Holes in DEM

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Josh Williams

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Jun 30, 2022, 3:35:02 PM6/30/22
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I've been producing DEMs derived from CTX stereo pairs on Mars and have encountered a significant amount of holes in the DEMs. Do you all have any recommendations on how to properly fill them or have any advice on how to blend with other data products such as MOLA topography or HRSC DEMs? Thank you in advance. 

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Josh M. Williams
PhD Candidate
EPS UNM

Alexandrov, Oleg (ARC-TI)[KBR Wyle Services, LLC]

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Jun 30, 2022, 3:43:44 PM6/30/22
to Josh Williams, ames-stereo-pi...@googlegroups.com
While holes can be filled, there is a good chance they show up for a reason, and it is a sign of quality issues with your inputs. One potential issue could be the illumination difference among your two images. You may want to examine just how similar your L.tif and R.tif are (in stereo_gui). Then, I will suggest using --stereo-algorithm asp_mgm, if that's not what you are using. Then, if you are using ASP 3.1.0, the latest, you may want to search for the convergence angle value in your stereo_pprc log file (in the output directory). If that is too small, say under 5 degrees, it can cause issues. 

Lastly, if you really want to fill the holes, note in point2dem the option --dem-hole-fill-len. You can also use --search-radius-factor 2 (or 3) to fill things a bit more. But these would be cosmetic fixes. If your inputs are good, normally the DEM comes out quite filled and seamless. In a produced DEM the tool dem_mosaic can fill holes as well. 


From: ames-stereo-pi...@googlegroups.com <ames-stereo-pi...@googlegroups.com> on behalf of Josh Williams <jos...@gmail.com>
Sent: Thursday, June 30, 2022 12:34 PM
To: ames-stereo-pi...@googlegroups.com <ames-stereo-pi...@googlegroups.com>
Subject: [EXTERNAL] Holes in DEM
 
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