I'm working with a very large set of polylines - contour data - to be rendered with Mapnik. (The contours are generated using gdal_contour from SRTM data.)
At present I'm storing them in PostGIS and Mapnik reads them from there. However, I'm not convinced this is the best use of space or CPU.
Would there be a performance hit if Mapnik read the shapefiles directly (with an .index file, of course)?
What would be the best way to minimise storage requirements for such a large dataset? Are there any other formats I should be considering?