[GRASSLIST:2651] v.patch (category IDs and descriptions)

Christof Bigler christof.bigler at colorado.edu
Mon Feb 16 15:19:52 EST 2004


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




More information about the grass-user mailing list