I'm working with a raster map that looks like this:
Do you know any way to select the red/blue spots or ideally put a points on them? I've been browsing web and qgis help for a while now, but I haven't found anything useful as of yet.
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Sometimes I face similar issues, though I do need to get polygons from the images. My current solution is as follows:
info toolto get the specific RGB values of the areas of interest
raster calculatorto change the value of all areas of interest to 1 while the rest of the image is 0 (e.g.
image@1=255 AND image@2=167- this gives all pixels with RGB 255,167,xxx out as 1 while the rest becomes 0).
contourdialogue to convert the black-and-white image to contourlines.
centroidsof the polygons.