[GRASS-user] lidar data - nnbathy x bspline

[roberto.antolin at polimi.it]

Hi Carlos and all,

> I did some Lidar interpolation with nnbathy and bspline. data has
> ~16.5mill points, and final dem has ~35mill cells.
> while nnbathy did some very nice results (see image), it took ~8hours
> to interpolate. bspline is beautifully fast, did the job in ~1hour,
> but the final dem has many artifacts.
>
> I was wondering how to avoid these artifacts with bspline? or with we
> could have a vector version of nnbathy?
>
> Carlos
>
>
> http://www.igc.usp.br/pessoais/guano/temp/lidar_bspline.jpg
>
> http://www.igc.usp.br/pessoais/guano/temp/lidar_nnbathy.jpg


The ugly things in the outer regions are due to the interpolation  
method. I can do nothing. The other artifacts correspond to a badly  
overlapping between regions. I have more "homeworks" than I expected :-S

I beg your pardon for all these problems and errors. Although the old  
bspline versions worked nicely, the grass6.x version is quite young  
(it is available since the end of July) because I rewrote almost  
everything except the interpolation functions. In the other hand, it  
was not really tested till now, just when you all began to use it. I  
know, those are not valid excuses, sorry.

Regards,
Roberto.