[GRASS-user] v.in.lidar finds 0 points in GRASS 7

[Markus Metz]

On Thu, Feb 20, 2014 at 2:24 AM, Michael Moore <stuporglue at gmail.com> wrote:
> Hello,
>
> I think I'm doing something wrong with importing lidar data in GRASS 7.
>
> My data is a laz file from the state of Minnesota.
>
> The complicating factor is that the EPSG code is set incorrectly --
> EPSG:32715 / UTM 15 S instead of EPSG:26715/UTM 15 N. My region is set to
> the correct 26715.
>
> I am using the GUI, but the command that it generates is
>
> v.in.lidar -p -o --overwrite input=/data/3542-27-22.laz output=test
>
> The output is:
>
> Over-riding projection check

Something is wrong here:

> Importing 0 points...

because I get

Importing 12588100 points...
 100%
12588100 points imported

If you compiled GRASS 7 from source, you could go to vector/v.in.lidar and run
make clean
make

and check for any errors or warnings

> Building topology for vector map <test at stuporglue>...
> Registering primitives...
> 0 primitives registered
> 0 vertices registered
> Building areas...
> 0 areas built
> 0 isles built
> Attaching islands...
> Attaching centroids...
> Number of nodes: 0
> Number of primitives: 0
> Number of points: 0
> Number of lines: 0
> Number of boundaries: 0
> Number of centroids: 0
> Number of areas: 0
> Number of isles: 0
> 0 points imported
>
> lasinfo reports 12588100 points.
>
>
> I'd be happy to get this imported either through the command line or the
> GUI, but my goal is to understand enough about GRASS to script the creation
> of a state-wide DSM from LiDAR data.

You can also use r.in.lidar method=min or first convert the .laz file
with las2txt, then use r.in.xyz method=min. With the r.in.* modules,
the region should be set first, taking particular care about the
resolution. Something like

# set the region extents to the lidar point cloud extents
g.region n= s= e= w=
# align the region again to the target resolution
g.region res=<target_resolution> -a

HTH,

Markus M
>
> Thanks,
> Michael Moore
>
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