The Government of Canada provides a nifty dataset called CanVec* which contains all the features you'd find on a standard NTS map in Shapefile format. The data is provided as zip archives, each corresponding to a map sheet in the NTS system.

The trouble arises when you want to extract a specific feature type across several sheets; you have to navigate a deep folder hierarchy, opening, searching and extracting files as you go.

I made this little Python script to make the task easier. It navigates the CanVec directory (in whatever form it exists on your drive), finds the files that match your search criterion and extracts them to a temporary folder. Then it creates an SQL file containing the instructions to create and populate a table in a PostGIS database with the data. This last step requires that shp2pgsql exist on your PATH.

Here's the invocation:

python canvec.py FO_1030009 output.sql ./canvec contours_m canvec

This tells canvec.py to find files whose names match the string FO_1030009 (metric contours). It searches for archives in ./canvec and saves temporary files by default in /tmp. Then it outputs a file called output.sql which will create and poplate a table called contours_m in the canvec schema (defaults to public).

* http://geogratis.cgdi.gc.ca/geogratis/en/product/search.do?id=5460AA9D-54CD-8349-C95E-1A4D03172FDF