[pdal] Point cloud viewer in QGIS

[Martin Dobias]

Hi Alvaro

On Tue, Jul 7, 2020 at 10:56 AM <ahuarte47 at yahoo.es> wrote:
>
> Are you thinking about implementing a new QgsVectorDataProvider where the new QgsFeatureIterator yields the point cloud as QgsFeature instances?
>
> If you allow me an idea, the QgsVectorDataProvider, or even the QgsFeatureIterator, could create on-the-fly a PDAL PipelineManager instance with the necessary PDAL readers, and initially some PDAL filters to consider the input parameter of current QgsFeatureRequest. Then the iterator could fetch the points implementing a new PDAL writer[1] as final stage of the pipeline.
>
> All field info structure of the point could be read from the writer or from the last filter[2] (method: virtual void addDimensions(PointLayoutPtr layout);) of the Pipeline.

Thanks for your thoughts. The plans so far were to create a completely
new layer type, so it would not be "just" a new data provider for
vector layers, it would be rather a new "point cloud layer". There are
some similarities with ordinary point vector layers, but I think the
sheer amount of points needs a different approach - the existing QGIS
vector layer API is not really built to deal with many
millions/billions of points efficiently.

But talking about pipelines, it's a good idea, also suggested by
Howard, that rather than supporting only plain input files, QGIS could
use pipelines to allow some extra functionality similar to GDAL's
virtual rasters.

Regards
Martin