Is there a tool that supports extracting a small region from a bigger GTFS feed? Google's Transitfeed library contains a Merge tool but no Extract/Clip tool, as far as I can see. Other libraries I've found can only read and plot data but don't support manipulation.
Background info: The Transitfeed Feedvalidator shows a lot of errors for my GTFS file. I want to extract my region of interest to assess the local quality.
Recommendations on Twitter pointed me to FME which has both a GTFS reader and a writer. My simple workflow consists of a GTFS reader (bottom left), Shapefile reader (top left, for the area of interest polygon), a clipper and a GTFS writer for the output (only writing the stops and shapes files for now but eventually I'll want all files):
The issue so far is that the output shapes content (orange points) does not contain all the input points (green) which are within the yellow area of interest:
Using "Create Aggregates" = "No", the clipped shapes seem complete
but the stops definitely are not