[Proj] How to transform between NAD83 HARN/HPGN and WGS84

Clifford J Mugnier cjmce at lsu.edu
Thu Feb 19 13:24:35 EST 2009

Mr. Friesen:
Such questions regarding geodetic-accuracy transformations in Colorado are best directed to the U.S. National Geodetic Survey.  NADCON indeed does have NAD83 HARNHPGN files, and can provide the necessary operations either on-line or through a download.  The same goes for current versions of CorpsCon.  Both solutions are not commercial and both are free.
Go to www.NOAA.NGS.gov and you'll get your problem solved for free courtesy of the U.S. Government.  A Google search will get you to the current version of CorpsCon.
C. Mugnier


From: proj-bounces at lists.maptools.org on behalf of Aaron Friesen
Sent: Thu 19-Feb-09 11:20
To: proj at lists.maptools.org
Subject: [Proj] How to transform between NAD83 HARN/HPGN and WGS84


I checked the archives for the past year and did not find an
answer to this.  Google did not provide me with any leads

I have data in NAD83 HARN for Colorado.  I need to take the
data into the field as WGS84, update it/add to it, and get
it back as NAD83 HARN for Colorado.  The data I am collecting
has sub-foot accuracy, so "close" is not good enough.

The information on the grid files does not address the
HARN/HPGN question.

Is this type of transformation with the accuracy I need
possible with Proj?

Are HARN grid files available or are towgs84 settings defined
for the various HARN areas?

Or am I stuck looking for an alternative, commercial solution?

Thank for your assistance.


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