20 pixels distant from the left margin JQuery is a client side JavaScript library that can be used to create dynamic web pages With JQuery it is possible to navigate to the web page and to e g create animations on the page The simple JQuery script shows below document ready function p click function h1 css background color red When user click on the paragraph on the page JQuery triggers backgro
17. generate tiles instead it will use the already generated tiles that are stored in Tiles Layer section Map projections It is possible to use different projections for different countries This feature will help the user to display his data on specific projection It is possible to create EPSG projections and use that projection when tiling the layer
18. hitepapers mashups mashups den 24 06 2013 Risberg J Alm G amp Goslar T 2005 Variable Isostatic Uplift Paterns During the Holoene in Southeast Sweden Based on High Resolution AMS Radiocarbon Dating of Lake Isotopes The Holocene 847 857 Sch tze E 2007 Current state of technology and potential of Smart Map Browsing in web browsers using the example of the Free web mapping application OpenLayers Sch tze E 2007 Thesis Smart Map rowsing H mtat fr n http www smartmapbrowsing org html index_en_9 html webmapping_tiling den 24 06 2013 Sch tze E 2007 Web Mapping H mtat fr n Smart Map Browsing http www smartmapbrowsing org html index_en_9 html id7 den 27 06 2013 W3Schools u d CSS Tutorial H mtat fr n W3Schools http www w3schools com css default asp den 24 06 2013 W3Schools u d HTML Tutorial H mtat fr n W3Schools http www w3schools com html default asp den 24 06 2013 W3Schools u d JQuery Tutorial H mtat fr n W3Schools http www w3schools com jquery default asp den 24 06 2013 Appendix 1 Geoserver Instructions Note Before installing the geoserver you have to install JRE on the server the reason for this is geoserver runs on the Java Runtime Environment JRE Without this geoserver will not work Geoserver can be installed on a physical server or as a virtual server Geoserver is used to store layers on the server in order to make them available on the internet Here
19. ically but can be seen by selecting on the layer list over the map object In the above way all the layers were created Then all the layers need to be added to the map object This can be done using the block script below map addLayers wms_layer_5000_fKr wms_layer_4500_fKr wms_layer_4000_fKr wms_layer_35 00_fKr wms_layer_3000_fKr wms_layer_2500_fKr wms_layer_2000_fKr wms_layer_1500_fKr wms_layer_1000_fKr wms_layer_500_fKr wms_layer_0_Kr wms_layer_500_eKr wms_layer_100 0_eKr wms_layer_1500_eKr wms_layer_Point_Data map addLayers will add the created WMS layers to the map object After adding the WMS layers to the map object it is possible to create controls on the map for user interaction with the map For example scale on the map can be created like below var scalebar new OpenLayers Control ScaleLine Tip in the traditional desktop GIS tools top layer on the list will be visible on the map but in case of OpenLayers it doesn t follow such rules There is a way to define the layer order by defining a control to layer list as below var layer new OpenLayers Control LayerSwitcher ascending false map addControl layer by setting the ascending false the top layer on the layer list always appears on the map other layers will be added below it Conclusion The aim of this project is to investigate open source software tools that can be used to design a web map application that can be used by
20. ld Pan zoom bar can be used to pan the map in any direction and the zoom bar can be used to zoom the map from global to local level Layer overview of the map allows the user to select the specific data on the map which will be very useful to compare different data on the map GIS tools can also be added to the map in the tool box which will allow the user to create points lines or even polygons on the map For a more advanced web mapping Ajax has been used to connect the map with the other objects on the web page Web page design In order to build a web page some basic things are required 1 Page construction e g HTML 2 Styling e g CSS 3 Page interaction e g JQuery HTML is the standard and universally accepted markup language used to construct the web page HTML stands for Hyper Text Markup Language HTML defines the structure of the web page using standard tags which are enclosed in angle brackets e g lt html gt and attributes All the HTML tags are coming up with pair i e beginning tag and ending tag lt html gt lt html gt The closing tag looks exactly same as beginning tag with extra back slash before the tag name There are several hundreds of HTML tags are available in the language all the tags are not required to construct a web page Two basic tags are necessary to construct a web page web without those pages cannot be build W3Schools HTML Tutorial lt DOCTYPE html gt this tag defines the pa
21. n auto projection EPSG 3006 units m isBaseLayer false visibility true var map new OpenLayers Map map controls In OpenLayers to create a new object you need to say var before the object name on the left side followed by the name of the object need to be created This is the OpenLayer code to create map object on the web map application Name of map object It can be anything not necessarly map This is the control secton for map object Controls means apply default controls to the map var wms_layer_0_Kr creates a new WMS layer wms_layer_0_Kr newOpenLayers Layer WMS defines that the object created will be a WMS layer that can be displayed on the background map This is the Java script to add WMS layers on the map object on the web map application The layer name is the one that can be seen on the layer list on the map object It is possible to give any kind of name to the layer depends on the user interest and the data type Each layer on the geoserver has a specific address for easily identification and it is not allowed to have the same address for more than one layer When a WMS layer is imported to the goeserver it is necessary to give it a unique name It is possible to assign different properties to the layer Transparent true means the WMS layer is allowed to make transparen
22. nfiguration in northern Uppland southeast Sweden 17 overgrown lakes have been interpreted by diatom analysis and AMS radiocarbon dates on terrestrial macrofossils Also 20 archaeological sites expected to be shore bound were dated and their locations measured The sites studied are spread c 60 km in east west and c 70 km in north south direction From these 37 sites a multi linear regression was performed and used to determine the expected elevation of the Baltic shoreline for a given age and a given position in the map coordinate system The data analysis showed that the rate of isostatic uplift was faster the further to the north you are and faster the further back in time you look The radio carbon dating of the archaeological and lake sediment samples were between 5000 BC to 2000 BC As a result from the analysis it is possible to produce maps of the position of the shoreline from a given age so called paleogeographic maps A set of maps separated by 500 years from 5000 BC and extrapolated to 1500 AD were constructed These maps are now used to illustrate the web map application in this exam project work Risberg Alm amp Goslar 2005 Web Mapping Presented Spatial data as a map over the internet is termed Internet Mapping Web Mapping net based etc showing data on the map over the internet is not only a simple web mapping along with presenting the data it should also provide simple tools like zoom bar and panning over the map Classifi
23. nizations and universities all over the world The major objective of the OGC is to develop international standards for geospatial data and to set standards for public use OGC standards come with a technical documentation and encodings OGC and OpenGIS are the trademarks of OGC standards The standards allow the developers to create complex spatial information and make it accessible to public and can be useful in different kinds of applications Open Geospatial Consortium Web Map Service The fundamental component of web mapping application is its map image The Web Map Service shortly as WMS is the standard process of accessing map data from the server where map data are stored When user interacts with the map map tiles will be generated on the server and be sent back to the map WMS generates map data in the form of image whether it is a vector or raster data A simple WMS request can look like below http localhost 8080 geoserver topp wms service WMS amp version 1 1 0 amp request GetMap amp laye rs topp tasmania_cities amp styles amp bbox 145 19754 43 423512 148 27298000000002 40 852802 amp width 512 amp height 427 amp srs EPSG 4326 amp format image png A quick explanation of the above WMS is 1 Server details a WMS 1 1 0 request 2 Request type WMS GetMap 3 Layer name topp tasmania 4 Projection EPSG 4326 5 Bounding box in this case latitude longitude coordinates 6 Image size and format 512x427 PNG OGC WMS
24. nside this div element Java scripting was written using OpenLayers library When creating the map object it is required to define the map controls There are two ways to define controls to the map object one way is to give basic default controls to the map object controls like zooming and panning around the map The second way is to define user specific controls to the map only controls that are defined will apply to the map object In this project map object were given default controls in the beginning to make sure that it contains minimum controls and later specific controls were defined like Scalebar Panel Layer Mouse Position etc map object with default controls can be created like below Note it is very important to keep an eye on comma colon and apostpie in the script They are very important and without them the script won t work After the map object created layers need to be added to the map There is no limit to the number any number of vector data or raster data or even both together can be added to the map Similar like creating the map object layers follow the same rules as below For better understanding the script was written in different rows var wms_layer_0_Kr newOpenLayers Layer WMS 0_Kr http 130 237 175 39 8080 geoserver wms land_upplift layers 0_Kr transparent true format image png maxExtent new OpenLayers Bounds 585000 6600000 740000 6722500 maxResolutio
25. o desired With easy access to information via the internet there has been increased participation from the communities on issues relating to community Majid Haron amp Rafee 2007 With the introduction of Google Maps and Bing Maps people are exposed to the GIS solutions in their smartphones tablets and computers This widespread use increases the familiarity of reading information from web maps Municipalities using this web map technology have the tool to provide and spread large quantities of information online This gives citizens 24 7 access to information which vastly reduces phone calls to government offices Some of examples of map services that government agencies provide are 1 A web map application that can be used for crime complains by pointing location 2 Providing information about the construction projects that are ongoing which can cause traffic delays Through web map service users can also process and manipulate spatial data online such as doing simple analyses using the spatial data This analysis can be done by customizing the user interface with simple analysis functions One example is the Slaithwaite Web GIS Carver et al 2005 which provides the community with markup functions on the web that lets the user to comment on the data directly on the map In planning web mapping applications can also support the concept of e governance through the internet the two way interactions between government and citizens governm
26. other just like the desktop GIS applications Google or Yahoo map servers etc can be used as background maps and on top of it any kind of raster or vector data can be displayed The advantage of using vector data is that it allows user to add GIS tools to the map on top of it Map Controls In general a simple web map should have the following components Main Map This is the major component of the map On top of the map raster or vector data can be projected Overview Map It s also a main map but with navigation window It will act as a reference map The zoomed portion of the main map can be seen on the whole map with a rectangle box highlighted the zoomed area Pan Zoom Bar It is a zoom slider to select the zooming level of the map Layer Overview This portion of the map contains the data present in layers Layers can be selected or unselected here Toolbar This portion of the map contains GIS tools like panning button zoom button etc The tool box can be placed on the map or outside the map Scale Bar Scale bar shows the current scale of the map Figure 5 Components of Web Mapping Application OpenLayers Sch tze Web Mapping 2007 Controls in detail With the rapid growth of the internet and web mapping the concept of map interaction has gained greater importance In modern web mapping applications user has more specific interactive tools on the map It is possible to display data on the map in any region of the wor
27. ping Enables Self Service and Savings EPSG 2012 Geomatics Guidance Note number 7 part 1 OGP Publication Geoserver u d Geoserver User Manual H mtat fr n http docs geoserver org latest en user den 24 06 2013 Hazzard E 2011 OpenLayers 2 10 Hazzard P 2002 Web Map Service Implementation Specification H mtat fr n http portal opengeospatial org files artifact_id 1081 amp version 1 amp format pdf den 24 06 2013 Majid Haron H W amp Rafee M 2007 The Use of Web GIS Among Local Authorities A Survey of the Contents and Level of Services Kuala Lumpur Dept of Urban and Regional PlanningUniversiti Teknologi Malaysia MapQuest 2007 MapQuet H mtat fr n http www mapquest com den 24 06 2013 Mitchell T 2005 Web Mapping Illustrated Sebastopol CA USA Oreilly amp Associates Inc Montagna 2005 A Framework for the Assessment and Analysis of Electronic Governament Proposals Electronic Commerce Researh and Appliactions 4 3 204 219 Nivala A M Brewster S amp L T 2008 Usability Evaluation of Web Mapping Sites The Cartographic Journal 129 138 Open Geospatial Consortium n d Retrieved 06 24 2013 from About OGC http www opengeospatial org ogc Peterson M P n d Webmapping at the start of the new millennium state of art 3 17 Ramsey P u d Mashing up the Enterprise H mtat fr n http www refractions net http www refractions net expertise w
28. plication by using open sources so that the end user does not need technical skills to work with it The outcome of this project will in that case be a web map application that can be used by any institute or NGO The data of any individual person can be shared over the internet with no or low cost and with only basic technical knowledge Objectives The specific objective of this project is to design a web based mapping application suitable for a university department or NGO that should be able to 1 Supply maps from the research activities to the public 2 Supply maps to the restricted users e g other research groups different organizations 3 Data on the map should be selectable editable zoomable pannable etc on Google Maps 4 Animate the map layers of an application 5 Users own data should be possible to superimpose on the map object in the application 6 To validate how useful is a system like this for e g NGO s and other local society or private person To test suitable methods for implementing the above objectives an already existing data set was used This data comes from an earlier project at the department and it deals with the effects of a change in shoreline due to the isostatic uplift that has its origin in the melting of the ice cover over Scandinavia during the last stages of the last glaciation and is briefly discussed below Case study The Land Uplift To describe change during the last 7000 years in shoreline co
29. rm to be implemented is the open source OpenLayers which allow users to view and potentially manipulate GIS map data through a web map application Whatever GIS data made available on the Geoserver the host site for the application can be shared to users worldwide The user can then add from a list of available data layers choose background e g Google Earth Open Street Map etc zoom in and out pan change symbols and colors add their own data on top and start animation if applicable The data distributed from the Geoserver can also be viewed and accessed from smartphones which opens the possibility to make the public part of the larger data gathering task of specific scientific inventories like observations of migrating birds or whatever indicator a specific scientist is interested in Data is uploaded to the Geoserver and can then be analyzed and the result is distributed to the public Keywords OpenLayers Java Geoserver Table of Content ABSTRACT 1 INTRODUCTION 5 Objectives 6 Case study The Land Uplift
30. s The European Petroleum Survey Group EPSG designed a model with geodetic parameters in 1985 for internal use in their company In 1995 they make the data public to their Petro Technical Open Software Corporation data model In 2005 EPSG was reformed to the International Association of Oil and Gas Producers OGP OGP is a group of companies working on exploration and mining world wide The dataset includes coordinate systems datum transformations projections units and other related information The information was gathered from various petroleum companies government agencies that are responsible for geodetic in that specific country EPSG dataset is available for free download and are worldwide accepted coordinate system and transformation information Data will be frequently updated at least 2 6 times in a year depending on the data they get EPSG 2012 OpenLayers OpenLayers OL is a Java script library running on the client side It is completely open source and can be freely accessed Having programming knowledge will make it easier to work with OL but even non programmers can be able to handle it as everything is stored in the OL library It is not owned by any company and it is been developed by group of developing communities It is possible to download the Java script library locally or on the server and edit the library according to the user need It works in almost all the modern web browsers and some older like IE6 Client side O
31. s section there will find information about the configuration tools for geoserver contact information for the public in a WMS capability document and importantly this section will use for debug the server problems Data Here you have the possibility to add data to the server First you need to create a work space to store the data In case of large data it will be very useful to have a separate workspace for different data In geoserver there is a possibility to store three different types of Geo data vector raster and WMS There is also a possibility to connect PostGIS database to geoserver In this project we will be discussing extensively about vector and raster type data and more specifically in vector type our focus will be importing shape files There is a specific procedure to import data into the geoserver which will be described below 1 You need to create a workspace for your data Give it a suitable name which should make sense It is recommended to separate the data by storing them in separate workspace to avoid confusion in the longtime 2 Data will be imported into geoserver by creating a store A store can be a vector raster or WMS 3 After adding the data it is possible to preview the data on a map using the Layer preview option To do that go to layer preview on the list of the lawyers find your layer and press on OpenLayers to see it on the map or you can download KML format of the data to view it on Google Earth La
32. sing the Gif animator tool The animation provided on the web map application was taken from the department site http ww2 ink su se living_maps For the specific users who want to superimpose their data on the map object in the application this can be done in two ways Data can be sent to the Stockholm university department where data will be superimposed by them or the users need to install the geoserver software open source and run it on his her own computer After the successful installation of the geoserver data need to be imported into it Users are able to run the web map application on their own server by adding their data to the map object Problems during project During the project the biggest problem that has faced is with Geoserver The problem was related to extensive loading times for map layers on the page The performance of the geoserver was compared with the existing geoserver on the other department in the university After many tries the problem was detected to be data itself A new set of data layers was produced and imported to geoserver and test the performance and after that it works fine Another problem we have noticed is with Java Runtime Environment JRE In the project latest version of JRE was used version JRE 7 that created problems by giving high load on the server and degrades the performance of geoserver To solve this problem JRE 6 version instead is used which works fine Finally the whole project feels like very
33. t if needed And format image png defines that the layer superimposed on the map is a png image that is generated by the geoserver OpenLayer Bounds defines the position of the layer on the world map The values will be obtained in geoserver in both meters and degrees Values can be used in maps with different coordinate system By setting the resolution of the map to auto makes it automatically adjust according to the zoom level on the map It is not necessary to define the projection of the WMS layer but if needed It is possible to specify the projection system of the WMS layer isBaseLayer property defines the layer time weather it is a baselayer or background layer on the map or overlay layer on top of baselayer By setting 0_Kr http 130 237 175 39 8080 geoserver wms land_upplift Layer name Adress of WMS layer on the Geoserver layers 0_Kr transparent true format image png Layer name on geoserver Asssign properties to the WMS layer maxExtent new OpenLayers Bounds 585000 6600000 740000 6722500 maxResolution auto Image size Image resolution projection EPSG 3006 units m isBaseLayer false visibility true WMS layer projcection Define base layer property Visibility property visibility true when the webpage open the layer will be seen on the map It can also be set to false which restricts the WMS layer to show on the map automat
34. ta Tiling Tiling is a fairly new development it is the process of dividing a large map into small pieces in the form of square tiles and send these separately from the server which improves the performance of the web map Map tiling can be done in two ways client side or server side The map can be pre tiled in the server before the map is loaded into the web page This will improve the loading time of the map but the main drawback of this is that it is a time consuming process But once the tiles are made in the server the tiles can instead directly be sent from the server There is also a possibility to tile the map at different zoom levels on the server On the client side the user selects the interested area and map client requests the tiles from the server The size of map tile increase twice in height and width for each increasing zoom level on the map When the user zooms in or out into the place of interest the server will generate the map for that particular area At zoom to maximum extent on the map the user may not recognize the map tiles but when zooming in repeatedly it is possible to see the map appear in the form of squares Figure 2 Determination of Tiles to be loaded Sch tze Web Mapping 2007 Open Geospatial Consortium The Open Geospatial Consortium OGC was formed in 1994 from the Open GRASS Foundation OGF It is a non profit organization working in collaboration with more than 480 companies by 2013 government orga
35. und color to red for h1 heading on the web pagen W3Schools JQuery Tutorial Geoserver Geoserver is a Java based server that can allow map creating and data sharing It is completely open source and work under OGC standards It can allow display sharing the well spatial data to the world through the web Geoserver comes with a WMS that can fit into other Java applications like OpenLayers and can create maps of different formats It comes with inbuilt Geotools which is an open source Java GIS toolkit that allows GIS operations on the map Geoserver can display data on the any popular modern mapping applications like Google Maps Google Earth Yahoo Maps etc even it can connect to the traditional desktop GIS tools like ESRI ArcGIS Complete instruction of the Geoserver installation is provided in the appendix of this report Geoserver Results To create the dynamic web page HTML CSS and JQuery have been used in this project Tiff files were produced for 500 year intervals from 5000BC to 1500AD using traditional desktop GIS tool ArcMap After the production of the layers they were imported to the Geoserver in order to display them on the modern map servers like Google Maps Google Earth and Open Street Map etc On the web page data were projected in two different map projection systems Swedish map projection system SWEREFF99 TM and used for world mapping WGS84 lat long system When the page load map with data projected on
36. yer group This is a very useful feature that can help to combine different layers in the geoserver Here you can create a single layer by selecting multiple layers that already exist in the geoserver The important thing to know is that you can only combine different layers that are in the same workspace It is not possible to combine layers in different workspaces Services Data presentation in geoserver can be served to the web in three different types WCS WFS and WMS Web coverage service WCS is the data type that provides available information in a specific format that can be used in the scientific modeling Web feature service WFS is a service that renders data including feature geometry and its attributes This type of data supports data query on the web This WFS service is available for vector data Finally and most common data service that are widely used is a web map service WMS which provides the data in map tiles This service is typically for raster data Tile catching As we discuss above geoserver provides raster data in the form of map tiles When the user interact with zooming or panning around the map server needs to generate the tiles In case of large raster data the server takes a long time to render image into the web page which makes the user inconvenient to reduce this rendering time it is possible to catch the map tiles and store in geoserver before the user interact with the map By doing this server does not have to
Download Pdf Manuals
Related Search