Line across hillshade output

[jflowernet]

Bringing this issue across from the whiteboxR repo:

• https://github.com/giswqs/whiteboxR/issues/66#issuecomment-1077247236

Essentially, running hillshade on the attached raster in EPSG:4326 resulted in a line across the hillshade output. Reprojecting it into another crs then running hillshade resolved the issue, but it's still not clear why the issue exists since other EPSG 4326 rasters work fine with hillshade (including the demo raster). @brownag suggesting posting the issue here.

I have also tried running the whitebox tool hillshade from the command line resulting in the same issue with a line across the output.

Might be just some oddity with this particular raster, but thought I'd post it here just in case there is a bug. Many thanks for the excellent tools! dem.tif.zip

[Afrancioni]

Hello @jflowernet, thanks for raising this issue. We are aware of this issue, in fact we do have an in place solution but has not been applied to the Hillshade tools in WhiteboxTools. In our most recent stable release of WBT (i.e. 2.1), for certain tools like tools like Slope, Aspect, ProfileCurvature, TangentialCurvature, PlanCurvature, and TotalCurvature, they have been updated to use the more robust 5x5 3rd order bivariate polynomial method of Florinsky (2016) for rectangular grid DEMs, and the 3x3 method, also described by Florinsky (2016), for DEMs in geographic coordinates.

Our next stable release of WBT will have this fix implemented. However for now, the temporary fix like you said is re-projecting the current layer. I will keep the issue open until we release a new version.

[jflowernet]

Ok, great to hear a fix on the cards @Afrancioni.

Thanks again for whitebox tools!