[GRASS-user] r.threshold: Where is the output?

[Rich Shepard]

On Thu, 21 Jun 2012, Margherita Di Leo wrote:

> To now, r.threshold doesn't manage negative values, so if the warning
> appears, there is no output.

madi,

   Using absolute values of the r.watershed accumulation map as input to
r.threshold provides a suggested r.basin threshold of 5297. As you write in
the wiki entry, this is both a suggestion and a reflection of uncertainty in
the meaning of the threshold.

   Using this threshold value in the shell script for the 7 sub-basins,
r.basin halts on the calculation of the Horton indices for one basin, and
does not produce a parameter .csv file for a second sub-basin. The base DEM
map is used by r.basin, not the accumulation map with all positive values.

   Can you suggest a strategy I can apply to generate different threshold
values to see how to allow r.basin to complete its run on those last two
sub-basins? Is there a reason for the threshold value to be the same for
each sub-basin?

Thanks,

Rich