If the file is in a raster by id number, you could run r.stats
to determine which are above the minimum size. The -a switch will
report size in square metres.
After that, it should be easy to rig up a reclass using r.reclass,
reclassing the smaller polygons to 0. If you need to do this
repeatedly, then a script to rig the reclass rules would not be hard
to code.
Angus Carr.
I hope you have a simple answer to my hopefully simple question. I have a
file with around 1000 polygons. I need to have displayed or selected only
those polygons that are less than 1544 acres. This file exists in vector
and raster format. What command in GRASS would be used to
accomplish this?