I'm using QGIS 3.8. I have dowloaded GLOBCOVER 2009 raster land cover map and ecoregions shapefile. Polygon of ecoregions are used for mask to cut raster file. On new layer
r.report was performed to measure land cover types.
I have found difference between area of polygon and excised raster layer. For example, Ural montane forest and tundra ecoregion is 175533 km2 and the result of r.report:
Total area is 116576,1 km2. Difference is 58956,88 km2. What causes the difference?