[GRASS-user] r.basin: specifying closing point by geographic coordinates

[Rich Shepard]

On Wed, 24 Oct 2012, Margherita Di Leo wrote:

> As a general remark, you can always give a try with the coordinates that
> you already have, because it can happen that those exactly match the
> extracted river network, even if it is unlikely.

madi,

   These are locations where water and benthic macroinvertebrates were
collected so if they're not exactly on the stream, they can easily be moved
to overlap the line without loss of ecological information.

> By the way, i've never tested the script using lat/lon coordinates, but i
> suppose that you can get some of the parameters in a unit derived from
> degrees, which is not correct, so you need to use metric coordinates in
> order to get a suitable result.

   The original measurements are in lat/lon but after importing to that
locations they were re-projected to the project location which uses the
State Plane Coordinate System projection; the units are in metres.

   I assume that if I provide one set of easting/northing coordinates the
script will run only once and define that specific drainage basin for me.
This assumption will be tested and results forwarded per your request below.

> BTW, if you are willing to make a test on it and send (maybe privately) to
> me the results, I'll appreciate. Thus I'll update the documentation
> accordingly.

   Certainly.

Rich