Longest Flow Path for Catchments Problems

[JohnScrase]

I have progressed through the Terrain Preprocessing toolbox, from DEM Reconditioning through to Adjoint Catchment Processing, on a DEM sized at 6,587x12,522 30m cells (320mb). However, I am coming unstuck at the Longest Flow Path for Catchments, where the software fails with an error message getting at available memory alloctaion.

I have tried most of the tips and tricks found within this forum (i.e. clearning temporary workspace, increasing Raster rendering allocation, disabling background processing, etc) but with no luck. I think it is due to the large number of catchments I am trying to generate stats for (> 10,000).

Can anyone out there advise on how best to subdivide the data/model to get this information (longest flow paths) out. Utlimate aim is to identify adjoint catchments over 10km2 threshold as providing cumulative catchment areas, and assigning longest flow paths and average basin slope for each of these adjoint catchments? I have read somewhere that it is possible to divide for regional based analysis, but can find no help on how one would go about this.

Any help would be greatly appreciated.

[ChristineDartiguenave]

The Longest Flow Path for Catchments tool is pretty intensive and running it on this number of catchments will take a very long time.
It does run on selected set however so you may be able to process by part.

Why do you need to define lfps for all the catchments? Usually catchments should be defined using the 1% threshold rules and should be in the hundreds. They are used to optimize performance. Having too many of those defeat the purpose.

How many adjoint catchments are you going to end up with for characterization? You may be better off defining lfp for each adjoint directly.

Christine Dartiguenave
Esri Water Resources Team