pysochrone

pysochrone is a simple Python script for creating isochrone maps. Isochrones are curves of equal travel time from a certain point of origin. Really this can be used for any type of isoline (aka contour) map. For more information:

• http://en.wikipedia.org/wiki/Contour_line
• http://wiki.openstreetmap.org/wiki/Isochrone

Code is heavily borrowed from the Quantum GIS Contour plugin.

Requirements

• Python
• numpy
• matplotlib
• Shapely
• OGR
• pgRouting (optional)

Use

The contour module has a class Contours which creates contour lines or filled contour polygons from an OGR compatible datasource. A cgi script, isochrone.py, uses this class to provide a RESTful service

Todo

• Include simple Dijkstra algorithm to compute shortest path tree to remove the need for a PostGIS/pgRouting database
• Allow download of OSM data on demand (for small areas)
• Provide more options, such as changing grid size
• Provide more methods, such as alpha shapes or buffered roads