Hello Michael, Thanks a lot for your quick reply, Regards. Agossa. Michael Bedward wrote: > > Hi Agossa, > > It might be easiest for you to get the backing image from grid > coverage and use JAI methods for the masking and calculation. In JAI > parlance, masking is referred to as defining a "region of interest", > ROI, which may be a shape or pixel-based (e.g. ROI based on coverage > cells with a particular value). > http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/ROI.html > http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/ROIShape.html > > Then you can either use a JAI iterator to count value occurrences > within the ROI... > http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/iterator/RectIterFactory.html > > ...or the JAI histogram operation to count occurrences of all values > within the ROI. Both can deal with multiple bands. > > An example using an iterator and an ROI based on a second grid > coverage. It assumes that the two coverages have the same bounds... > > RenderedImage dataImg = cov1.getRenderedImage(); > RenderedImage maskImg = cov2.getRenderedImage(); > > // create an ROI based on all pixels in maskImg with value > // >= threshold > ROI roi = new ROI(maskImg, threshold); > > RectIter iter = RectIterFactory.create(dataImg, null); > int numBands = dataImg.getSampleModel().getNumBands(); > int[] values = new int[numBands]; > int[] count = new int[numBands]; > for (int i = 0; i < numBands; i++) count[i] = 0; > > int y = roi.getBounds().y; > do { > iter.startPixels(); > int x = roi.getBounds().x; > do { > if (roi.contains(x, y)) { > iter.getPixel(values); > for (int i = 0; i < numBands; i++) { > if (values[i] == searchValue) { > count[i]++; > } > } > } > x++ ; > } while (!iter.nextPixelDone()); > y++ ; > } while (!iter.nextLineDone()); > > > Michael > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by: > SourcForge Community > SourceForge wants to tell your story. > http://p.sf.net/sfu/sf-spreadtheword > _______________________________________________ > Geotools-gt2-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > >
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