The ArcGIS Sort tool creates a new feature class with features sorted by geometry. For example, it can number features IDs from north to south, etc. Is there a way to renumber the
cat field in a GRASS vector map based on geometry in a similar way?
In GRASS GIS, you can use v.reclass to achieve this goal. For each target category (ID) you can define a where statement to use attribute values to perform the job. See the manual for an example. Other tools like v.to.db help you to populate the attribute table properly for this task.