[GRASS-user] Re: some interesting tools for working with LAS format

[Dylan Beaudette]

Hi,

On Tuesday 03 July 2007 06:40, Bernhard Reimar Hoefle wrote:
> Hi!
> I've already used the LAS Tools by M. Isenburg: easy to compile and no
> dependencies. It would be great to have the full functionality within
> GRASS.

Glad to head that these tools are simple to compile, and tips? I did not see a 
Makefile, perhaps one has to spell it out manually?

> The tool "las2txt" can be used to generate ASCII Files that can be imported
> with r.in.xyz or v.in.ascii. The LAS file format does offer a lot of
> possibilities for data storage and hence data extraction
> (http://www.lasformat.org/).

Great. Thinking this over a bit, it might make more sense to beef-up the 
r.in.xyz (binning) module, as opposed to direct import of LAS data to vector 
points. This would allow for the import of > 3 million points without 
overloading the vector engine. However, if the lastools have subsetting and 
gridding support, then they might be a useful alternative to the r.in.xyz 
approach. Reading and writing LAS files would be a nice addition to GDAL in 
my opinion, which would allow the more general v/r.in.gdal style.

> I can think of some modules:
>  * r.in.las
>  * v.in.las
>  * v.out.las
>

As a start we can include references to the LAS tools in the relevant man 
pages and wiki, with build and useage examples. This would get new users up 
to speed on the 'toolchain' approach to processing data with GRASS+external 
tools.

> An easy version would be to ask M. Isenburg, if we can use his code and
> build shell scripts around his executables.
> A second solution - with much more effort - would be to integrate his code
> into GRASS C modules.

While this is always an option, I think that by generalizing things a bit 
further (via a GDAL/ogr driver) or using the LAS tools as a pre-processing 
step would be the best way forward.

What do you think?

Cheers,

Dylan

>
> Bernhard Höfle
>
> > LAS is a format commonly used to store lidar data. here is a link I found
> > this
> > afternoon regarding some opensource tools which can convert to and from
> > LAS.
> >
> > http://www.cs.unc.edu/~isenburg/lastools/
> >
> > it does not look like it is a simple compile -- I don't see any make file
> > or instructions...
> >
> > Perhaps we can talk to these people, and integrate a LAS reader into
> > GRASS, or
> > better yet figure out how to use it with r.in.xyz!
> >
> > cheers,
> >
> > dylan
>
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