ST_MapAlgebraNgb definitely cannot help resolve neighboring tiles. -bborie
On 07/02/2013 01:33 PM, Hugues François wrote: > Hello Bborie, > > Thanks for your answers. I have requested our team to migrate to postgis2.1 > since beta version been released but unsuccessfully. I hope things will move > with the official release. I fall in love with these "new sexy features" and > others. > > Awaiting for this moment, I will look further at st_MapAlgebraNbr but I'm > afraid I won't manage to deal with different tiles. > > Regards, > > Hugues > > -----Message d'origine----- > De : [email protected] > [mailto:[email protected]] De la part de dustymugs > Envoyé : mardi 2 juillet 2013 19:09 > À : [email protected] > Objet : Re: [postgis-users] Pixels' neighbors > > Hugues, > > Another possibility if you have PostGIS 2.1 is ST_Neighborhood(). > > http://www.postgis.net/docs/manual-dev/RT_ST_Neighborhood.html > > -bborie > > On 07/02/2013 09:47 AM, Hugues François wrote: >> Hello, >> >> Given a one band raster made of numerous tiles and a point geometry from >> which I select one pixel, I would like to compare its value with its (8) >> neighbors' values. For now I do that with st_value(rast, geom) and playing >> with point coordinates (x +/- pixel width and y +/- height) : it works fine >> but it is very slow and I have to make a loop to compare selected pixels' >> values with their neighbors until I reach a certain value. >> >> What I would like is to do all that only with raster but I don't see how to >> compare one pixel value with its neighbors (within the same tile or into a >> neighbor tile). I assume I miss something and this is obvious for some of >> you, so if you could give a hand, i would be sincerely grateful. >> >> Regards, >> >> Hugues. >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users >> > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > _______________________________________________ > postgis-users mailing list > [email protected] > http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list [email protected] http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
