Hydrology Flow Direction Tool results in stretch (not D8) when DEM is large

[Hemlock_Grove]

Hi,

While using the spatial analyst hydrology toolset on a DEM raster, I am finding that the output of the Flow Direction tool is a black and white stretch (with values outside the range of 1-128 as it should be for D8) when the DEM is 'large.'

If I clip the DEM (and I'm not sure of the threshold here or what it's based on-- small town size seems to work, county-wide is too large) it seems to work property with 8 distinct color classes.

I am filling the DEM prior to running the flow direction. 

Any Ideas?

[Oveys_Ziya]

Hi,

I am facing the same problem. Were you able to solve this?

Thanks