Markus:
I try to merge the 100km tiles of the CORINE vector
landcover maps which are delivered in SHAPE format.Due to the tiling there are annoying boundaries now
when patching the tiles together. I then tried to
reclass and dissolve them based on the landuse
code to no avail.
..
# dissolve
v.extract -d clc2000_tn_bl_recl out=clc2000_tn_bl_dissolved
v.extract -d type=area
^^^^^^^^^^^
then it works with box.asc. Note this is what the v.dissolve script
does already: your box.asc dissolves correctly with v.dissolve,
including preserving the boundary's cat number(s).
without type=area, it decides to keep the boundary here:
vector/v.extract/extract.c line ~ 271
else if ( type_only && field > 0 ) /* type and field only */
{
/* line */
if ( type_match && field_match ) write = 1;
it correctly skips writing the boundary as part of an AREA due to the
dissolve, but decides to write it anyway as a BDY as it is a categorized
feature.
I'm not convinced this is a bug. v.extract is doing what you told it to do.
(type= default: point,line,boundary,centroid,area,face [with cat])
FWIW, some debug msgs:
when boundary has a cat, field_match is set to 1: (field==layer)
field_match = Vect_cat_get(Line_Cats_Old,field,&tmp);
box.asc (line 4 is your boundary cat 2)
D2/2: line = 4 field=1 type_only=1
D2/2: type_match = 1 field_match = 1 cat_match = 0
D2/2: left_area = 1 left_field_match = 1 left_cat_match = 0
D2/2: right_area = 2 right_field_match = 1 right_cat_match = 0
D2/2: writing line 4. LINE (field 1)
D2/2: write = 1
box.asc with boundary cats removed.
D2/2: line = 4 field=1 type_only=1
D2/2: type_match = 1 field_match = 0 cat_match = 0
D2/2: left_area = 1 left_field_match = 1 left_cat_match = 0
D2/2: right_area = 2 right_field_match = 1 right_cat_match = 0
D2/2: write = 0
Hamish