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Web gis implementation notes
- 1. Notes from a WebGIS implementation (for non-programmers and desktop GIS users) Paolo Verri <paolo.verri@gmail.com>
- 2. From Desktop GIS to WebGIS: architecture
- 3. Desktop GIS Architecture Local GIS Program Local Data (everything is near you, on your PC)
- 4. Web GIS Architecture Browser Web Local GIS GIS Client Client Network Remote Data MapServer (GIS Database)
- 5. Build a WebGIS: 4 main activities
- 6. 1 WebGIS architecture setup ! IT skills
- 7. 2 data production & manipulation ! Geo & SQL skills, data structure design is critical
- 8. 3 web map configuration& styling !! Geo skills, styling can be time- consuming
- 9. 4 map-user interaction !!! IT & Geo skills, lots of javascript programming, time-consuming
- 10. From Geodatabases to PostGIS (Vector data)
- 11. Shapefiles, Geodatabase DBF files 1
- 12. Shapefiles, SQL files DBF files 2 shp2pgsql myshapefile.shp myschema.mytable > mytable.sql ! SRID Input encoding Identifier’s case
- 13. SQL files PostGIS 3 pgsql mytable.sql ! Database configuration Output encoding Dataset size
- 14. From PostGIS to Web Maps (with MapServer)
- 15. Web Map ? Image, representing geographic information, with an internet address (URL), displayed in a web browser
- 16. Image Address (URL) Map Web Browser
- 17. MapServer ? Receives browser requests, queries PostGIS database, produces images, sends them back to browser
- 18. Publishing Web Maps = Tell MapServer how to build images out of geographic data when requested by web browsers.
- 19. How to tellMapServer: configuration example. Web Map Name Geographic Extent and Geometry Type PostGIS connection Styling
- 20. From WebMaps to Web GIS (interacting with maps)
- 21. geographic data storage, calculations and maps production happen far far away. map interaction happens near you (yes, in your browser, thanks to javascript)
- 22. Basic Web MapInteraction (read only) = Pan Zoom Layers switch = Openlayers javascript library
- 23. Complex Web MapInteraction (read, write) = Query features infos Select features Calculations (distance, area...) Input data forms = GeoExt javascript library
- 24. Tools of thetrade
- 25. Store and organizethe data Postgres (SQL database) + PostGIS (geo extensions and utilities) + pgAdmin (GUI, database front end) (but there’s a command line too) http://postgis.refractions.net/
- 26. Manipulate the data GDAL (raster geospatial data formats) + OGR (vector geospatial data formats) (ESRI shapefiles!) + PROJ.4 (cartographic projections) Packages found at: http://www.maptools.org/
- 27. Generate and PublishMaps Mapserver (generate maps and more...) + PHP/Mapscript (programming language, for dynamic map generation) (it happens server side!) + Web Server (send maps to the browser) (and HTML pages too) Packages found at: http://www.maptools.org/
- 28. Manage User Interaction javascript + Openlayers (maps in html pages) + ExtJS (javascript library, complex GUIs) http://www.geoext.org/