DEM to Polygon
Working on a DEM (30m x 30m raster) of a large area, I need to find out the area (polygons) which is greater that 5,000 hectares and within which average slope is less than 10 degree. The shape of the area/polygon- more it is towards square or reactangle better it is.
I cannot figure out which step would enable me to achieve this. Can you experts guide me or give me hint, please?