artemp/trac2github — Issue #751: Invalid shapefile indexes should be detected and throw
Author: artemp
Created: 2011-10-09 20:49:43+00:00
State: open
Labels: Shapefile_Input_Driver

Between Mapnik 0.7.1/0.7.2/trunk various fixes to geometry handling in the shapefile driver appear to have made indexes subtlety incompatible. This is not unexpected, but the result is silent failures (missing features from renders).

In one test case all features would be rendering once, then on subsequent tile requests (with the map/datasource kept in memory) tiles would be blank. This silent failure makes finding the cause difficult. We need to either version the shapefile indexes or otherwise try harder to detect their validity.