Is there a way to iterate over lines and their vertices using python? I'm new to GRASS GIS, and it looks like there are ways to read raster (for numpy), but I don't see a direct way to access coordinates and topology for vectors.
I know that I can access binary data but it does not seem right. I can convert vector feature to db for later use with vector_db_select but it is an extra operation for conversion and I have no data what was what (how can I walk a graph?).
Also when I try to run
v.to.db map=merged_single@PERMANENT layer=1 option=coor units=meters columns=cat
This option requires at least two columns
Finished with error
For instance in ArcGIS I can easily iterate over elements using SearchCursor. I wonder if there is anything similar in GRASS GIS?
After reading GRASS GIS manual, it looks like one has to use C library and functions prefixed with
Another possible choice probably is to use OGR as it somewhat supports GRASS GIS, but its python bindings are not perfect. It all seems a bit awkward as QGIS so nicely works with all formats from GUI so the inability to access all that from python (which is the official scripting language) seems like a huge shortcoming unless I missed something. Perhaps it will be better in the future.