[GRASS-user] v.overlay attribute table problem

[Didrik Pinte]

Hi,

I'm using v.overlay to intersect two layers : mpnetwork and
management_polygones.

The output layer is base_cells.

I'm wondering why some of the initial attribute values aren't kept in
the outputted merged table :

Vector 14 of management_polygons has a value for area_tot attribute :

GRASS 6.2.0 (ALMERIA):~/Documents/ucl/alert/grass > v.db.select
map=management_polygones column=cat,area_tot where="cat=14"
cat|area_tot
14|1195927.2564

In the merged attribute table, it seems that b_area_tot for b_cat 14 is
null ... :

GRASS 6.2.0 (ALMERIA):~/Documents/ucl/alert/grass > v.db.select
map=base_cells column=cat,a_cat,b_cat,b_area_tot where="b_cat=14"
cat|a_cat|b_cat|b_area_tot
62|18|14|0
63|2|14|0
65|2|14|0
67|41|14|0
70|35|14|0
73|1|14|0
86|13|14|0
87|8|14|0
105|31|14|0
113|32|14|0
118|39|14|0
119|37|14|0
121|40|14|0
131|3|14|0
132|6|14|0
133|28|14|0

How is this possible ? The merged attribute table should keep all the
input values according to the documentation. Am I wrong ?

Didrik

PS : running Grass 6.2.0 on a Debian system


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