[pdal] Help tutorial how use PDAL Libraries

[Howard Butler]

On May 30, 2013, at 7:52 AM, Nicolas Mantelier <nicolas.mantelier at spaceyes.fr> wrote:

> Hello everybody,
>  
> I try to use PDAL api for produced an OSG driver that allow to load unlimited size of Lidar file.

Let me attempt to rephrase. You want to feed point cloud data from PDAL to some sort of OSG consumer?

> Where can I have some example or tutorial,
> I find http://www.pointcloud.org/tutorial/reading.html but not that I am looking for.

If the above is true, can you state in what ways it is currently deficient?

> I find http://www.lidarnews.com/content/view/8879/199/ pretty good one, but don’t know where and how, data is accessible; in PointBuffer ? in Schema ?
>  
> How render PDAL structure with OSG someone already working on it?

I don't think anyone is working on OSG consumption of PDAL data, so you're blazing new ground here.
 
> There is an equivalent to http://www.liblas.org/tutorial/cpp.html for pdal api ?

Unfortunately, no, however there are more complete applications that drive various things inside of ./apps. More precisely, see pcpipeline.cpp for example code how to read PDAL data from any XML pipeline (as demonstrated in test/data/pipeline). pcinfo.cpp and pc2pc.cpp also show some more things you can do with PDAL. None of this has been put into a cogent document, however.

> More specific question:
>  
> I want to render my scene with octree, there is some spatial index which allow to display fast a part of lidar file?

PDAL provides a filter that leverages FLANN to do fast neighbor lookups, but there is no octree. libLAS has an octree, however, and this could be repurposed into a PDAL filter if you had enough desire.

> I see Bounds http://www.pointcloud.org/api/cpp/bounds.html but I don’t know if that work with index, or if all point is tested before render or not ?
>  
> If someone have example of simple code using PDAL and can give it to me. It will be very find.

The most complete usage examples for PDAL exist in ./apps and ./tests/unit

Hope this helps,

Howard