ChicagoCrime

predictive modeling for crime rates in Chicago wards

Convert from "Community Area" to "Ward"

Definitions for "community areas" in Chicago can be downloaded as GIS shapefiles. The shapefile file data/chicomm.shp comes from http://www.lib.uchicago.edu/e/collections/maps/chicomm.zip

Some discussion of how to convert from shapefiles to more general purpose polygons is given in http://www.quora.com/How-can-I-convert-a-shapefile-to-a-lat-long-polygon-array-for-use-in-Google-Maps

Download, build, and install the GDAL and OGR utilities from http://www.gdal.org/ogr2ogr.html

./configure ; make; sudo make install

Download, build, and install the GEOS utilities from http://download.osgeo.org/

./configure ; make; sudo make install

Install the lxml package from http://lxml.de/ and the shapely package from https://pypi.python.org/pypi/Shapely based on instructions in http://osxastrotricks.wordpress.com/2010/07/19/install-python-shapely/

Next, we convert the shapefile to KML, then parse the KML to construct Shapely polygons as "LinearRings", based on http://toblerity.github.io/shapely/manual.html#linearrings

ogr2ogr -f "KML" foo.kml data/chicomm.shp
./src/py/shape.py foo.kml