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List:       grass-user
Subject:    [GRASS-user] r.water.outlet and longitude / window issue
From:       Andy Wickert <wickert () colorado ! edu>
Date:       2011-06-28 5:00:11
Message-ID: BANLkTim+3kMKGQU2bapf0bKvB0auO5_esA () mail ! gmail ! com
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Hi GRASS user-list,

I think that I have run into a bug in either the computational window
definition or the r.water.outlet program (or maybe something else) that has
to do with defining degrees West as either positive (East-longitude >180) or
negative.

What happens is that, for example, I type:
r.water.outlet drainage=$watershed_direction basin=temp_basin easting=196
northing=60 --verbose --overwrite

And GRASS returns:
WARNING: Warning, ignoring point outside window:
         -164.0000,60.0000

This occurs no matter whether I specify the longitude as a positive
East-longitude (as above), as a negative value (e.g.,-164), or as, e.g.,
164W. (196E is not allowed).

The problem is not my window definition, which includes the point in
question:
proj:       3
zone:       0
north:      73:00:30N
south:      49:59:30N
east:       144:59:30W
west:       162:59:30E
cols:       3121
rows:       1381
e-w resol:  0:01
n-s resol:  0:01
top:        1
bottom:     0
cols3:      3121
rows3:      1381
depths:     1
e-w resol3: 0:01
n-s resol3: 0:01
t-b resol:  1

When I use r.what, it gives me East-longitudes (values >180) for regions to
the East of the 180 meridian. But r.water.outlet insists on switching
everything to negatives no matter what input I give it, which I think is a
source of the problem.

The strangest thing about this is that I ran into this problem while
following a routine that I had written several months ago in Bash; last
time, I ran r.water.outlet on North America (all in degrees-west land) with
no problems at all. I just checked the computational region (window) files
for that run, and they look very similar to the ones I am using now. I have
no clue why I didn't run into this problem back then / why it is cropping up
now; both computers are running GRASS 6.4.1 on Ubuntu Linux.

Anyway, if anyone has any suggestions, I'm all ears. Many thanks in advance,

Andy Wickert

[Attachment #5 (text/html)]

<div>Hi GRASS user-list,</div><div><br></div><div>I think that I have run into a bug \
in either the computational window definition or the r.water.outlet program (or maybe \
something else) that has to do with defining degrees West as either positive \
(East-longitude &gt;180) or negative.</div> <div><br></div><div>What happens is that, \
for example, I type:</div><div>r.water.outlet drainage=$watershed_direction \
basin=temp_basin easting=196 northing=60 --verbose \
--overwrite</div><div><br></div><div>And GRASS returns:</div> <div><div>WARNING: \
Warning, ignoring point outside window:</div><div>         \
-164.0000,60.0000</div></div><div><br></div><div>This occurs no matter whether I \
specify the longitude as a positive East-longitude (as above), as a negative value \
(e.g.,-164), or as, e.g., 164W. (196E is not allowed).</div> <div><br></div><div>The \
problem is not my window definition, which includes the point in \
question:</div><div><div>proj:       3</div><div>zone:       0</div><div>north:      \
73:00:30N</div><div>south:      49:59:30N</div> <div>east:       \
144:59:30W</div><div>west:       162:59:30E</div><div>cols:       \
3121</div><div>rows:       1381</div><div>e-w resol:  0:01</div><div>n-s resol:  \
0:01</div><div>top:        1</div><div>bottom:     0</div> <div>cols3:      \
3121</div><div>rows3:      1381</div><div>depths:     1</div><div>e-w resol3: \
0:01</div><div>n-s resol3: 0:01</div><div>t-b resol:  \
1</div></div><div><br></div><div>When I use r.what, it gives me East-longitudes \
(values &gt;180) for regions to the East of the 180 meridian. But r.water.outlet \
insists on switching everything to negatives no matter what input I give it, which I \
think is a source of the problem.</div> <div><br></div><div>The strangest thing about \
this is that I ran into this problem while following a routine that I had written \
several months ago in Bash; last time, I ran r.water.outlet on North America (all in \
degrees-west land) with no problems at all. I just checked the computational region \
(window) files for that run, and they look very similar to the ones I am using now. I \
have no clue why I didn&#39;t run into this problem back then / why it is cropping up \
now; both computers are running GRASS 6.4.1 on Ubuntu Linux.</div> \
<div><br></div><div>Anyway, if anyone has any suggestions, I&#39;m all ears. Many \
thanks in advance,</div><div><br></div><div>Andy Wickert</div>



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