I have a drainage basin (watershed; 21,000 ac/9551 ha) with two points of
interest on the main creek draining that basin. These points are
approximately in the center of the basin, not at the outlet. I'm working
with a 5m DEM map (re-sampled from the original 10m resolution) for all
analyses. Using the easting and northing of these two points I want the area
each drains.
The r.flow module generates flow lines, flow lengths, and contributing
upslope areas. I don't know that this is what I want because I don't know
how to interpret the resulting maps and whether the density map shows all
contributing areas.
In addition to learning how to interpret r.flow results I'd like to learn
if there's a more appropriate module (or modules) to calculate the
information I need.
Thanks,
Rich
On Tue, 9 Feb 2010, Rich Shepard wrote:
The r.flow module generates flow lines, flow lengths, and contributing
upslope areas. I don't know that this is what I want because I don't know
how to interpret the resulting maps and whether the density map shows all
contributing areas.
To be specific: I've attached a tarball of three maps, each a portion of
the r.flow outputs: flow lines, flow line lengths, and flow line density.
I'd greatly appreciate learning how to read these maps.
The two important points are the left triangles; the one on the right is a
local weather station.
Thanks,
Rich
(attachments)
r.flow.output.tgz (42.9 KB)
On Tue, 9 Feb 2010, Rich Shepard wrote:
I have a drainage basin (watershed; 21,000 ac/9551 ha) with two points of
interest on the main creek draining that basin. These points are
approximately in the center of the basin, not at the outlet. I'm working
with a 5m DEM map (re-sampled from the original 10m resolution) for all
analyses. Using the easting and northing of these two points I want the area
each drains.
This I can get from r.water.outlet.
The r.flow module generates flow lines, flow lengths, and contributing
upslope areas. I don't know that this is what I want because I don't know
how to interpret the resulting maps and whether the density map shows all
contributing areas.
I would really appreciate someone teaching me how to interpret and use the
output maps from r.flow. Small samples are attached to the follow up message
I sent yesterday.
Rich