[GRASS-user] Re: combining and evaluating vector dbf values

[maning sambale]

Hi,

Answering partially to my problem.

I found a way to update columns by from a criteria of another column

like this:
v.info -c overlay_trainingANDforest2002_sq
lDisplaying column types/names for database connection of layer 1:
INTEGER|cat
INTEGER|a_cat
INTEGER|a_value
CHARACTER|a_label
INTEGER|a_COVER
INTEGER|b_cat
CHARACTER|b_ID
CHARACTER|b_TYPE
INTEGER|c_COVER

v.db.update map=overlay_trainingANDforest2002_sql col=c_COVER
value=112 where="a_Cover=112

And It's really fast for 100K records!  Now, how do make an sql
expression by evaluationg multiple columns?

cheers,
maning


On Tue, Nov 25, 2008 at 12:01 PM, maning sambale
<emmanuel.sambale at gmail.com> wrote:
> Hi,
>
> Any help in doing the following:
>
> I have a combined vector in grass using v.overlay
>
> I now have a dbf table with the following
> a_value = integer
> a_value2 = integer
> b_value = string
>
> Now I want to combine the categories in another column (c_value) like :
>
> evaluate b_value, a_value, a_value2
> then assign c_value from a lookup table
>
> the lookup table is a set of integer values based on the various
> combinations of b_value, a_value, a_value2
>
> Any ideas doing this in GRASS or oodbase?
>
> cheers,
> maning
>
>
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-- 
|---------|----------------------------------------------------------|
| __.-._  |"Ohhh. Great warrior. Wars not make one great." -Yoda     |
| '-._"7' |"Freedom is still the most radical idea of all" -N.Branden|
|  /'.-c  |Linux registered user #402901, http://counter.li.org/     |
|  |  /T  |http://esambale.wikispaces.com/ |
| _)_/L I http://epsg4253.wordpress.com/ |
|---------|----------------------------------------------------------|