On a previous article called "OpenStreetMap to GeoJSON", I explained how to extract Polygons from OSM using an online tool provided by from OSM France. And, on this article, I’ll explain how do that yourself directly using the OSM API and Python.

This also explains the basic concepts I used to write the osmexp tool, to export OSM elements into GeoJSON from the command-line.

Use OpenStreetMap as your repository of geometries, and export them in the more convenient GeoJSON format. This technique only works with geometries with area (Polygon and MultiPolygon), points and lines break the exporting tool used here.

The JSON format is the backbone of current Internet protocols and APIs, and this article contains a list of tools to make a better use of it from the command-line, without the need of writing complex programs to read, search, parse, transform and transmit JSON data.