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Implementation of an Open-Source Internet Map Server

Implementation of an Open-Source Internet Map Server. Lowell Ballard Virginia Economic Development Partnership. Topics to be Covered. Overview of “MapServer” Various methods to implement MapServer The Implementation at VEDP The gory details Comparison to other Internet Map Servers

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Implementation of an Open-Source Internet Map Server

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  1. Implementation of an Open-Source Internet Map Server Lowell Ballard Virginia Economic Development Partnership

  2. Topics to be Covered • Overview of “MapServer” • Various methods to implement MapServer • The Implementation at VEDP • The gory details • Comparison to other Internet Map Servers • What you should consider when choosing an Internet Map Server

  3. MapServer Overview • MapServer is an OpenSource development environment for building spatially enabled Internet applications. • The MapServer was originally developed by (UMN) ForNet project in cooperation with NASA and the Minnesota DNR • Current development is funded by the TerraSIP project, a NASA sponsored project between the UMN and consortium of land management interests. • MapServer will run where most commercial systems won't or can't, on Linux/Apache platforms. • MapServer is known to compile on most UNIXes and will run under Windows NT/98/95/00.

  4. MapServer Implementation Options • MapServer can be implemented as a CGI application. • The MapServer CGI application provides a significant number of "out-of-the-box" features. • vector formats supported: ESRI shapefiles, simple embedded features, ESRI ArcSDE • raster formats supported: TIFF/GeoTIFF, GIF, PNG, ERDAS, JPEG and EPPL7 • quadtree spatial indexing for shapefiles • fully customizable, template driven output • feature selection by item/value, point, area or another feature • TrueType font support • support for tiled raster and vector data (display only) • automatic legend and scalebar building • scale dependent feature drawing and application execution • thematic map building using logical or regular expression based classes • feature labeling including label collision mediation • on-the-fly configuration via URLs • on-the-fly projection

  5. MapServer Implementation Options • MapServer system supports MapScript which allows popular scripting languages such as Perl, Python, Tk/Tcl, Guile and even Java to access the MapServer C API. • This is analogous to Active Server Pages (.asp) and ColdFusion (.cfm) in the ClosedSource world. • MapScript provides a rich environment for developing applications that integrate disparate data. • If the data have a spatial component, and you can get to it via your favorite scripting environment, you can map it. • Additionally MapScript allows you to integrate your business data in an RDBMS (e.g., Oracle, MySQL, Sybase) into your MapServer application.

  6. MapServer Implementation Options • In addition, there is now a PHP/MapScript module included in the current release. • This provides a powerful OpenSource alternative to .asp, .cfm and other server-side scripting languages. Example 1: HTML alone Hello, World! Example 2: PHP code alone <?php print "Hello, World!"; ?> Example 3: PHP embedded within HTML <?php print "Hello,"; ?> World!

  7. Implementation at the VEDP • We have used the CGI version for the past year. • Recently we added a PHP version. • Both are linked from the main page of http:gis.vedp.org

  8. The Gory Details - CGI MAP FILE ------------- Contains the basic configuration for the map service: Layers Image output directory Projections Image Size Symbology Legend properties Scale bar Property References MapServer CGI --------------------- Compiled to support Various functionality needed: SDE MapInfo support png, gif, jpg TrueType fonts Generates and returns images TEMPLATE FILE(s) ------------- Contains the code to create the map interface: HTML JavaScript Layers list Zoom buttons Tables Image, legend and Scale bar placement Submit form Calls

  9. .map File Example NAME DEMO STATUS ON SIZE 600 500 FONTSET /usr/local/apache/htdocs/vedp_maps/fonts/fonts.list SYMBOLSET symbols/symbol.sym EXTENT -400000 50000 400000 400000 UNITS FEET SHAPEPATH "data" IMAGECOLOR 255 255 255

  10. .map File Example - simple LAYER NAME counties #Layer name TYPE POLYGON DATA county #shapefile name STATUS ON CLASSITEM tile_name #for queries use this LABELITEM "name“ #label using this item SYMBOLSCALE 1500000 #Start scaling at this resolution LABELMAXSCALE 600000 #Start labeling at this scale HEADER county_header.html #Header template for queries CLASS #Start of a map class NAME "Counties“ #Name for Legend EXPRESSION /./ #could be pop90 > 10000 e.g. OUTLINECOLOR 128 128 128 COLOR 245 240 219 TEMPLATE county.html #used to build query output LABEL #Builds the label SIZE 8 MINSIZE 2 MAXSIZE 8 COLOR 0 0 0 BACKGROUNDCOLOR 255 255 204 BACKGROUNDSHADOWSIZE 4 4 BACKGROUNDSHADOWCOLOR 0 0 0 TYPE TRUETYPE FONT tahoma ANTIALIAS BUFFER 1 END END END

  11. .map File Example – multiple classes CLASSITEM "ROAD_TYPE" CLASS EXPRESSION "1" COLOR 0 0 0 SYMBOL 'symbols/images/interstate.png' LABEL SIZE 2 MINFEATURESIZE 40 MINDISTANCE 150 POSITION CC SIZE TINY COLOR 255 255 255 END END CLASS EXPRESSION "2" COLOR 0 0 0 # dummy color SYMBOL 'symbols/images/ushwy.png' LABEL MINFEATURESIZE 50 MINDISTANCE 150 POSITION CC SIZE TINY COLOR 0 0 0 END END

  12. .map File Example - Raster LAYER NAME spot2001 TYPE RASTER STATUS OFF TILEINDEX spot_2001/spotindex TILEITEM "LOCATION" MAXSCALE 25000 MINSCALE 3000 OFFSITE 0 END

  13. The Gory Details • The hardest part is the compilation process. • Because it’s open source it pulls from many different projects with many different developers. • If you need support for something (e.g., TrueType fonts) it has to be compiled in (e.g., FreeType). • This can be a pain. • However, installation of most IMServers is a pain.

  14. Subset of Compilation Options • --with-gd[=[static,]DIR] Specify which version of GD to use (DIR is GD's • install dir). • --with-freetype=DIR Specify where FreeType is installed (DIR is path to • FreeType 2.x freetype-config program or FreeType 1.x/2.x install dir). • --with-zlib=DIR Specify where zlib is installed (DIR is path to • zlib install dir). • --with-png=DIR Specify where PNG is installed (DIR is path to • PNG install dir). • --without-tiff Disable TIFF support. • --with-tiff[=DIR] Include TIFF support (DIR is LibTIFF's install dir). • --without-eppl Disable EPPL7 support. • --with-eppl Include EPPL7 support. • --with-proj[=DIR] Include PROJ.4 support (DIR is PROJ.4's install dir). • --with-sde[=DIR] Include ESRI SDE support (DIR is SDE's install dir). • --with-sde-version[=VERSION NUMBER] Set ESRI SDE verion number (Default is 80). • --with-mpatrol[=DIR] Include MPATROL support (DIR is MPATROL's install dir). • --with-ogr[=DIR] Include OGR support (DIR is OGR's install dir). • --with-gdal[=DIR] Include GDAL support (DIR is path to gdal-config • --with-postgis[=ARG] Include PostGIS Support (ARG=yes/path to pg_config) • --without-wms Disable OGC WMS Compatibility (enabled by default). • --without-wmsclient Disable OGC WMS Client Connections (enabled by default).

  15. Comparison--Speed • MapServer is faster • I compared MapServer running on a PII Desktop with 128 MB RAM to another IMS running on a PIII 512 MB RAM Server. • CPU usage for MapServer was about 20% per map rendered and took about 1 second. • CPU on other IMS took about 8-10 seconds and 100% CPU utilization.

  16. Comparison--Support To: mapserver-users@lists.gis.umn.edu Subject: [mapserver-users] mapraster.c compile error--- From: "Ballard,Lowell" <LBallard@YesVirginia.org> Date: Mon, 20 Aug 2001 10:45:56 -0400 I've tried compiling nightly with several options and I always get the same parse errors.----------------------------------------- gcc -c -O2 -Wall -DIGNORE_MISSING_DATA -DUSE_EPPL -DUSE_TIFF -DUSE_JPEG -DUSE_GD_GIF -DUSE_GD_SWAP_XY -DUSE_SDE -I/home/baldur/mapserver/./gd-1.2/ -I/home/baldur/mapserver/../sdeexe81//include mapraster.c -o mapraster.o =========================================== To: "Ballard,Lowell" <LBallard@YesVirginia.org> Subject: Re: [mapserver-users] mapraster.c compile error--- From: Daniel Morissette <morissette@dmsolutions.ca> Date: Mon, 20 Aug 2001 11:04:40 -0400 CC: mapserver-users@lists.gis.umn.edu References: <509989F9E1D38D47ADA73ED9CF5BF32A16CEDD@communications> > I've tried compiling nightly with several options and I always get the > same parse errors. > mapraster.c: In function `msDrawRasterLayer': > mapraster.c:1698: parse error before `{' It's a typo related to a change I made last week. It was a missing bracket inside an #ifdef'd case that was never compiled in my case. I've committed a fix, so please do a CVS update and try again.

  17. Comparison--Support • The ListServ is very active and very responsive • Messages are archived and searchable • I usually get a response to my problem in in hour or less

  18. Comparison—Cost • MapServer is completely free. • It is free from cost • You are free to modify the source code • As people make changes or develop enhancements they are committed to the development tree. • This is how the product grows so rapidly

  19. Recent Developments • Major advancements in Web Mapping Services. • Ability to handle .axl requests from ArcGIS

  20. What to consider • Your “Need for Speed” • Your in-house abilities • Database connectivity • GIS data formats • Your budget

  21. Resources • http://gis.vedp.org (“about this site” link) • DM Solutions (PHP MapScript) (http://www.dmsolutions.on.ca/) • ApacheToolbox (http://www.apachetoolbox.com) • Google (http://www.google.com) which runs on a Linux cluster .

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