Ticket 650 was fixed in PostGIS and in the GDAL trunk. The ticket says "New GDAL polygonize function implemented in GDAL release 22476 ( http://trac.osgeo.org/gdal/changeset/22476). Please, update your GDAL copy to a release"
What version of libgdal do you have? > -----Original Message----- > From: [email protected] [mailto:postgis-users- > [email protected]] On Behalf Of Andreas Forø Tollefsen > Sent: Thursday, October 27, 2011 7:59 AM > To: PostGIS Users Discussion > Subject: Re: [postgis-users] Raster geomval return integer > > Replying to my own post. > > Just to confirm my belief I used the raster calculator in QGIS and calculated > 'rast*100'. > Then imported it to postgis and ran the query again: > > SELECT gid,(foo.geomval).val, > CAST(SUM(ST_Area((foo.geomval).geom)) AS decimal(8,5)) as area, > CAST(SUM(ST_Area((foo.geomval).geom))/0.25*100 AS decimal(6,3)) as > percentarea FROM (SELECT p.gid, ST_Intersection(ST_SetSRID(p.cell,4326), > ST_SetSRID(r.rast,4326), 1) AS geomval FROM mountain r, priogrid_land p > WHERE ST_Intersects(ST_SetSRID(p.cell,4326), ST_SetSRID(r.rast,4326),1)) AS > foo WHERE gid = 183230 AND (foo.geomval).val >= 0 GROUP BY gid, > (foo.geomval).val ORDER BY gid; > > Result: > 183230;74;0.00000;0.000 > 183230;33;0.00694;2.778 > 183230;80;0.00000;0.000 > 183230;16;0.00694;2.778 > 183230;9;0.00694;2.778 > 183230;100;0.04167;16.666 > 183230;73;0.00694;2.778 > 183230;89;0.00694;2.778 > 183230;71;0.00694;2.777 > 183230;22;0.00694;2.778 > 183230;35;0.00000;0.000 > 183230;48;0.00000;0.000 > 183230;59;0.00694;2.778 > 183230;0;0.13889;55.555 > 183230;12;0.00000;0.000 > 183230;6;0.00694;2.778 > 183230;1;0.00695;2.778 > > I can of course do this with any raster including a decimal pixel value, but > I really > would like to not have to. > > Any ideas? > > Andreas > > > 2011/10/27 Andreas Forø Tollefsen <[email protected]>: > > Hi all, > > > > I have been working on this issue previously, but now we have updated > > to rev 8001 and the ticket 650 is fixed. > > Hence, I wanted to see if I can calculate the average pixelvalue > > within my grid cells (.5x.5 decimal degrees). > > > > However, I now experience that any value above 0 becomes 1, and i do > > not get the actual averaged value. > > I also tested to group by the polygonized pixel value, and this > > revealed that everything other than 0 is 1. > > According to my raster this is not correct, since I have many other > > values within the cells borders (see jpg). > > > > I have tried to use the ST_Value(rast, ST_SetSRID(ST_Point(lat,long)) > > and this give me the correct pixel values. > > However, I do not understand what is giving me integer values using > > the query below. > > > > Any ideas on what is wrong with my query? > > > > Query: > > SELECT gid,CAST(((foo.geomval).val) AS decimal(8,6)) AS mntval, > > CAST(SUM(ST_Area((foo.geomval).geom)) AS decimal(8,5)) as area, > > CAST(SUM(ST_Area((foo.geomval).geom))/0.25*100 AS decimal(6,3)) as > > percentarea FROM (SELECT p.gid, > > ST_Intersection(ST_SetSRID(r.rast,4326), > > ST_SetSRID(p.cell,4326)) AS geomval FROM mountain r, priogrid_land p > > WHERE ST_Intersects(ST_SetSRID(p.cell,4326), ST_SetSRID(r.rast,4326))) > > AS foo WHERE gid = 183230 AND (foo.geomval).val >= 0 GROUP BY gid, > > (foo.geomval).val ORDER BY gid; > > > > Result: > > 183230;1.000000;0.06945;27.778 > > 183230;0.000000;0.18055;72.222 > > > > > > Best, > > Andreas > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
