[Liblas-devel] GPS Time and inverted height

[Martin Isenburg]

hi,

the las2las version from LAStools [*] can do both Q1 and Q2.

for Q1 you can set a gps-time of 0.0 for each point with

las2las -i lasformat0.las -o lasformat1.las  -point_type 1

or for LAS points with RGB values

las2las -i lasformat2.las -o lasformat3.las  -point_type 3

for Q2 you can invert the height with

las2las -i lidar.las -o lidar_inverted.las -scale_z -1.0

cheers,

martin @lastools

[*] http://www.cs.unc.edu/~isenburg/lastools

On Wed, Jun 15, 2011 at 6:18 AM, Howard Butler <hobu.inc at gmail.com> wrote:

> On Jun 15, 2011, at 4:33 AM, Julian Olszewski wrote:
>
> > Sorry for asking two questions within the same thread.
>
> No problem.
>
> > Q1: Is there any way to populate a las file with "fake" GPS Time.
>
> Not with libLAS at this time.  las2las can only do translation on XYZ
> values at this point.  You could do it yourself using the Python bindings
> and a little bit of scripting (it would be much slower, of course).
>
> > The software I use require GPS Time - it's mandatory otherwise I won't be
> able to load the data
>
> Which software is this?  It would seem that it could do the faking itself
> if it didn't find time values.
>
> > Q2: Can I invert the height or multiply by -1?
>
> See above.
>
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