GRASS LiDAR tools [it was Re: [Liblas-devel] Hello!]

[Howard Butler]

On May 6, 2008, at 6:18 AM, Roberto Antolín wrote:

> Hello,
>
> Mateusz Loskot wrote:
>>> Antolin made the official GRASS lidar plugins.
>>> http://grass.itc.it/grass62/manuals/html62_user/v.lidar.edgedetection.html
>
> Yes, I'm guilty!! :)
> I've done the GRASS LiDAR tools (v.lidar.*), the v.outlier module  
> for outlier removal and one of the many interpolators within GRASS:  
> v.surf.bspline. They are aimed to reckon a DTM from a LiDAR dataset.
>
> Although I "only" imported the modules from GRASS 5.4 to GRASS 6 it  
> was a lot of work cos I had to rewrite and to modify all of them,  
> and only some functions from the old version were left. In some way,  
> I started from the scracth since I didn't know anything about C,  
> programming in general, GRASS nor LiDAR techniques.
>
> Still I'm not very proud of them because there are still lots of  
> bugs and programming errors. Further improvements have to be done  
> specifically in v.lidar.edgedetection. This module is quite slow and  
> the whole procedure can take up to a couple of days, depending on  
> the dataset dimensions and the number of points.

Roberto,

One of the things we would be very interested in before we release  
version 1.0 is how libLAS integrates with other applications like the  
GRASS LiDAR modules.  If there are significant portions of  
functionality missing, we would like to get them added before the big  
stable release.  Our only applications that extensively uses the APIs  
are the ports of Martin Isenburg's utilities that libLAS contains, and  
while these are good for demonstrating what can be done with the  
library, they don't provide a lot of breadth when it comes to  
functionality you might want in software that directly feeds into a  
processing pipeline or visualization tool etc.

Did you have to write LAS reading/writing software as part of your  
effort, or did you dump the LiDAR data to text before consuming the  
data with GRASS and beginning your processing?

Howard