[GRASS-user] r.mapcalc: compare two maps [RESOLVED]

[Rich Shepard]

On Thu, 30 Mar 2017, Rich Shepard wrote:

> Germane to what Markus M. wrote, "The point locations used to edit the
> original DEM are probably wrong (not close to the center), ..." I now
> think that's where I made one mistake.

   Nope. I zoom in to isolate those 4 cells in in the blocked map. No matter
where within the cell I click the elevation is the same.

   However, ... I'm now wondering if the issue is the elevation in feet
rather than meters.

   The source DEMs were run through r.proj to convert from feet to meters.
This converted the coordinates but apparently not the elevations. If Itzi
wants all input in SI units then having elevations in feet with rainfall in
mm/hr would certainly get the model's briefs in a twist.

   If having elevation data range from ~147 to ~168 feet rather than ~45m to
~51m would produce incorrect results then I suppose I need to multiply both
input maps (open and blocked) by 0.305 using r.mapcalc, then run both models
again.

  Comments? Thoughts?

Rich