I merged two vector maps with v.patch in=map1.v,map2.v out=map3.v
map1.v has 988 categories, map2.v 362, and map3.v again 988 categories, apparently with the first 362 categories having the same ID.
v.report map1.v type=area:
# | description | count
2 1 1
3 2 1
4 1 1
5 3 1
...
v.report map2.v type=area:
# | description | count
2 1 1
3 2 1
4 2 1
5 3 1
...
v.report map3.v type=area:
# | description | count
2 1 2
3 2 2
4 1 2
5 3 2
...
This is quite confusing for new Grass users. It looks, as if there are non-unique category IDs in map3.v. And it looks that in map3.v the category descriptions of map2.v are overwritten by category descriptions of map1.v.
But since Grass uses an internal ID, I assume that the category descriptions of map2.v are (internally) not overwritten.
Can anybody enlighten me?
Christof