Black diagonal stripes appearing on DSM after lasmerge and lasgrid

[beatric...@gmail.com]

Hello all,

I was wondering whether anyone had encountered the same problem with black stripes appearing on the created DSM (see image).
My workflow is the following using the LasTools Toolbox for ArcMap 10.2:
*) lasmerge to combine several .las tiles into 1 large contninuous .las file for my area of interest.
*) lasgrid with each cell of 1 sq unit filled with maximum elevation
I've checked my initial .las files as well as the merged .las file for anomalies but can not detect any.
The black stripes have pixel values of 0.

I would be grateful for any advice on how to avoid this from happening.
Thank you,
Beatrice Wedeux

[Terje Mathisen]

beatric...@gmail.com wrote:
> Hello all,
>
> I was wondering whether anyone had encountered the same problem with
> black stripes appearing on the created DSM (see image).
> My workflow is the following using the LasTools Toolbox for ArcMap 10.2:
> *) lasmerge to combine several .las tiles into 1 large contninuous
> .las file for my area of interest.

This is exactly as designed by Martin: You need to either limit yourself
to working with small data samples/tiles, or buy a full licence to his
product!

The black diagonals are there to give you an output which shows what you
can get, but which cannot be used professionally until you buy that license.

Terje

> *) lasgrid with each cell of 1 sq unit filled with maximum elevation
> I've checked my initial .las files as well as the merged .las file for
> anomalies but can not detect any.
> The black stripes have pixel values of 0.
>
> I would be grateful for any advice on how to avoid this from happening.
> Thank you,
> Beatrice Wedeux

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--
- <Terje.M...@tmsw.no>
"almost all programming can be viewed as an exercise in caching"

[Bernardino J. Buenaobra]

Hi Beatrice:

Have you considered lastile with a buffer size option in you pipeline? Recently DMI (Dr.Martin Isenburg) on his extensive stint in the Philippines for university partners for the national LiDAR project that there could be defects showing at the interfaces of each las data set with a simple lasmerge.
We use typically 50m buffers as option to lastile before we do the rest of the processes. Of course that include a lasmerge after these process and we can do so removing the buffer at the final process step. Can you send in your data and let me try them on - only if your allowed to of course.

Regards,
Berns B.
USC Phil-LiDAR Research Center
________________________________________
From: beatric...@gmail.com [beatric...@gmail.com]
Sent: Tuesday, February 17, 2015 10:59 PM
To: last...@googlegroups.com
Subject: [LAStools] Black diagonal stripes appearing on DSM after lasmerge and lasgrid

--
Download LAStools at
http://lastools.org
http://rapidlasso.com
Be social with LAStools at
http://facebook.com/LAStools
http://twitter.com/LAStools
http://linkedin.com/groups/LAStools-4408378
Manage your settings at
http://groups.google.com/group/lastools/subscribe

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