[please always cc the list to let everyone profit of the discussion]
On 15/11/07 11:10, Dr. Manuel Seeger wrote:
Thanks Moritz,
but I think I did not explain clear enough.
v.to.db calculates the values for each category (here this is each
polygon), but I need the sum of values for different classes, which are
composed by a changing number of polygons. I want to know the area of
each class.
After running v.to.db, you can run a select on the classification
column. Something like:
echo "select sum(area) from TABLE group by ClassificationColumn" | db.select
If your classification information is in integer form, you can also use
v.reclass:
v.reclass in=OrigMap out=ReclassMap Column=ClassificationColumn
and then v.to.db on ReclassMap.
Moritz
how?
Thank you!
Manuel
Moritz Lennert schrieb:
On 15/11/07 08:27, Dr. Manuel Seeger wrote:
Hello list,
I have a polygon map with a huge table, in which some columns give
the information about a classification of the single polygons (these
are represnted by single categories). I would like to calculate e.g.
the sum of areas belonging to each class. How can I do this
I tried a way by extracting the class needed indiviadually,
generating a new tabel and so on, but it seems to be quite
complicated. Is there a more simple way to get the results?
v.to.db with option=area ?
Moritz
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