Hi, Can someone explain to me how ArcGIS deals with the symbolization of the adjoint catchment polygons. For example I have an area of interest that I have run Arc Hydro tools over to portray the catchment areas as polygons. The adjoint catchment output has 7 large catchments when symbolized, although, in the attribute table, there are 86 polygons. Arc seems to show the largest on top, but all the others are still underneath. Consequently when you symbolize with unique values all 86 polygons show up, not good for legends when you only want the largest. Is there any way to just have a dataset of the largest catchments, without having to manually export them?
The main objective of the AdjointCatchment feature class is to speed up performance for watershed delineation. It does not need to be visible in the map. It represents the aggregated catchments upstream of any given catchment. However, if you to visualize a subset, you could setup a definition query to show only the features meeting your specified criteria (Definition Query tab in the Properties window).