Dennis,
You wrote:
>> Does anyone know the mathematical parameters of the HPGN datum?
>> I have a large amount of data in shape file format that I'd like to
>> import into MapInfo using the Universal Translator. Unfortunately, the
>> coordinate system of the shape files uses the HPGN datum, which as far
>> as I can tell isn't included in MapInfo's prj file. If I had the
>> ellipsoid and shift parameters I could define a custom datum and
>> coordinate system for HPGN, and import the files.
HPGN (High Precision Geodetic Network) datums are 'enhanced' or 'readjusted' NAD83
datums. Unfortunately you can't simply define an ellipsoid and shift parameters for a
HPGN based datum. The NADCON method with associated latitude and longitude grid shift
files are required in order to convert to and from HPGN based datums. As far as we
can tell from the documentation, HPGN datum transformations are not supported within
MapInfo at this time.
You might want to check out our Geographic Calculator application at
http://www.bluemarblegeo.com/appcalc.htm
The Geographic Calculator fully supports HPGN transformations of
Shape/Tab/AutoCAD/etc. map file formats, among it's other features.
Thanks,
Jeff Cole
[EMAIL PROTECTED]
Blue Marble Geographics
"The Geographic Software Component Company."
www.bluemarblegeo.com
261 Water Street, Gardiner, Maine 04345 USA
Voice: 207-582-6747 Fax: 207-582-7001
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