[GRASS-dev] Re: [STATSGRASS] r.in.xyz: New module for loading and binning massive x, y, z datasets (LIDAR, Swath bathymetry)

[Thomas Adams]

Hamish,

I think this is a wonderful and much needed addition. Thank you very much!

Regards,
Tom


Hamish wrote:
> Hi,
>
> In blatant violation of any sort of feature freeze for the next release
> of GRASS GIS I have added a new (long missing) module to GRASS 6.1:
>   r.in.xyz
>
> This is a replacement for s.in.ascii+ s.cellstats+ s.to.rast in GRASS 5.
>
>
> The r.in.xyz module will load and bin ungridded x,y,z ASCII data into a
> new raster map. The user may choose from a variety of statistical
> methods in creating the new raster.
>
> r.in.xyz is designed for processing massive point cloud datasets, for
> example raw LIDAR or sidescan sonar swath data. 
>
> And it's fast. Very fast.
>
>
> idea:
>   http://grass.itc.it/pipermail/grass-dev/2006-May/023376.html
>
> help page:
>   http://grass.ibiblio.org/grass61/manuals/html61_user/r.in.xyz.html
>
> screenshots:
>   http://hamish.bowman.googlepages.com/grassfiles#xyz
>
>
>
> The r.to.vect module has been given a "-b" flag to skip building vector
> topology (same as v.in.ascii) and the v.surf.rst interpolation module
> has been modified to not require topology from input points. This gets
> around the approx 3 million point memory limit of the vector engine due
> to topology overhead. [i.e. you can fill holes with regularized splines]
>
>
> question for stats experts: Should it be using population or sample
> variance? n is generally low so it makes a difference here. In r.univar
> it is usually so large not to matter (there we use population variance
> for vague reasons).
>
>
> Thanks to Helena Mitasova for testing and helping me work out the last
> few bugs. I would be interested to hear how things go with Large input
> files (LFS, bigger than 2gb).
>
>
> enjoy,
> Hamish
>
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>   


-- 
Thomas E Adams
National Weather Service
Ohio River Forecast Center
1901 South State Route 134
Wilmington, OH 45177

EMAIL:	thomas.adams at noaa.gov

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