Would LASTools add anything to the conversation? I do believe they
re-order the file (but I've not used it).
-----------------
Randal Hale, GISP
North River Geographic Systems, Inc
http://www.northrivergeographic.com
423.653.3611 rjh...@northrivergeographic.com
<mailto:rjh...@northrivergeographic.com>
twitter:rjhale
http://about.me/rjhale
On 01/29/2014 08:25 AM, Jean-Roc Morreale wrote:
Most lidar files are not spatially ordered so with a sequential read
you will end up reading the whole file, it's like accessing a untiled
unpyramided bigtiff : painful.
Le 2014-01-29 13:52, A Huarte a écrit :
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.
Alvaro
-------------------------
DE: Jean-Roc Morreale <jr.morre...@enoreth.net>
PARA: qgis-developer@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
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