Datum Transformations from las2las?

[gmcw49...@gmail.com]

Are Datum Transformations now available in las2las?
Would like to go from NAD83 to NAD83 HARN for Washington State ....
Thanks!
Guy

[Martin Isenburg]

Hello,

sorry. You can change the EPSG code from NAD 83 to NAD 83 HARN but the coordinates will not actually be re-projected by las2las from LAStools in the current implementation, but if there is an easy formula we could add this. Also see Kirk's blog from NOAA CSC at

http://geozoneblog.wordpress.com/2015/12/31/nad83-realizations-and-georeferencing-lidar/

if it is even worthwhile considering.

Regards,

Martin

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[gmcw49...@gmail.com]

According to my co-worker, the difference between coordinates in NAD83 vs NAD83 HARN can be up to 4 feet in Washington State.
Might not make much of a difference to 3 foot DEM, but could be significant to the point cloud ...

I have no idea how simple the formula are, but I can not imagine they are simple ...

Guy

[Kirk Waters - NOAA Federal]

The shift from NAD83(86) to NAD83(HARN) can be done with the NGS NADCON program (http://www.ngs.noaa.gov/TOOLS/Nadcon/Nadcon.shtml). However, it doesn't know anything about LAS. Underlying the tool are grids with the shift for different areas (grids are by state if I recall correctly). Interpolating those grids gives the shift in lat lon at a given lat lon. 

There are also a couple programs (geocon and geocon11) out there for the shift in NAD83 realizations from HARN to NSRS2007 and from NSRS2007 to 2011. I haven't looked to the underlying grids for those, but I expect the shifts to be fairly small. That might not be true in areas of rapid plate movement such as Southern California and I should probably go take a look.

Kirk Waters, PhD                     | NOAA Office for Coastal Management

Applied Sciences Program      | 2234 South Hobson Ave
843-740-1227                          | Charleston, SC 29405    

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