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Published 20 hours ago • verified publisher icon der-stefan

advice: Gaps in hillshading

Open robshep opened this issue 6 years ago • 9 comments

Hi,

I wonder if anybody knows why i'm seeing little gaps and missing edges in the hillshading?

image

robshep avatar May 23 '18 20:05 robshep

i have the same bug on a fresh otm server installed following the how to for dummies. [edit] : i found the same glitches here on this old comment (2016) of another issue : https://github.com/der-stefan/OpenTopoMap/issues/54#issuecomment-265221707

guillaumebof avatar May 25 '18 22:05 guillaumebof

Yes, those glitches come from the DEM. Here is some current information about NASADEM: https://gis.stackexchange.com/questions/267134/what-is-nasadem-and-when-it-will-be-released

der-stefan avatar May 26 '18 12:05 der-stefan

how does opentopomap.org succeed to remove those glitches ? by using another source of DEM files or by processing the viewfinderpanoramas ones ?

guillaumebof avatar May 26 '18 13:05 guillaumebof

@der-stefan

just re-asking @guillaumebof 's question. Does OpenTopoMap.org tiles use this new NASDEM or the original ones described in the HOWTO?

Here is the same shot from my earlier comment, but taken from opentopomap.org

image

@guillaumebof did you find a solution to the glitches?

robshep avatar Aug 03 '18 08:08 robshep

@robshep no i don't succeed to remove the glitches... so i move back to openstreetmap for my project. but i'm interested to know the workaround of the official opentopomap !

guillaumebof avatar Aug 03 '18 21:08 guillaumebof

We use the DEM kindly provided by opensnowmap, not NASADEM yet.

der-stefan avatar Aug 04 '18 07:08 der-stefan

@der-stefan The problem doesn't seem to come from the DEM. Indeed:

  • when using the SRTM 1 arc second global DEM (the one used by OpenSnowMap), I also have the voids
  • when I open my tifs in Photoshop, there are no voids

Sounds like a problem in the tif usage to me. Am I wrong?

@robshep Did you manage to fix the problem?

timautin avatar Aug 07 '18 12:08 timautin

Allright, I found a solution, see https://github.com/der-stefan/OpenTopoMap/issues/185

timautin avatar Aug 07 '18 17:08 timautin

Hi all,

I have the same issue on my own tileserver built with the help of the How To from Stefan. Still the same after I changed the interpolation from bilinear to bicubic. To be sure that all tiles gonna be new rendered I deleted all the metatiles. Strangly I have still a hillshading after I deleted all the tiff from the ~/OpenTopoMap/Mapnik/dem Directory?!?

Any ideas how can I remove (or suppress) these annoying gaps and glitches? My dem are taken from http://srtm.csi.cgiar.org/srtmdata (these are processed datas and shall have no gaps)

Thank you in advanced

Laverdista668 avatar Nov 22 '19 20:11 Laverdista668