[Liblas-devel] estimating lines and samples

[David Burken]

Thanks Hamish I'll check that out.
Dave


On 02/08/2011 10:31 PM, Hamish wrote:
>>>> I'm writing a plugin for ossim to form an image
>> from las files.  This will be open sourced as soon as
>> it's useful.  Does anyone have any advise on how to
>> choose a grid resolution which will determine the lines and
>> samples?  I thought about using the square root of the
>> number of points for a return and then scaling by ratio of
>> the bounding box.  It would be nice to pick a grid size
>> that gets at least one point for grid.  Any ideas?
>
> it will be hard to beat GRASS GIS's r.in.xyz module!
>
> As the author of it I'm totally biased of course, but it's true.
> :-)
>
> the only thing it doesn't do is multi-threading, but as it's
> I/O limited (and blindingly fast) that's not really an issue.
> Input filesize is only limited by operating/file system, or
> no limit if piping from stdin. tested with 300+ GB input file
> by the US Fish&  Wildlife Service, only took it some hours to
> churn through.
>
> Massimo Di Stefano should be able to give you some tips on
> smooth ossim+grass workflow/cooperation.
>
>
> see http://grass.osgeo.org/wiki/LIDAR for tips on first creating
> a "n" grid map, and then after clearing out the n=0 cells, using
> univariate statistics on the rest to decide on your grid
> resolution/density.
>
> I'm stongly in favour of forcing the user to set the grid size
> manually [ie thinking about it], but then I'm more concerned
> about the data product than fast visuals.
>
>
> regards,
> Hamish
>
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