[GRASSLIST:1810] Re: i.ortho.photo on osx

Richard Greenwood Rich at GreenwoodMap.com
Tue Nov 18 22:11:46 EST 2003

At 10:04 AM 11/18/2003, you wrote:
>Richard, thanks for your response. If you had a similar experience, I am 
>curious to know what happened.  I am not sure that I have a feet to meters
>problem though.  I am projecting from an XY location into an UTM projection.
>The dem elevation units are in meters.  I projected my dem from a lat-long
>location, however the elevation units were meters in that too.  If it isn't
>much trouble, I would be curious to see what your case is.

I am by no means an expert with i.ortho.photo. I have only done two 
projects with it. But I did just revisit the project that gave me some 
difficulty. Initially I was in UTM meters, with a DEM in meters and control 
points in meters, but I was getting no joy. When I converted the DEM and 
the control points to feet it worked correctly. The project fell by the 
wayside, and I had forgotten about it until I read your post.

At the risk of sending you on a wild goose chase, you can test my premise 
fairly easily:
   1. convert your DEM to feet with r.mapcalc dem_feet = dem * 3.2808
   2. convert your CONTROL_POINTS file to feet. (save a copy of your 
existing file then convert the elev field for each row to feet.
Everything else can stay in meters.

Please keep me posted if you choose to try this.


Richard W. Greenwood, PLS
Greenwood Mapping, Inc.
Rich <at> GreenwoodMap <dot> com
(307) 733-0203

More information about the grass-user mailing list