I have several presence maps (rasters values 1 and 0) from different species. They are all from South America, but they do not have the same extend (i.e., different sizes).
So, I am trying to develop a "richness" map, trying to sum all these values, which would give me a value of the number of species for each pixel (from 1 to 6, as they are six species).
However, when trying to use the raster calculator and other grid analysis tools, this fails because: 1) it shows me only a map with areas where they all overlap (this happens with raster calculator), or 2) fails because the layers are different (different extent, this happens with grid sum, and other analysis tools).
How can I have a map that sums all pixels values, and includes the areas of all the different presence maps?