Open Source GIS

Discussion and ExamplesCSIG 06 – 16Aug2006

Chris Condit (condit@sdsc.edu)

Overview Slide

• Why bother with open source GIS?

• Discuss some tools

• Hands on– OGR– MapServer– OpenEV

What’s the point?

• Licensing costs

• Smaller footprint

• Less resource intensive

• Active and responsive community

• Somewhat more accessible

• Embracing OGC standards

• Not for everyone

Useful, free tools

• FWTools (http://fwtools.maptools.org)– PROJ.4, OpenEV, gdal/ogr

• MapServer (http://mapserver.gis.umn.edu)

• MS4W (http://www.maptools.org/ms4w)

• PostGIS (http://www.postgis.org)

• Google Earth (http://earth.google.com)

Google Earth hubbub

“…not to show geographical information but to show the world information geographically.”

Michael Jones

Google Earth considerationsYes No

Visualization

Coolness

Imagery

Free (personal use)

Analysis

Editing

Extensible

Open source

Slow networks

GML vs KML

• Similar, but different

KML is a dirty mix of style and formatting. Be careful.

Exercise

• Using OGR to create KML

• http://aqua.sdsc.edu/csig/KMLTutorial.html

MapServer

• Implements many OGC standards– WMS, WFS, WCS– Production and consumption

• Online GIS considerations

• MapScript (iobis)

• MapServer in tandem with applications

MapServer Exercise

• http://aqua.sdsc.edu/csig/mapdata.zip

• C:\tools\Apache2\htdocs\mapdata

• “Quickly” publishing GIS data online

• EXPRESSION ([MinDO2] < .5)• EXTENT -10000000 -10000000 10000000 10000000 • PROJECTION "proj=laea" "lat_0=-90" END

Grabbing PostGIS data

LAYER

CONNECTIONTYPE OGR

PROJECTION

"init=epsg:4326“

END

NAME "eezs“

CONNECTION "PG:host=aqua.sdsc.edu user=csig password=csig dbname=csig“

DATA "continents“

STATUS DEFAULT

TYPE POLYGON

CLASS

OUTLINECOLOR 0 255 0

SIZE 3

END

END

Application Server

Geospatial Mediator

iOBIS Overview (Custom MapServer App)

UMN MapServer

PostGIS

Oracle Spatial

MySQL

ESRI Formats

OGC Formats

Client Layer Application Layer Data Layer

Google Maps Client

Statistical Package

(R, MATLAB, etc)

SOA Consumer

Registration Tool

GIS Translator

Ontological Knowledge Base

OpenEV Demo

• Use the same data to create a static map in OpenEV.

Grand Conclusions

• Questions

• Comments

• Post talk observations:– Quantum GIS will render PostGIS vector

layers in an ArcMap like interface.– GRASS is also an excellent GIS tool.