Even though watershed delineation is a quite popular matter here, I have what seems to be a somewhat unusual demand.
I start with a DEM which is constituted of a series of craters, all centered on one point which is the lowest part of the crater.
What I want to to, is to obtain the drainage basin of each crater.
I know how to delineate watersheds using ArcGIS' Hydrology tools, but they are best suited for 'open' hydrological systems (flows try to reach the exterior of the raster).
Here is the result I obtain. How comes some of my drainage basins are obviously wrong? Why is Arcgis so lazy that its scope is limited to the rectangle limited by the four most extreme (N-S-W-E) points?
Therefore, my question is the following: is it possible to automatically delineate the watershed basin and set the center of my craters as the targets where my flows should go?
Thanks in advance for your help!
[Edit : added Arcgis output for clarity]