malnunn

Stream Definition: any value for Area SqKm resets FAC threshold to the default 1%

Discussion created by malnunn on Apr 2, 2014
Latest reply on Jan 28, 2015 by Playa
Hi

I've run the Basic Dendritic Terrain Processing workflow and noticed an issue with the Stream Definition geoprocessing tool (Arc Hydro 10.2).

Despite setting my FAC parameter to 2000, the output Str has actually defaulted to 1% (~120 000). I have isolated this and tested the tool on its own, and it appears that having the optional parameter Area SqKm set to anything except blank results in this behaviour - I guess something to do with the automatic calculation of the Area SqKm parameter from Number of Cells and vice versa. This is confirmed in the geoprocessing history showing both input parameters as the default 1%, not the values entered (although if run as a model, geoprocessing history will show the inputs as the values specified, but still run it with the default 1%)

In editing the workflow in ModelBuilder, it also seems that if there are values are set in both fields for the tool, upon reopening the tool both parameters are reset to the default 1% FAC and derived Area SqKm. However, if number of cells is specified and Area SqKm is manually set to blank, the correct value will be saved and preserved.

Obvious workaround is to ensure that the Area SqKm is blank and just specify the number of cells. Just wondering if this is a known issue?

Cheers
Mal

Outcomes