Bug report #15943
Hillshade renderer artifacts
Status: | Open | ||
---|---|---|---|
Priority: | Normal | ||
Assignee: | - | ||
Category: | Symbology | ||
Affected QGIS version: | 3.0.0 | Regression?: | No |
Operating System: | Debian | Easy fix?: | No |
Pull Request or Patch supplied: | No | Resolution: | |
Crashes QGIS or corrupts data: | No | Copied to github as #: | 23859 |
Description
Borders of cells are visible. See attached.
Possibly more apparent in master, but present since the beginning.
History
#1 Updated by Giovanni Manghi over 7 years ago
- Regression? set to No
- Easy fix? set to No
#2 Updated by Johannes Kroeger almost 7 years ago
That's a highly zoomed-in view (much closer than 1:1 scale) of a hillshaded raster with Nearest Neighbor resampling. I am not sure if this is a bug.
A simple workaround (or solution?) is to set the resampling to Bilinear or Cubic.
#3 Updated by Johannes Kroeger almost 7 years ago
- File nn vs bilinear.png added
Example image at about 3:1 scale.
#4 Updated by Alister Hood almost 7 years ago
- Description updated (diff)
Also affects 2.18.16.
I am pretty sure we can call it a bug - there is no reason a hillshade should need cell borders, and if you create an actual hillshade layer (e.g. using the gdal hillshade tool) it won't have them.
#5 Updated by Alister Hood almost 7 years ago
Johannes Kroeger wrote:
A simple workaround (or solution?) is to set the resampling to Bilinear or Cubic.
It is a workaround, not a solution ;)
Also, unless I'm missing something there is no way to get rid of these artefacts in a 3D map in master.
#6 Updated by Alister Hood almost 7 years ago
Alister Hood wrote:
there is no reason a hillshade should need cell borders
Except they aren't borders as such, they are hillshading applied at the edges of the individual raster cells. I haven't looked at how hillshading algorithms work in gdal or wherever - maybe they actually incorporate smoothing, in which case the solution here would probably be to always enable smoothing for the hillshade renderer.
#7 Updated by Giovanni Manghi almost 7 years ago
- Affected QGIS version changed from master to 3.0.0