[postgis-users] PostGIS Raster Decimal?

Pierre Racine Pierre.Racine at sbf.ulaval.ca
Mon Mar 14 08:44:17 PDT 2011

I'm very aware of the problem. Will try to fix it the best we can.

Why not testing ST_MapAlgebra and give us your feedback? It is still to document but the specifications are in this page:



From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Andreas Forø Tollefsen
Sent: 14 mars 2011 11:24
To: PostGIS Users Discussion
Subject: Re: [postgis-users] PostGIS Raster Decimal?

Hi Pierre.

Yes. I think that would be an appropriate temporary fix.
Still, a bit problematic when working with climate data which very often include decimal digits and often have weekly and monthly rasters for 100's of years :)

Good luck.


2011/3/14 Pierre Racine <Pierre.Racine at sbf.ulaval.ca<mailto:Pierre.Racine at sbf.ulaval.ca>>

This is a well known problem. See ticket http://trac.osgeo.org/postgis/ticket/650

I will discuss this problem with Frank this week at the code sprint in Montreal.

For now you can use some GIS with map algebra capability to multiply your raster by 10 before importing or test our brand new ST_MapAlgebra function (still to debug).


>-----Original Message-----
>From: Pierre Racine
>Sent: 14 mars 2011 10:55
>To: Pierre Racine
>Subject: FW: [postgis-users] PostGIS Raster Decimal?
>From: postgis-users-bounces at postgis.refractions.net<mailto:postgis-users-bounces at postgis.refractions.net> [mailto:postgis-users-<mailto:postgis-users->
>bounces at postgis.refractions.net<mailto:bounces at postgis.refractions.net>] On Behalf Of Andreas Forø Tollefsen
>Sent: 14 mars 2011 10:53
>To: PostGIS Users Discussion
>Subject: [postgis-users] PostGIS Raster Decimal?
>Hi. Again.
>I have been working on some raster data in PostGIS lately.
>However, i have some issues with the raster values become integer after importing the sql to postgis.
>For instance this procedure:
>C:\prio_grid\source\gpw>c:\python26\python c:\prio_grid\script\raster2pgsql.py -
>r c:\prio_grid\source\gpw\lrc30p90\glp90ag30\w001001.adf -t gpw90 -s 4326 -o gpw
>90.sql -I -M
>Then to database:
>C:\prio_grid\source\gpw>psql -h -d priogrid -f gpw90.sql
>Querying this data:
>SELECT gpw90.gid, ((gpw90.gpw90val).val) AS gpw90
>INTO popgrid
>FROM (SELECT priogrid_land.gid, ST_Intersection(gpw90.rast, priogrid_land.centroid) AS gpw90val FROM
>gpw90, priogrid_land WHERE ST_Intersects(priogrid_land.centroid, gpw90.rast)) AS gpw90
>WHERE gpw90.gid = 139303
>GROUP BY gid,((gpw90.gpw90val))
>gid; gpw90
>The value in the original raster is:
>Question is then. How can i ensure that raster remain decimal and not integer after this import and
>query process?
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