[GRASS-user] v.dissolve
Hi I'm trying to join all adjacentareas in vector into one (in fact all area are adjacent, and I want to convert it to one huge area) I tried to use v.dissolve and I expected If I do nto specify column all borders will disolve, but it not work (I have no column with the same attribute) The solution I have used is to add empty column and fill it with ther same value (both by db.execute) but it became more complicated If I have almost 200 vectors Is there any more natural or more simple solution? If no please let me known Jarek ___ grassuser mailing list grassuser@grass.itc.it http://grass.itc.it/mailman/listinfo/grassuser
Re: [GRASS-user] v.dissolve
Jarek Jasiewicz wrote: I'm trying to join all adjacentareas in vector into one (in fact all area are adjacent, and I want to convert it to one huge area) I tried to use v.dissolve and I expected If I do nto specify column all borders will disolve, but it not work (I have no column with the same attribute) The solution I have used is to add empty column and fill it with ther same value (both by db.execute) but it became more complicated If I have almost 200 vectors Is there any more natural or more simple solution? If no please let me known v.dissolve (v.extract -d) is designed to dissolve common boundaries between areas with the same category number. So you could use v.category to remove all category numbers, then re-add them with only category 1 (v.category step=0) and then do the dissolve. If you want to get original categories back you could use v.distance, but there is then the question of which cat to use if different area cats were merged into one. hope that helps, Hamish __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ grassuser mailing list grassuser@grass.itc.it http://grass.itc.it/mailman/listinfo/grassuser
Re: [GRASS-user] v.dissolve
Hamish wrote: Jarek Jasiewicz wrote: I'm trying to join all adjacentareas in vector into one (in fact all area are adjacent, and I want to convert it to one huge area) I tried to use v.dissolve and I expected If I do nto specify column all borders will disolve, but it not work (I have no column with the same attribute) The solution I have used is to add empty column and fill it with ther same value (both by db.execute) but it became more complicated If I have almost 200 vectors Is there any more natural or more simple solution? If no please let me known v.dissolve (v.extract -d) is designed to dissolve common boundaries between areas with the same category number. So you could use v.category to remove all category numbers, then re-add them with only category 1 (v.category step=0) and then do the dissolve. If you want to get original categories back you could use v.distance, but there is then the question of which cat to use if different area cats were merged into one. hope that helps, Hamish __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com thanks but in general it is very similar to solution I proposed - generally addational steps are required t hanks again Jarek btw: in v.dissolve script probably lacks g.remove at the end to remove temporary vector ( i.e something like dissolve_6786) ___ grassuser mailing list grassuser@grass.itc.it http://grass.itc.it/mailman/listinfo/grassuser
Re: [GRASS-user] v.dissolve
Jarek Jasiewicz wrote: btw: in v.dissolve script probably lacks g.remove at the end to remove temporary vector ( i.e something like dissolve_6786) Yes, you are right. Now fixed in CVS. Hamish __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ grassuser mailing list grassuser@grass.itc.it http://grass.itc.it/mailman/listinfo/grassuser
