[GRASS-user] lidar data - nnbathy x bspline

[Roberto Antolin]

Hi Carlos and all,

> Ciao Roberto.
>
> Nice work with v.surf.bspline! I ran some tests, this time no
> artifacts were produced in the sub-regions limits. Alsdo it is very
> fast!
>
> I'd just like to poin some issues:
>
> - You could add, in the output messages, a indication of how many
> sub-regions will be used, so the user knows approximately how much of
> the interpolation has been done, how much still left.

Yes, you are right! I've already thought it. I'll see what I can do.
Just a question, what do you think about the output messages? Are they a 
lot or are they usefull?

> - I tried to use the --overwrite option, but it didn't work.
>
> - I did a test on an area 3.2x0.9 km, with 1m resolution, and it
> worked fine. When I changed the resolution to 0.25m, I got an error
> msg:
>
>> GRASS_INFO_ERROR(12405,3): Interpolation: The region resolution is
>
> too high: 46080000.000000 cells. Consider to change it.

Due to allocation memory problems I have to constrain the number of 
total cell.
I have to try to resolve this. Anyway, do you really need a 3km^2 DTM 
with such a resolution? ;)

> It worked with a resolution of 0.33m, but the resultant surface were
> with a "pixelated" look, I don't know if is a problem with bspline or
> GRASS dealing with non-round values for UTM regions.

Could you give us a link as you did with bspline.jpg and nnbathy.jpg, 
please?

> That's all for now. If I find anything more, I'll let you know

That was a lot! Thank you very much for your help!!

>> > http://www.igc.usp.br/pessoais/guano/temp/lidar_bspline.jpg
>> >
>> > http://www.igc.usp.br/pessoais/guano/temp/lidar_nnbathy.jpg 
>
Another last question, are these immages above the commands output maps 
or are they aspect raster maps?

Regards,
Roberto.

-- 
Roberto Antolín Sánchez
Politecnico di Milano – Polo Regionale di Como
(Laboratorio di Geomatica V2.8)
Via Valleggio, 11 – 22100 Como, Italy
tel: +39 031 332 7533 || fax: +39 031 332 7519 
email: roberto.antolin at polimi.it