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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