[GRASSLIST:2200] Re: Another problem with r.proj
rshepard at appl-ecosys.com
Sat Jul 28 14:29:22 EDT 2001
On Sat, 28 Jul 2001, Eric G. Miller wrote:
> > PROJ_UNITS:
> > unit: unknown
> > units: unknowns
> > meter: 1
> Does it help if you change the PROJ_UNITS to?
> unit: meter
> units: meters
> meter: 1.0
I didn't pick this up until I sent the response. I just changed it and,
no, it makes no difference.
> Also, it looks like you need to specify the input "mapset" for the
> location (i.e. "spc").
Tried that, too. I posted to the list as well as to Len when he suggested
> Actually, the datum transformation needs to be done via geodetic
> coordinates following the inverse projection from UTM. Unfortunately,
> the projection routines in GRASS don't do this at the present.
Would it be a Good Thing at this point for me to use r.out.ascii and
v.out.ascii on these data sets and then use the USGS 'proj' program? I don't
know if that does datum convertions as well as projection conversions.
> It may or may not be easier to use i.rectify to transform the DEM --
> provided you can find suitable control coordinates. (hint: select 6 or 8
> points spread across the input source; transform them to geodetic
> coordinates; use m.datum.shift to get the corresponding datum shifted
> geodetic coordinates; project the coordinates to your target projection;
> voila, you have control points in both coordinate systems).
I can't see this as being easier. :-)
So, does it look like a bug in r.proj to you?
Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc. (TM)
2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com
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