Thank you! On Wed, 9 Dec 2020 at 02:37, Nyall Dawson <[email protected]> wrote:
> On Tue, 8 Dec 2020 at 23:59, Andreas Neumann <[email protected]> wrote: > > > > Hi Martin, > > > > Thanks for the explanation. > > > > I confirm that reducing the maximum error helps to remove the artefacts. > WIth 0.5 mm I could still see them at one particular zoom level, but with > 0.4 mm it was completely gone. > > In https://github.com/qgis/QGIS/pull/40504 I've changed the default to > 0.3. > > Thanks for the feedback! > Nyall > > > > > > Thanks a lot, > > Andreas > > > > > > On Tue, 8 Dec 2020 at 13:15, Martin Dobias <[email protected]> wrote: > >> > >> Hi Andreas > >> > >> The artifacts you are seeing are caused by the fact how the Entwine > tool works in the default configuration. When creating the octree index of > point cloud data, points are organized in a hierarchy of nodes (each > containing usually tens of thousands of points), with each level of the > hierarchy having smaller bounding volume and higher density. One > optimization that Entwine does is that if child nodes contain a small > amount of points, they get merged into the parent node in the hierarchy - > in the hope this will lower the number of nodes and therefore also the > number of requests that need to be done. See Entwine configuration [1] for > more details - especially the options like minNodeSize, maxNodeSize, > overflowDepth, overflowThreshold. So the artifacts could be simply fixed by > reindexing the dataset with modified configuration. > >> > >> All that said, maybe none of that is necessary: > >> 1. I would suggest lowering "Maximum error" in Layer styling to e.g. > 0.5 mm or even 0.3 mm (assuming the default point size of 1mm) - this > should be giving you a rendering result with very little holes - it is much > nicer to look at and the artifacts should be gone at all scales (it will > increase the rendering time, but I think it is worth it and I think we > should lower the default maximum error - the higher maximum error was > initially used mainly as a debugging tool for us to see if the point > spacing in the rendered map matches the expectations) > >> 2. For indexing of point clouds, we will be internally using Untwine > [2] - a newer approach (also coming from friends at Hobu!) that has > different configuration and probably won't be showing these artifacts. > Peter is currently working on the integration [3] > >> > >> Regards > >> Martin > >> > >> [1] https://entwine.io/configuration.html > >> [2] https://github.com/hobu/untwine > >> [3] https://github.com/qgis/QGIS/pull/40404 > >> > >> > >> On Tue, Dec 8, 2020 at 10:30 AM Andreas Neumann <[email protected]> > wrote: > >>> > >>> Hi, > >>> > >>> When testing the 2D point cloud renderer I noticed that in certain > scales / zoom levels one can clearly see point cloud tile borders: > >>> > >>> see screenshot at > https://www.carto.net/neumann/temp/point_cloud_artefacts.png > >>> > >>> There seem to be different densities involved in certain regions here, > but clearly they correspond to tile borders. > >>> > >>> Is this an expected artefact? Can this be avoided? > >>> > >>> When I zoom in or out, these artefacts seem to disappear. > >>> > >>> Thanks and greetings, > >>> > >>> Andreas > >>> > >>> > >>> _______________________________________________ > >>> QGIS-Developer mailing list > >>> [email protected] > >>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > >>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > >> > >> _______________________________________________ > >> QGIS-Developer mailing list > >> [email protected] > >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > > > > > > > -- > > > > -- > > Andreas Neumann > > QGIS.ORG board member (treasurer) > > _______________________________________________ > > QGIS-Developer mailing list > > [email protected] > > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > -- -- Andreas Neumann QGIS.ORG board member (treasurer)
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