I'm having some difficulty adding raster layers. I'm trying to create a species richness map and I was thinking of layering them via the calculator. The files I have are individual species distributions (which are just patches of 1 grids), and I have a main raster of the map of the location (which are patches of 0 grids). Now, when I add the layers on raster calculator (irrespective of order), I end up with just the patches of 1 and the larger map just disappears. This would still happen if the values were 1 and 2 respectively, the grid cells for the main map would just disappear anyway.
What I want is to still have those grids with the value 0 so it would be uniform for all the species so I would be able to overlay all of them at once and get a map of the richness. The size of the cells are the same, and they are under the same projection. I just dont know what might be the reason.
Does anyone know why this happens/what I can do about it?
Any help would be greatly appreciated. Thank you.