Dear list,
I would like to patch two vector maps together and keep their attributes
(with the same columns but not in identical order) using v.patch with
flag -e.
Both maps have cats starting with 1. Hence, I thought I use v.category,
option 'add' to add a fixed (large enough value) to the categories and
creating a second layer to keep the attribute values like this:
v.category input=map1 layer=2 type=line output=map1_cat option=add
cat=100001
Then I add a table to layer 2 with a column for the old cat:
v.db.addtable map=map1_cat layer=2 columns="cat_lyr1 integer"
Next, I fill this column (I want to use this column to be able to later
join the attributes from the original maps):
v.to.db map=map1_cat layer=2 type=line option=query columns=cat_lyr1
query_column=cat
Finally, I would like to use v.patch with flag e. However, this works
only for the table in layer 1. Hence, I wanted to use v.categroy to
change the layer numbers:
v.category input=map1_cat layer=2,1 type=line output=map1_cat2
option=chlayer
And get the warning: WARNING: Database connection and attribute tables
for concerned layers are not changed
I tried to first drop the table in layer 1 with:
v.db.droptable -f map=map1_cat
and then use v.category but that results in the same warning as before.
Layer 2 is still layer 2.
Can anybody please explain to me what is wrong? I am still struggling to
get my head around categories and layers but I thought I found a way to
do it correctly.
Thanks a lot,
Mira
--
Dr. Mira Kattwinkel
Quantitative Landscape Ecology
Institute for Environmental Sciences
University of Koblenz-Landau
Fortstraße 7
76829 Landau
Germany
Phone: + 49 6341 280-31553
Office: Building I, Room 2.02
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