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

[maning sambale]

After struggling with this without any solution for the past 2 dyas.
I will try r.cross



On Tue, Nov 25, 2008 at 4:07 PM, maning sambale
<emmanuel.sambale at gmail.com> wrote:
> Nearly there but not quite:
>
> The final column should combine the values from the 2 columns, am I
> right that concat doesn't work with dbf?
>
> So this doesn't work
> echo "UPDATE vectormap SET c_COVER = a_COVER || a_value" | db.execute
>
> cheers,
> maning
> On Tue, Nov 25, 2008 at 2:34 PM, maning sambale
> <emmanuel.sambale at gmail.com> wrote:
>> 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
>>>
>>>
>>> --
>>> |---------|----------------------------------------------------------|
>>> | __.-._  |"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/ |
>>> |---------|----------------------------------------------------------|
>>>
>>
>>
>>
>> --
>> |---------|----------------------------------------------------------|
>> | __.-._  |"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/ |
>> |---------|----------------------------------------------------------|
>>
>
>
>
> --
> |---------|----------------------------------------------------------|
> | __.-._  |"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/ |
> |---------|----------------------------------------------------------|
>



-- 
|---------|----------------------------------------------------------|
| __.-._  |"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/ |
|---------|----------------------------------------------------------|