[Liblas-devel] las2las vertical unit conversion

[Finnegan, David ERDC-CRREL-NH]

Be very careful converting vertical units. Especially when there is a
different datum or ellipsoid. Often, it's not a simple conversion from ft to
meters. I would run a test in corpscon first.

D 
David C Finnegan 
Research Physical Scientist 
CRREL 
--------- 
Message sent via my BlackBerry Wireless Device 


________________________________

From: liblas-devel-bounces at lists.osgeo.org
<liblas-devel-bounces at lists.osgeo.org> 
To: Howard Butler <hobu.inc at gmail.com> 
Cc: liblas-devel at lists.osgeo.org <liblas-devel at lists.osgeo.org> 
Sent: Mon Nov 01 22:52:59 2010
Subject: Re: [Liblas-devel] las2las vertical unit conversion 


Hello Everyone,
 
This process " converting vertical units from foot to meter and vise versa"
is very important and it is usually needed when comparing multiple LiDAR data
from different sources.
 
Example: " When studying erosion in certain area, we need to have LiDAR data
taken in different time epochs. These data, if you have them, are usually not
in the same measuring units". 
 
In my case, I have the elevation in one set of data in "US Survey feet" and
the other set is in "meter". For now, I'm thinking to do las2txt, then
convert the elevation value, then back to las file.
 
It would be really nice to have this process implemented in las2las.
 
Thank you very much,
 
Best regards,
 
Ibraheem


On Mon, Nov 1, 2010 at 8:14 PM, Howard Butler <hobu.inc at gmail.com> wrote:



	On Nov 1, 2010, at 4:10 PM, Brady Callahan wrote:
	
	> Is there a way to use las2las to convert or scale Z units? I just
used las2las to translate data from EPSG:26910 to EPSG:2992 and it worked
fantastic! It took less than 25% of the time that LP360 (GeoCue) does for the
same operation! However, my Z units (meters) still need to be converted to
international feet. Is that possible with las2las?
	
	I don't see any reason why we couldn't, but it is not possible just
now.
	
	What about:
	
	--point-translate "x*1.0 y*1.0 z*3.2808399"
	--point-translate "z+20"
	--point-translate "z-20"
	
	I'd be interested in hearing feedback on this before implementing for
1.6.0b2's las2las.  Look good?
	
	Howard
	
	_______________________________________________
	Liblas-devel mailing list
	Liblas-devel at lists.osgeo.org
	http://lists.osgeo.org/mailman/listinfo/liblas-devel
	


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/liblas-devel/attachments/20101102/3e7b2f06/attachment.html