determining error of DEM

[Rado Bonk]

Hi Markus,
> you may contact
> Maria Brovelli <maria at ipmtf4.topo.polimi.it>
> She is working on such topics. She and her
> institute organized the "Italian GRASS Day" recently
> in January.
> 
> Kind regards
> 
>  Markus Neteler
> 
> PS: Did you generate the DEM from stereo pairs within GRASS
> or externally? I am very interested in such topic.
DEM was generated by SPOT Corp. And originaly was in ERDAS IMAGINE raster
format.

Rado

> 
> On Sat, Mar 25, 2000 at 06:29:25PM -0600, Rado Bonk wrote:
> > Hi GRASSusers,
> > I need to examine the DEM error, before using the DEM for future
> > analysis.
> > I have a big 140x 80km,20mx20m resolution elevation grid from vertically
> > highly exaggerated montain area. Vertical exaggeration is almost
> > 5000m, and slope angles go up-to 85-90 degrees. The grid was computed from
> > stereo pair of two satellite images, and control points from ground
> > photogrammetry were used to decrease the error in DEM.
> > Using just visual control in nviz2.2 I have found that, on same places are
> > smooth-like areas (very smooth surfaces) among the typical terrain
> > features. Since accuracy of the whole DEM is good enough (elevation error
> > is less than 10m) I would like just to examine these local errors in DEM.
> > Any ideas?
> > 
> > Thanks,
> > 
> > Rado
> > 
> > Rado Bonk
> > Geography and Geology
> > UNO, Nebraska, 68182-0199,
> > rado at cosmos.unomaha.edu
> > 
>