1. Open Source GIS How we use free tools to do cool things Martin Catala Donald Hayward

2. Why Open Source?

3. Error 999999

4. ● "Free Open Source Software" (FOSS) o Free ($0) o Free (-dom) ● Control ● Flexibility ● Quality (more eyes, more contributors) ● Innovation Why Open Source?

5. ● "Plays nice" with others o Open Standards mean you can keep ESRI but still get benefits from FOSS o SHP, WMS, WFS, KML, GeoJSON, etc. ● Enterprise-grade software and support o Open Source GIS tools are not just toys anymore (Boundless) Why Open Source?

6. ● It's more fun o Fewer don'ts and can'ts o If you can dream it, you can build it o The cool kids are doing it Why Open Source?

7. ● Still skeptical? ESRI isn't. o Python (ArcPy) o https://github.com/Esri Why Open Source?

8. How we use Open Source

9. ● PostGIS (a spatial database system) ● QGIS (a desktop GIS application) ● OpenStreetMap ● GeoServer (c.f. ArcServer) Our (abbreviated) Toolbox: ● Python (GDAL, Mapnik, cluster computing) ● OpenTripPlanner (Analyst Engine) ● OpenLayers, Leaflet, D3.js (Web Mapping)

10. Transit Livability Explorer

11. Made with: ● OpenLayers (web map) ● PostGIS (backend, analysis) ● QGIS (analysis, data management) ● ArcMap (analysis) Transit Livability Explorer

12. Analysis ● Multi-step, often changing hands several times (ArcGIS -> PostGIS -> QGIS -> etc.) ● Large-scale operations scripted with ArcPy, PostGIS SQL, or GDAL Python on USF Research Cluster Transit Livability Explorer

13. Click to select: ● OpenLayers translates the click into (x,y) ● A web API queries an indexed PostGIS table for features intersecting the clicked coordinates Transit Livability Explorer

14. Simplified GeoJSON Features with PostGIS: SELECT ST_AsGeoJSON( ST_Simplify( geom, 100 ) ) FROM `table`; Transit Livability Explorer

15. MPO Advisory Council Map

16. ● Project constraints: o Dynamic web map o Must work on all major browsers (even IE) o Quick update when boundaries change o No server-side processing o No cloud "add-ins" MPO Advisory Council Map

17. First Attempt: ● GeoJSON on OpenLayers/Leaflet/GMaps ● Several layers with many features and high-resolution boundaries ● Worked fine on my computer ● Client's browser crashed MPO Advisory Council Map

18. Then we tried... ● Simplifying geometries o Better, but old version of IE still choked ● Rendering static images o ArcGIS screwed up the georeferencing export MPO Advisory Council Map

19. Finally... ● Re-discovered Mapnik o Python-based mapping library o Custom-made slippy tiles o Accepts Shapefiles as input o Generates 100,000+ map tiles in a few minutes. MPO Advisory Council Map

20. ● Open Source is cheap ● Open Source is practical ● Open Source is cool Summary

21. Questions?