[GRASS-dev] question about any July changes in hydrology functions

[Glynn Clements]

Michael Barton wrote:

> Beginning sometime in the 1st half of July, we¹ve started getting some weird
> artifacts in surface process models that we¹ve been developing using r.flow,
> r.slop.aspect, and r.mapcalc. The results are linear zones of deposits that
> seem to follow cell grid lines. This wasn¹t happening previous to early
> July. We¹ve scouring our scripts and so far can¹t find anything to account
> for this changed behavior. It acts like some kind of dynamic resolution
> change artifact, but we are not doing anything to cause this AFAICT.
> 
> It is probably something squirrelly in our scripts that we just  haven¹t
> seen. But I thought I go for a long shot and ask if there have been any
> changes that might affect the behavior of r.flow or r.slope.aspect recently.
> I didn¹t see anything obvious in the commit list archives, but may have
> missed a library change of some kind.

$ cvs diff -D 2007-07-01 -D 2007-07-15 raster/r.mapcalc raster/r.slope.aspect raster/r.flow
cvs server: Diffing raster/r.mapcalc
cvs server: Diffing raster/r.slope.aspect
cvs server: Diffing raster/r.flow

Assuming that your dates are correct, it isn't the programs. Extending
the comparison to lib/{gis,vector,bitmap,btree,rowio,segment} (the
only libraries which those programs use directly) doesn't show
anything which looks remotely relevant.

I can only suggest checking out and compiling "before" and "after"
versions, and examining any intermediate data produced by your
scripts.

-- 
Glynn Clements <glynn at gclements.plus.com>