[OSRS-PROJ] Datum Shifts

[Alexander Weidauer]

Hi Folks,

I've implemented the code for the nad2bin tool but I can't find
the files

	 MD.lla
	 TN.lla
	 WI.lla
	 WO.lla
	 alaska.lla
	 hawaii.lla
	 prvi.lla
	 stgeorge.lla
	 stlrnc.lla
	 stpaul.lla    .

Now I ask how to integrate them.

Bye Alex
	

Frank Warmerdam schrieb:
> Folks,
> 
> I am working on implementation of NTv2 support, and as part of that effort
> I am trying to add a small test script for the existing datum support 
> ... try
> to make sure I don't break anything while improving things.
> 
> In doing so, I have started looking at the files for datum shifting and
> realized I am confused about them.
> 
> The files conus.lla, alaska.lla, hawaii.lla, prvi.lla, stgeorge.lla,
> stlrnc.lla, and stpaul.lla are all apparently files with grid shifts from
> NAD27 to NAD83, right?
> 
> The files FL.lla, MD.lla, TN.lla, WI.lla and WD.lla are listed in the
> README as being for "high precision conversion of geographic coordinates
> from NAD83 to NAD83".  What does that mean?  I presume this relates to
> HPGN, which I gather is a higher precision form of NAD83, is that right?
> Do these files shift from "old NAD83" to "HPGN NAD83" or the other way?
> 
> Best regards,
> 


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