I have a raster of 36 classes of the land cover in South Africa. However, I only need 4 of these classes and create a polygon out of these 4 classes combined. I have now used the raster calculator to generate a raster where 0 = the values/classes I don't need and 1 = the 4 classes I need.
How can I polygonize just the value 1 from this raster? Or, how can I polygonize the 4 classes out of the land cover layer directly?