[Qgis-developer] Lidar data into QGIS

A Huarte ahuarte47 at yahoo.es
Wed Jan 29 04:52:25 PST 2014

I think but using a quadtree approach there is a problem, and it is none other than the construction of the quadtree itself for so big data.

IMHO I would use a specific provider (with a specific featureiterator) reading sequentially the LAS file and discarding points before fetch it to renderer using the RectangleFilter of current FeatureRequest. It avoid create many-many QgsFeature's that after are discarded in renderer side.

I use this technique in a personal viewer, and after first read of file (the file is cached in SO), the following drawings are quite fast.


> De: Jean-Roc Morreale <jr.morreale at enoreth.net>
>Para: qgis-developer at lists.osgeo.org 
>Enviado: Miércoles 29 de enero de 2014 13:32
>Asunto: Re: [Qgis-developer] Lidar data into QGIS
>Can it performs fast enough to display hundred millions points or 
>billions at once ? Does it leverage a quadtree approach ?
>Le 2014-01-29 12:55, A Huarte a écrit :
>> yes, it can be implemented on renderer level (Martin Dobias propose
>> it) or on featureiterator level similar to current simplification
>> classes for line and polygons
>> I think it is pending for a test of performance
>> Best Regards
>> Alvaro
>Qgis-developer mailing list
>Qgis-developer at lists.osgeo.org
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