I am going to establish flow accumulation raster of an area in Norway.
I have downloaded a lot of LAS-files and created a DEM with some replacement polygons like water. Further on I want to use the hydrology tools to establish a raster of flow accumulation.
When making a watershed raster from the Watershed tool, is it important to include the total area that the watershed is involved in?
-- Or is it possible to cut out a study area from the DEM and establish watersheds from this? How does this cutting affect the result?