Web-Based Open Source GIS: Decision Support Tools Explaining the Software Stack Presented by Aaron Racicot – GIS Programmer [email protected] April 19th,

Web-Based Open Source GIS:

Decision Support Tools Explaining the Software Stack

Presented by Aaron Racicot – GIS Programmer

[email protected] 19th, 2006

A Citizen of Salmon Nation

Outline

Introduction – Personal and Ecotrust Software Stack – Desktop, Web, DST Workflow & Dataflow Raster Tools – Mapserver->GRASS Vector Tools – Mapserver->PostGIS Glue – AJAX, OGR/GDAL,… Installation and tool selection Where is it all going?

Who am I…B.S. Computer

Science

Split Personality

M.S. Environmental Science

Open Source User/Developer

GIS Programmer

Ecotrust - Salmon Nation

Software Stacks… Desktop

Generic Stack FOSS4G Stack Grouping

Application QGis, Grass, OSSIM, JUMP, UDig

User Interface

Application Dev. Environment

Eclipse, QT, OpenGL

High Level Utilities GeoTools, PostGIS Data Serving

High Level Scripting Languages

PHP, PERL, Python

Low Level Utilities Shplib, GEOS, OGR/GDAL, PostGIS, R-Statistics, GMT

Data Processing

Low Level Languages

C, C++, Java, Fortran System Software

Operating System

Linux, Darwin, Cygwin

Hardware Drivers

32-64 bit processor drivers

Desktop Software Stack

Software Stacks... Server

Server Software StackGeneric Stack FOSS4G Stack Grouping

Client Side Browser Firefox, Safari, Netscape User Interface

Client Side Scripting

Java Script, Java Applets

~~~~~~~~~~~WEB~~~~~~~~~~~

Server Side Application

Chameleon, Cartoweb3, Custom Data Serving

High Level Utilities Mapserver, PCO, Grass

Low Level Utilities Shplib, GEOS, OGR/GDAL, PostGIS, R-Statistics, GMT

Data Processing


PHP, PERL, Python

Low Level Languages


Operating System/Drivers

Linux, Darwin, Cygwin

Hardware Drivers 32-64 bit processor drivers

Software Stack... DSTs (Ecotrust)

DST Software StackGeneric Stack FOSS4G Stack Grouping

Client Side Browser Firefox, Safari, Netscape User Interface

Client Side Scripting

Chameleon/Custom

~~~~~~~~~~~WEB~~~~~~~~~~~

Server Side Application

Chameleon/Custom Data Serving

High Level Utilities Mapserver, GRASS, PostGIS

Low Level Utilities Shplib, GEOS, R-Statistics, GMT, OGR/GDAL

Data Processing


PHP, PERL

Low Level Languages


Operating System/Drivers

Linux (Fedora)

Hardware Drivers 32 bit processor drivers

Work Flow – What OSGIS is good at

Web User Request

Web User Response

StaticData Storage

WebService

sData Gathering

Data Formatting

Data Processing

Map Formatting

Map Production

The Problem Is The Arrows! Connecting a web request to server side GIS analysis is tricky

Real-Time Web Decision Support Tools

Data Flow... DSTs (Ecotrust)

General PHP Mapscript

dl('php_mapscript.so');dl('php_proj.so');

$oMap = ms_newMapObj(MAPFILE);

// Set the data directory$oMap->set("shapepath", $session_tmp_dir."data");

// Now we need to set the save path and image URL to a session based directory...

$oWeb = $oMap->web;$oWeb->set("imagepath",$session_tmp_dir);$oWeb->set("imageurl",$session_tmp_dir);

// Explode the x,y extents$box_coords = explode(" ", $http_form_vars["imgbox"]);$point_coords = explode(" ", $http_form_vars["imgxy"]);

PHP Mapscript - Zooming

// Check if the box is to small and we should just use the x,yif ((abs($box_coords[0] - $box_coords[2]) < 5) && (abs($box_coords[1] - $box_coords[3]) < 5)){ zoomPoint( $oMap, ZOOMOUT_FACTOR, $point_coords[0],$point_coords[1] );} else{ zoomRectangle( $oMap, $box_coords[0], $box_coords[1], $box_coords[2], $box_coords[3] );}

PHP Mapscript - Rendering

$img = $oMap->draw();$url = $img->saveWebImage();

$oMap->scalebar->set("transparent", MS_TRUE);$img_scale = $oMap->drawScaleBar();$url_scale = $img_scale->saveWebImage();

$oMap->legend->set( "template", APP_PATH."legend_template.html" );$params = array();$html_legend = $oMap->processLegendTemplate($params);

$img_ref = $oMap->drawReferenceMap();$url_ref = $img_ref->saveWebImage();

$oMap->save($session_tmp_dir."map_tmp.map");

PHP Mapscript - Integration

<appletcodebase="/java/jBox"archive="jBox.jar"code="jBox.class"width="800"height="600"name="jBox"MAYSCRIPT><param name="image" value="<?php echo HOST_URL.$url?>"><param name="verbose" value="true"></applet>

 <img src="<?php echo HOST_URL.$url_ref?>" ALT="Ref"> <table><?php echo $html_legend; ?></table>

Raster based DSTSiuslaw Watershed Restoration Initiative

Data Gathering

Data Formatting

Data Processing

PHP Mapscript

GRASS

Raster based DST

$string = “host db_str usr_str”;$connection = pg_connect($string);if (!$connection){ pg_close($connection); echo "Error:Cannot connect to database ";} else { echo "Connected to the SCA database \n";}

$res_pg_exec = pg_exec($connection,$exec_str);

PostgreSQL Type Interface for GRASS GIS

Raster based DST – GRASS Class

class Grass_GIS { var $data_dir; // Where the GRASS data

dir is var $rc_dir; // Where the GRASS rc dir is var $bin_dir; // Where the GRASS bin dir

is var $location; var $mapset; function Grass_GIS($data_dir,

$rc_dir, $bin_dir, $location, $mapset){

$this->data_dir = $data_dir; $this->rc_dir = $rc_dir; $this->bin_dir = $bin_dir; $this->location = $location; $this->mapset = $mapset; } function

Grass_GIS_copy($grass_gis){ $this->data_dir = $grass_gis-

>data_dir; $this->rc_dir = $grass_gis->rc_dir; $this->bin_dir = $grass_gis->bin_dir; $this->location = $grass_gis-

>location; $this->mapset = $grass_gis->mapset; } function set_location($location) {$this->location = $location;} function set_mapset($mapset) {$this->mapset = $mapset;} function set_data_dir($data_dir) {$this->data_dir = $data_dir;} function set_rc_dir($rc_dir) {$this->rc_dir = $rc_dir;} function set_bin_dir($bin_dir) {$this->bin_dir = $bin_dir;}

function run_command($cmd){ $std_output = ""; $grass_exec = ""; // Check that all the required info is available.. if ($this->data_dir != NULL && $this->rc_dir != NULL &&

$this->bin_dir != NULL && $this->location != NULL &&$this->mapset != NULL){// Here we will write out the script to run...$fp_data = fopen($this->data_dir."/grass_run.sh","w");// write out text headerfwrite($fp_data,"export GISBASE=".$this->bin_dir." \n");fwrite($fp_data,"export GISDBASE=".$this->data_dir." \n");fwrite($fp_data,"export GISRC=".$this->rc_dir."/.grassrc6 \n");fwrite($fp_data,"export ETC=".$this->bin_dir."/etc \n");fwrite($fp_data,"export PATH=".$this->bin_dir."/bin:".$this->bin_dir."/scripts:".$this->bin_dir. "/garden/bin:\$PATH:/usr/bin:/usr/local/bin/ \n");fwrite($fp_data,"export LOCATION_NAME=".$this->location." \n");fwrite($fp_data,"export MAPSET=".$this->mapset." \n");fwrite($fp_data,"export LOCATION=".$this->data_dir."/".$this->location."/".$mapset." \n");fwrite($fp_data,"\n");fwrite($fp_data,$cmd."\n");fflush($fp_data);fclose($fp_data);$fp_data = fopen($this->rc_dir."/.grassrc6","w");fwrite($fp_data,"GISDBASE: ".$this->data_dir."\n");fwrite($fp_data,"LOCATION_NAME: ".$this->location."\n");fwrite($fp_data,"MAPSET: ".$this->mapset."\n");fwrite($fp_data,"PAINTER: ppm\n");fwrite($fp_data,"MAPLP: stuff.ppm\n");fflush($fp_data);fclose($fp_data);$grass_exec = sprintf("chmod u+x ".$this->data_dir."/grass_run.sh");exec($grass_exec,$std_output,$std_error);

$grass_exec = sprintf($this->data_dir."/grass_run.sh");exec($grass_exec,$std_output,$std_error);

}

Raster based DST – PHP GRASSdefine("GRASSDATA_DIR", "/var/www/html/apps/siuslaw_target/data/GRASSDATA/");$location_name = "OR_siuslaw“;$mapset_name = "land_targets“;$session_grass_dir = $session_tmp_dir."/GRASSDATA";

// Make a Dir to work inecho " Make a directory to work in inside this session ";$dir_exec = sprintf("mkdir ".$session_grass_dir);exec($dir_exec,$arr,$err1); $dir_exec = sprintf("mkdir ".$session_grass_dir."/rc");exec($dir_exec,$arr,$err1); $template_path = GRASSDATA_DIR."siuslaw_epa_template";echo " Copying over new GRASS GIS template ";$dir_exec = sprintf("cp -R ".$template_path." ".$session_grass_dir."/".$location_name);exec($dir_exec,$arr,$err1); // Make a MAPSETecho " Setting up the siuslaw specific area ";$dir_exec = sprintf("mkdir ".$ session_grass_dir."/".$location_name."/".$mapset_name);exec($dir_exec,$arr,$err1); // Copy over the projection info from the PERMANENT areaecho " Setting projections ";$dir_exec = sprintf("cp ".$template_path."/PERMANENT/PROJ* ".$ session_grass_dir."/".

$location_name."/".$mapset_name."/");exec($dir_exec,$arr,$err1); $grass_session = new Grass_GIS($session_grass_dir, $session_grass_dir."/rc", "/usr/local/grass-6.0.0", $location_name,

$mapset_name);$grass_session->run_command("g.list type=rast");

Raster based DST – AML<->GRASS

$arr = $grass_session->run_command("g.region rast=owng_grass@PERMANENT"); echo "Starting to process the Siuslaw data \n";//AML step//AH2 = (ah_idx + 1) * 10 echo " Creating ah2_idx_grass... anchor habitat priorities \n"; $arr = $grass_session->run_command("r.mapcalc ah2_idx_grass = $\(ah_idx_grass@PERMANENT+1$*10\)");//AML step//own_idx = con(owng eq 31, 40,con(owng eq 83,30,con(owng eq 95,10,20))) echo " Creating own_idx_grass... ownership priorities \n"; $arr = $grass_session->run_command("r.mapcalc own_idx_grass = if$owng_grass@PERMANENT==31,40,". "if\(owng_grass@PERMANENT==83,30,if\(owng_grass@PERMANENT==95,10,20$\)\)");//AML step//reclass tpa (use slice) and setnull trees younger than 15 years//veg_idx = setnull(age_g lt 15, slice(tpa_g,eqarea,40)) echo " Reclasification of tpa_g... to 0-40 \n"; $arr = $grass_session->run_command("r.rescale.eq input=tpa_g_grass@PERMANENT ". "output=tpa_rescale to=0,40"); echo " Creating the veg_idx... trees over ".$tpa_age." years of age \n"; $arr = $grass_session->run_command("r.mapcalc veg_idx_grass = ". "if$age_g_grass@PERMANENT\>=".$tpa_age.",tpa_rescale,null\($\)");//AML step//FING = setnull(rip_stab eq 0, (ah2 + veg_idx + own_idx + ..\infra\rd_d_inv)) echo " Creating FING... the sum of ah2_idx_grass+own_idx_grass+veg_idx_grass+rd_d_inv_grass \n"; $arr = $grass_session->run_command("r.mapcalc fing_grass = ". "if$rip_stab_grass@PERMANENT==0,null\($,". "$ah2_idx_grass+own_idx_grass+veg_idx_grass+rd_d_inv_grass@PERMANENT$\)")\;

Raster Example – TREESystemMapserver on the front end… GRASS on the back end…

Web-based Query

Raster based DST - Mapfile LAYER NAME "Fishery Rev" STATUS DEFAULT DATA

"./GRASSDATA/CAL_ocean2/FISHERY/cellhd/fishery_rast_rev_zone_8bit" TYPE RASTER PROJECTION "proj=aea" "datum=NAD27" "ellps=clrk66" "lat_1=34" "lat_2=40.5" "lat_0=0" "lon_0=-120" "x_0=0" "y_0=-4000000" "units=m" END END

Vector based DST

Mapserver

PHP -> PHPMapscript -> PostGIS

PostGIS

Vector based DST - Database// Now connect to the db$host_str = "host=localhost";$db_str = "dbname=shelf_closure_db";$usr_str = "user=web_user";$string = $host_str." ".$db_str." ".$usr_str;$connection = pg_connect($string);if (!$connection){ pg_close($connection); echo "Error: Cannot connect to the database \n";} else { echo "Connected to the SCA database \n";}

// Create a dynamic VIEW in PostGISecho "* Create postgresql VIEW * \n";$exec_str = sprintf("CREATE VIEW ". $previous_session_name."_".$previous_session_id." AS ". "SELECT bk.the_geom, sum(tr.total_lbs*tb.percent) as total_lbs ". "FROM tow%02d_3kblk_intersect as tb, trawl%02d". " as tr, cablk3km as bk, port as pt ". "where tb.blk_gid=bk.gid ".$species_sql." ".$port_sql." ".$gear_sql. " and tb.tow%02d_id=tr.tow_id2 ". "GROUP BY bk.the_geom HAVING count(tr.tow_id2)>2", $start_year_short,$start_year_short,$start_year_short);$result_pg_exec = pg_exec($connection, $exec_str);if (!$result_pg_exec) { printf("%s \n", pg_errormessage());}

Vector based DST – Dump results// Execute the pgsql2shp to create the outputecho "* Execute pgsql2shp create the shapefile in session directory * ";$dir_exec = sprintf("/usr/local/pgsql/bin/pgsql2shp -u web_user -f ". $session_tmp_dir."data/target_areas/test_output.shp shelf_closure_db ". "\"SELECT * from ".$previous_session_name."_".$previous_session_id."\"");exec($dir_exec,$arr,$err1); for ($ii=0;$ii<count($arr);$ii++){ echo $arr[$ii]." \n";} // Drop the dynamic table echo "* DROP the postgresql VIEW * \n";$result_pg_exec = pg_exec($connection, "DROP VIEW ". $previous_session_name."_".$previous_session_id);if (!$result_pg_exec) { printf("%s \n", pg_errormessage());}

Vector Example - OCEANSystem

Rockfish – SFA - 2001 Rockfish – SFA - 2003

Shelf Closure mid-2002

AJAX - Prototypefunction gotVariable(varName, varVal, showWait){ // URL to send the AJAX request to var url = 'http://boris.ecotrust.org/gulf_project/core/SCA_Model/contents.php'; // Push the variable onto the array of parms var newVars = new Array(varName,varVal); varStack.push(newVars); // Build the params for the URL request var pars = ""; for (var i=0; i<varStack.length;i++) { if (i == 0) {pars = pars + varStack[i][0] + '=' + varStack[i][1];} else {pars = pars + '&' + varStack[i][0] + '=' + varStack[i][1];} } // Debug text var boldText = document.createElement('b'); var actionText = document.createTextNode(varName + ' :: '); var action2Text = document.createTextNode(varVal); boldText.appendChild(actionText); var breakText = document.createElement('br'); document.getElementById('placeholder_current').appendChild(boldText); document.getElementById('placeholder_current').appendChild(action2Text); document.getElementById('placeholder_current').appendChild(breakText); // Make the AJAX request var myAjax; myAjax = new Ajax.Updater('placeholder_select', url, {method: 'get', parameters: pars,

onLoading: showWaitImage, onComplete: removeWaitImage}); currentStep++;}

AJAX - Prototype$action_array = array("0" => "init_action", "Revenue by Species" => "process_rev_by_species", "Revenue by Gear Type" => "process_rev_by_gear", "Revenue Total" => "process_rev_by_total", "Num Vessel Landings" => "process_num_vessel_landings", "Distinct Vesseles" => "process_distinct_vessels", "Average Rev Per Vessel" => "process_average_rev_per_vessel", "Distinct Fishermen" => "process_distinct_fishermen", "Distinct Species" => "process_distinct_species");

if (isset($http_form_vars["Action"])){$function_ret = $action_array[$http_form_vars["Action"]]($connection, $http_form_vars);}else{ // deal with the initial request echo "<div id=\"placeholder_select\">\n"; $function_ret = $action_array[0]($connection, $http_form_vars); echo "</div>\n"; echo "<div id=\"placeholder_current\">\n"; echo "</div>\n";}

AJAX - Prototypefwrite($fp_data, "palette(rainbow(".count($y_string)."))\n");fwrite($fp_data, "bitmap(\"species_revenue_".$rand_number.".png\", type =\"png256\", height =

2, width = 4, res = 300)\n");fwrite($fp_data,"plot(x,seq(min(".$y_s."),max(".$y_s.")*1.4,length=length(x)),type=\"n\",xl

b=\"Year\",ylab=\"Revenue\")\n");for ($i=1; $i<=count($y_string); $i++) { fwrite($fp_data,"lines(x,y_".$i.",col=".$i.")\n"); if ($i==1) { $fill_col = $i; } else { $fill_col = $fill_col.",".$i; } }fwrite($fp_data,"legend(x=min(x),y=max(".$y_s.")*1.4,c(".$species_s."),fill=c(".$fill_col."),

bg=\"white\", ncol=4)\n");fwrite($fp_data,"title(\"Revenue plot for Species Groups at Port Group ".$port."\")\n");fwrite($fp_data,"dev.off()\n");fflush($fp_data);fclose($fp_data);$dir_exec = "/usr/local/bin/R CMD BATCH species_revenue_".$rand_number.".R";exec($dir_exec,$arr,$err1);echo "<img height=\"400\" width=\"800\" src=\"./SCA_Model/pictures/species_revenue_".

$rand_number.".png\"> \n";

GDAL/OGR – Shapefile validityfunction check_valid_shapefile($shape_file_name){ //echo "Checking that shapefile ".$shape_file_name." is valid... \n"; $valid = TRUE;

$duplicate = FALSE; $importance_present = FALSE;

$name_temp = array(); // Here we need to check for the validity of the shapefile $dir_exec = sprintf("/usr/local/bin/ogrinfo -al ".$shape_file_name); exec($dir_exec,$arr1,$err1); for ($ii=count($arr1)-1; $ii>=0; $ii--) { if ((substr_count($arr1[$ii],": Integer") > 0) || (substr_count($arr1[$ii],": Real") > 0) || (substr_count($arr1[$ii],": String") > 0)) { // Push them all onto an array $string_to_chop = strstr($arr1[$ii],":"); $key_word = str_replace($string_to_chop,"",$arr1[$ii]); array_push($name_temp,$key_word); //echo $key_word." \n"; } }

GDAL/OGR – Cont.for ($ii=0; $ii < count($name_temp); $ii++) { for ($iii=$ii+1; $iii < count($name_temp); $iii++) { if ($name_temp[$iii] == $name_temp[$ii]) { // we have a duplicate $duplicate = TRUE; $duplicate_name = $name_temp[$ii]; } if ($name_temp[$ii] == "IMPORTANCE") { $importance_present = TRUE; } } }

if ($duplicate == TRUE) { echo " ERROR: We found a shapefile with duplicate columns named ". $duplicate_name." \n"; $valid = FALSE; } if ($importance_present == FALSE) { echo " ERROR: We found a shapefile named ".$shape_file_name. " without an IMPORTANCE column \n"; $valid = FALSE; }

return $valid;}

10 Step Tool Install1) First install Fedora Core4 with

updates2) Proj.4tar -xzvf proj-4.4.9.tar.gzcd proj-4.4.9cd nad/cp ../../proj-nad27-1.2.tar.gz .tar -xzvf proj-nad27-1.2.tar.gzcd .../configuremakemake install

3) GDALInstalled the ECW SDK (do a config, make

and install)Installed the MrSid SDK (moved to

/usr/local)wget http://gdal.org/dl/gdal-1.3.1.tar.gztar -xzvf gdal-1.3.1.tar.gzcd gdal-1.3.1./configure --with-ecw --with

mrsid=/usr/local/GeoExpressSDK/make ogr-allmake installwhich gdalinfo4) GEOSwget http://geos.refractions.net/geos-

2.2.1.tar.bz2tar -xjvf geos-2.2.1.tar.bz2cd geos-2.2.1./configuremakemake install

10 Step Tool Install5) POSTGRESQL

tar -xzvf postgresql-8.1.2.tar.gz

cd postgresql-8.1.2

NOTE the LDFLAGS here... this is to support GEOS for postGIS

LDFLAGS=-lstdc++ ./configure --with-perl --prefix=/usr/local/pgsql_8_1_2

gmake

gmake install

Add the shared library path to /etc/ld.so.conf :

/usr/local/pgsql_8_1_2/lib

Run /sbin/ldconfig

Finally add the following to the profile file to make paths available:

PATH=$PATH:/usr/local/pgsql/bin

MANPATH=$MANPATH:/usr/local/pgsql/man

export MANPATH

Add the postgis user

useradd postgis

passwd

[postgis@localhost pgsql]$ postmaster -D ./data/ > ./data/logfile.txt 2>&1 &

6) POSTGISJust make sure that the Postgresql is

configured with the LDFLAGS variable set and that the GEOS software is downloaded and installed from Refractions.

./configure --with-proj --with-geos --with-pgsql

makemake installNow we can create the database:createdb -O aaronr test_dbcreatelang -U aaronr plpgsql test_dbpsql -f

/usr/local/pgsql_8_1_2/share/postgresql/

contrib/lwpostgis.sql -d test_db

10 Step Tool Install7) PHP./configure --prefix=/usr/local/php4 --program-

suffix=4 --enable-force-cgi-redirect --with-config-file-path=/etc/httpd/ --with-gd=/usr/local/ --with-jpeg --with-png --with-tiff --with-zlib --with-freetype-dir --without-ttf --with-mysql --with-regex=system --enable-dbase --enable-dbx --enable-versioning --with-pgsql=/usr/local/pgsql_8_1_2/

makemake installstrip sapi/cgi/phpcp sapi/cgi/php /var/www/cgi-bin/php4cp php.ini-dist /etc/httpd/php.iniMade the following mod to /etc/httpd/php.ini:; Directory in which the loadable extensions

reside.;extension_dir = "./"extension_dir = "/etc/httpd/php_mods"mkdir /etc/httpd/php_modsAdded the following to /etc/httpd/conf/httpd.conf## For PHP scripts as CGI-BINAddType application/x-httpd-php-

cgi .php4 .phtmlAction application/x-httpd-php-cgi /cgi-bin/php4Now re-start the server:/etc/rc.d/init.d/httpd restartStopping httpd:

[ OK ]Starting httpd: [ OK ]

8) MAPSERVER./configure --with-jpeg --with-gd --with-

freetype --with-zlib --with-png --with-pdf --without-tiff --with-proj --with-threads --with-ogr --with-gdal --with-postgis --with-wfs --with-wmsclient --with-wfsclient --enable-debug --with-php=/src/php/php-4.4.2

makecp legend mapserv scalebar /var/www/cgi-

bin/cp mapscript/php3/php_mapscript.so

/etc/httpd/php_mods/9) GRASSCFLAGS="-g -Wall" ./configure --with-

gdal=/usr/local/bin/gdal-config --with-postgres-includes=/usr/local/pgsql/include/ --with-postgres-libs=/usr/local/pgsql/lib/

makemake install10) R-Statisticstar -xzvf R-2.1.1.tar.gzcd R-2.1.1./configuremakemake install

Where to go for more infoOSGIS

Maptools - http://www.maptools.org FreeGIS - http://freegis.org/ Open Source GIS - http://opensourcegis.org/

Standards OGC - http://www.opengeospatial.org/

Desktop GRASS - http://grass.itc.it/ QGIS - http://qgis.org/ UDIG - http://udig.refractions.net/confluence/display/UDIG/Home JUMP – http://jump-project.org/ OpenEV - http://openev.sourceforge.net/

Server/Web Mapserver - http://mapserver.gis.umn.edu/ GRASS - http://grass.itc.it/ PostGIS - http://postgis.refractions.net/

Tools Remote Sensing - http://remotesensing.org/tiki-index.php GDAL/OGR - http://gdal.maptools.org/index.html PROJ.4 - http://proj.maptools.org/ R-Statistics - http://www.r-project.org/ GMT - http://gmt.soest.hawaii.edu/

The End

Tool Screen Shots Follow

Backup - GRASS

Backup – R-Statistics

Backup – PostGIS

Geometry

WKT Geometry

Backup - QGIS

Documents

Web-Based Open Source GIS: Decision Support Tools Explaining the Software Stack Presented by Aaron Racicot – GIS Programmer [email protected] April 19th,