[GRASS-user] r.flow: units for flow accumulation

Rich Shepard rshepard at appl-ecosys.com
Fri Oct 19 14:55:26 PDT 2018


On Fri, 19 Oct 2018, Rich Shepard wrote:

> Gotcha'. I'll do this instead of using r.flow. (Running r.watershed rather
> than r.flow.)

   Well, this is not working for me (see attached .png). Most of the upper
left area is quite flat, especially east of the river.

   The manual's explanation of negative numbers, that they possibly have
surface runoff from outside the area, doesn't seem likely here because the
drainage basin's watershed divide is the outline of the area.

   I used the -b option in the command (and the -m option on this host) and
ask for ideas on how to get the legend to expand the very narrow non-black
band to show the colors on the map, and ignore all the negative values.

   Also, if there are additional input maps I need to have calculated I want
to learn which ones and how best to prepare them.

Rich


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