[postgis-users] PostGIS Raster Decimal?

Pierre Racine Pierre.Racine at sbf.ulaval.ca
Wed Mar 16 06:53:43 PDT 2011


Yes, this is ticket 837

http://trac.osgeo.org/postgis/ticket/837

Jorge, are those numerous warning normal?
________________________________________
From: postgis-users-bounces at postgis.refractions.net [postgis-users-bounces at postgis.refractions.net] On Behalf Of Andreas Forø Tollefsen [andreasft at gmail.com]
Sent: Wednesday, March 16, 2011 9:24 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] PostGIS Raster Decimal?

Is the above memory issue known for the ST_MapAlgebra function?
Did you experience this Regina?

I will try with some other rasters.
The WARNING lines are just a sample. I think it went through a couple of thousands before it ran out of memory.
Is it not strange that the truncated values are the same as the original values?

Andreas

2011/3/15 Andreas Forø Tollefsen <andreasft at gmail.com<mailto:andreasft at gmail.com>>
Hi Pierre,
I got memory issues as well.
I tried with this query:
SELECT ST_MapAlgebra(rast, 'rast*10') INTO algtest FROM gpw90;


WARNING:  Pixel value for 32BF band got truncated from 47519.1 to 47519.1
WARNING:  Pixel value for 32BF band got truncated from 185494 to 185494
WARNING:  Pixel value for 32BF band got truncated from 28485.1 to 28485.1
WARNING:  Pixel value for 32BF band got truncated from 10927.1 to 10927.1


ERROR:  out of memory
DETAIL:  Failed on request of size 19.

********** Error **********

ERROR: out of memory
SQL state: 53200
Detail: Failed on request of size 19.

2011/3/14 Paragon Corporation <lr at pcorp.us<mailto:lr at pcorp.us>>
Pierre,

Actually the single raster version is documented.  Though I did run into memory issues -- so still think we need some work on that.

http://www.postgis.org/documentation/manual-svn/RT_ST_MapAlgebra.html

Regina
http://www.postgis.us



________________________________
From: postgis-users-bounces at postgis.refractions.net<mailto:postgis-users-bounces at postgis.refractions.net> [mailto:postgis-users-bounces at postgis.refractions.net<mailto:postgis-users-bounces at postgis.refractions.net>] On Behalf Of Andreas Forø Tollefsen
Sent: Monday, March 14, 2011 2:03 PM
To: PostGIS Users Discussion
Cc: Pierre Racine

Subject: Re: [postgis-users] PostGIS Raster Decimal?

Hi Pierre,

I will check it out tomorrow and give some feedback.

Cheers,
Andreas

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

http://trac.osgeo.org/postgis/wiki/WKTRaster/SpecificationWorking02

Pierre

From: postgis-users-bounces at postgis.refractions.net<mailto:postgis-users-bounces at postgis.refractions.net> [mailto: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.

Best,
Andreas

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

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).

Pierre

>-----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 192.168.1.55 -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))
>;
>
>Gives:
>gid; gpw90
>139303;39849
>
>The value in the original raster is:
>39849.2
>
>Question is then. How can i ensure that raster remain decimal and not integer after this import and
>query process?
>
>Thanks.
>Andreas
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