[GRASS-user] SQL Queries

[Markus Neteler]

Kevin,

On Thu, Jul 27, 2006 at 05:09:18PM -0400, Slover, Kevin wrote:
>    Ok, looking for a SQL guru out there...
> 
>    
> 
>    Want to see if something is even possible or not using GRASS (using 5.4)
> 
>    
> 
>    Here is the situation... I have 2 files, once containing xyz pts, and
>    another containing polygons.  I am wondering if there is a way to use a
>    sql query to find the average elevation for a given polygon?
> 
    
In GRASS 5 I don't know, but in GRASS 6 you can simply use
v.stats.rast which is giving you these results in a single step
(without learning SQL :-)

http://grass.itc.it/grass61/manuals/html61_user/v.rast.stats.html

 
>    I am trying right now to use MapInfo to do this query, but it doesn't like
>    the amount of points I am query (> 1,500,000) and knowing that GRASS is
>    much better at processing and dealing with larger files, wondered if a
>    query like this is possible..

I think that GRASS should work with 3 million points and more.

Markus