1. Literate Programming and the Process of GIS Steve Signell, Instructor (signes@rpi.edu) Robert Poirier, TA (poirir@rpi.edu) School of Science Rensselaer Polytechnic Institute Monday, March 17, 2014 GIS in the Sciences ERTH 4750 (38031)

2. Literate Programming

3. The process of GIS What is the task? What data do I need What analyses do I need to perform. How is the data to be presented (Maps/Reports/Web applications…) 3

4. The process of GIS One example in action…

5. The process of GIS

6. One question that immediately comes to mind with this dataset is "just how many Ecocodes, Domains, Divisions, Provinces, and Sections are present in this map?" Fortunately, we can answer this with a simple SQL query.

7. The process of GIS Here is SQL that gives a table of names of the domains, along with area in km

8. The process of GIS Here is SQL that gives you a map of the domains

9. The process of GIS Here is SQL that gives a table of names of the divisions, along with area in km

10. The process of GIS Here is SQL that gives you a map of the divisions

11. The process of GIS Example, continued…

12. Projects & Grading: Review Short written assignments & quizzes (25%) Participation in lab, lecture & group project (25%) Individual project (50%) Vector and raster data Written & Oral Reports Must have dynamic web map component

13. Group Projects Several layers: vector and/or raster 3-4 data analysis components. Basic web map with layers & layer selector. Various assignments along the way

14. Individual Projects Most proposals are very ambitious– this is good! Doing the following will get you 75%: Several vector & at least one raster component (or vice versa) 3-4 data analysis components. Written report with static (print) maps. This will be in the style of literate programming. Basic web map with layers & layer selector. Oral report (~7 minutes, last day of class) Remaining 25%-- excel in one or more areas: Data Analysis Written Report Static Maps Web Map Oral report

15. Individual Projects

22. Homework 22 Homework for Thursday Sections 10-13, 18-19, Boundless PostGIS Tutorial http://workshops.boundlessgeo.com/postgis-intro/

23. Homework 23 Homework: quick overview--demo

24. Tip: Loading PostGIS layers in QGIS 24 I’ve found the DB Manager to work best (Database  DB Manager).

25. Tip: Loading PostGIS layers in QGIS 25 I’ve found the DB Manager to work best (Database  DB Manager). Click and drag layers to add to map. SQL window is awesome...

26. Tip: DB Manager SQL Window 26 DB Manager SQL window is awesome...

27. Tip: DB Manager SQL Window 27 DB Manager SQL window is awesome...

28. Tip: Getting PostGIS views to work in QGIS 28 This will not work in QGIS because QGIS requires a primary key CREATE OR REPLACE VIEW orangeline AS SELECT nyc_subway_stations.geom, nyc_subway_stations.color, nyc_subway_stations.name FROM nyc_subway_stations WHERE nyc_subway_stations.color::text = 'ORANGE’

29. Tip: Getting PostGIS views to work in QGIS 29 Add the red highlighted code to make a fake primary key CREATE OR REPLACE VIEW orangeline AS SELECT nyc_subway_stations.geom, nyc_subway_stations.color, nyc_subway_stations.name, row_number() OVER() AS id_qgis FROM nyc_subway_stations WHERE nyc_subway_stations.color::text = 'ORANGE’