vote for improved DEM generation capabilities in ENVI

[Siri Jodha Singh Khalsa]

Only a handful of commercial software packages are available for 
generating DEMs from ASTER data. Each have their strengths and shortcomings.
A DEM generation module was added to ENVI (ITT Visual Information 
Solutions) a little over a year ago and we at NSIDC have found that it 
performs well and is somewhat more user-friendly than PCI Geomatica 
Orthoengine.  However, one thing it lacks, which PCI has, is control 
over hole filling and interpolation. While the overall quality of DEMs 
generated by ENVI is excellent, major anomalies (peaks, depressions) can 
occur where the correlation between image pairs fails and the algorithm 
interpolates across voids using poor elevation data on the perimeter of 
these voids.

I have requested to have a score channel added in the DEM generation 
process. This would be a separate layer that carried information about 
the quality of the DEM at each pixel location. Such a layer would allow 
the user to selectively eliminate data that was suspect before 
interpolating or doing further analysis.  This was entered as change 
request 44575. However, it has not yet been worked on.

I then made a simpler request:  to have the option of leaving the voids 
and allowing the user to edit the raw DEM before applying whatever 
smoothing and interpolation they thought was best.  I got this response 
from ITT VIS:
> I will add your suggestion of a no smoothing/interpolation option to the existing feature request.  If you know of any other individuals who use ENVI and whose work is negatively impacted by this issue, please pass along their names and I can add them to the list of affected customers.  To be honest, there is a more or less direct relationship between the number of affected customers and the speed with which a requested feature is implemented.
Thus the reason for this email.  I am asking anyone who is an ENVI user 
to write to support at ittvis.com <mailto:support at ittvis.com> and request 
these features be added to the ENVI DEM extraction module.

Thanks!

-- 
Siri Jodha Singh Khalsa, Ph.D.
L-3 Communications GSI, Senior ECS Consultant
National Snow and Ice Data Center
University of Colorado
Boulder, CO 80309-0449 Phone: 1-303-492-1445 
http://cires.colorado.edu/~khalsa 

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