Thanks...see inline Pierre Racine-2 wrote: > >>So would you advise me to get postgis from the trunk, and compile the >>source, or its fine to work with the version from kyngchaos for now? > > Depends if what you want to do is included or/and working fine in this > version. The last version is always better. > >>In terms of the image - well the image pixels all have a certain value >>associated to them (its a probability map actually, so all the values per >>pixel are between 0->1. > > Every images have values associated with their pixels. When its not just > RGB values, it's other values. > > I want to intersect a polygon (region) with this >>image raster and pull out the mean probability depending on which pixels >>were covered. The image is 3.5mb > > This is a pretty small image. You would probably not gain much tiling it > but you can give it a try. In the first case do not add the -k option and > in the second case add -k 25x25. > >>If I don't import -k 1x1, then what is the best way to proceed? That's how >>the image has been produced for me to work with - there is only 1 image. > > You must understand what -k is actually doing. It will cut your raster > into XxX tiles, one tile per row. This fasten most operation on big raster > coverages which is not really your case. "1x1" is not a way to say you > have only one raster... > > Be carefull here as PostGIS raster was not really intented to do this kind > of operation on so small images. It's like using a bazooka to kill a fly. > Many GIS packages will allow you to do this simple operation much easier > than PostGIS... > > Why do you feel the need to use PostGIS for that? >> Ah well I am using PostGIS already, as part of handling other vector data >> sets etc....this raster image is just one side to it - besides, there >> would be other images which would be bigger, and also, one has to start >> somewhere to test whether it works. Before I stumbled upon Postgis >> Raster, the other option was for me to transform the raster image to >> vector data with attributes - but I want to see how well Postgis Raster >> works for me. I need to be able to dynamically query my datasets (e.g. >> vector data + raster images). > > Pierre > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > >
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