hi Ali,
There are a couple of ways to go about this. What I've done in the past is:
- Run las2txt on the LAS files
- Convert the ellipsoid heights to orthometric heights using VDatum. BTW- you can invoke a command line version of VDatum. The details and software are at:
http://vdatum.noaa.gov/docs/userguide_cmd.html
-Run txt2las on the output from VDatum
It's a little convoluted but if you know a little Python or a similar language
this can be done in pretty much one step.
Good luck!
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Today's Topics:
1. Re: las2txt question (Howard Butler)
2. Re: Re: las2txt question (Etienne Bellemare)
3. Vertical Datum Transformation (Ibraheem Ali)
----------------------------------------------------------------------
Message: 1
Date: Thu, 28 Oct 2010 15:22:29 -0500
From: Howard Butler <[email protected]>
Subject: [Liblas-devel] Re: las2txt question
To: Randy Bucciarelli <[email protected]>
Cc: "[email protected]" <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On Oct 28, 2010, at 3:16 PM, Randy Bucciarelli wrote:
Hi Howard,
Is there a way to format resulting precision of values from the output of
las2txt?
Or does 'las2txt' simply output the precision of the values how there were
initially stored when creating LAS files?
There isn't, but I agree there should be an option to set/override the precision of x/y/z values (independently) I have rewritten lasinfo and las2las using the new C++ API, and I think las2txt should also be rewritten as well. In summary output and other venues in those rewritten utilities, I have tried to respect the specified scale/precision of the dimension if it was set in the header.
Rewriting las2txt similarly to lasinfo and las2las is in my queue, but I probably won't get to it for a bit.
Howard
PS, this question should be asked on the list, and I have forwarded it there.
------------------------------
Message: 2
Date: Thu, 28 Oct 2010 16:44:53 -0400
From: Etienne Bellemare <[email protected]>
Subject: Re: [Liblas-devel] Re: las2txt question
To: "[email protected]" <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Good point, I'd like to suggest also the ability to specify the header
separated the same way the fields are going to be. It will create a much
more consistent file. e.g. for the moment you can't use tab to seperate
header even if your fields are. Having the ability to set a name for the
header could be a nice feature too.
Thanks again,
Etienne
On Thu, Oct 28, 2010 at 4:22 PM, Howard Butler <[email protected]> wrote:
On Oct 28, 2010, at 3:16 PM, Randy Bucciarelli wrote:
Hi Howard,
Is there a way to format resulting precision of values from the output of
las2txt?
Or does 'las2txt' simply output the precision of the values how there
were initially stored when creating LAS files?
There isn't, but I agree there should be an option to set/override the
precision of x/y/z values (independently) I have rewritten lasinfo and
las2las using the new C++ API, and I think las2txt should also be rewritten
as well. In summary output and other venues in those rewritten utilities, I
have tried to respect the specified scale/precision of the dimension if it
was set in the header.
Rewriting las2txt similarly to lasinfo and las2las is in my queue, but I
probably won't get to it for a bit.
Howard
PS, this question should be asked on the list, and I have forwarded it
there._______________________________________________
Liblas-devel mailing list
[email protected]
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Message: 3
Date: Fri, 29 Oct 2010 09:21:36 -0600
From: Ibraheem Ali <[email protected]>
Subject: [Liblas-devel] Vertical Datum Transformation
To: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Dear All,
I'm a bit fresh with all LiDAR data processing and analysis.
I've got recently a bunch of LiDAR "las" format files, and their Vertical
datum is ellipsoidal "WGS 84". The vertical datum is not defined within the
las files, it was givin to me as a fact from the vendor.
I need to convert these files to NAVD88 Vertical Datum, and I basically need
to perform the following steps:
1- Define the vertical datum (WGS 84) ellipsoidal within the files
2- Transform to NAVD 88
I've got the "liblas" with "OSGeo w4", but I can not find a clear
descriptions to the datums available or sample code regarding the above
mentioned issue
I would ask you kindly to help me with this, and would you please direct me
to the right documentations?
Thank you very much
Ali
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