Vector donuts, how are they represented?

GRASS GRASS user
1

Listers, Can somebody tell me how the v.out/in.ascii format
would describe a polygon with a smaller polygon wholly inside it,
where the smaller polygon (the hole) has a different category
than the larger polygon (the donut)? I want to get the area of
the donut to not include the hole, and for both to be separate
polygons with separate categories.

For that matter, I'd like to know how arc/info does it in
whatever way is compatible with v.in.arc.

Cheers, Peter Briggs

Normally pbriggs@laurel.ocs.mq.edu.au
Temping as micromet@rata.geog.indiana.edu

2

Peter Briggs writes,

Listers, Can somebody tell me how the v.out/in.ascii format
would describe a polygon with a smaller polygon wholly inside it,
where the smaller polygon (the hole) has a different category
than the larger polygon (the donut)? I want to get the area of
the donut to not include the hole, and for both to be separate
polygons with separate categories.

For that matter, I'd like to know how arc/info does it in
whatever way is compatible with v.in.arc.

Can't we get you to use the raster environment -- life
would be so much easier :wink:

Chris