Of course your coordinate will be different from one datum to another (only Nad83 and WGS 84 are basically the same). Datum is a spheroid to represent best the earth for the region in which you are. If the spheroid parameters change, the "earth also changes".
Read page 440 of the 6.0 User Guide (chap 28). you can also read Chap 27.
Regards,
Jean-Yves
At 11:50 2001-11-21 -0800, you wrote:
G'day all
I just reprojected a batch of GeoTiffs (USGS DOQQs) from Nad83 to Nad27 using the Batch reprojection wizard from ERM. I have noticed that the same point on the photo now longer has the same Lat and Long in the 2 projections (the UTM coordinates for the same points are different, but that is mean't to be the case I believe - ?). I used a bilinear resampling method for the reprojection, but the same thing happened if I used the nearest neighbour method.
The point in Nad83 has UTM coordinates (zone11) 561392.93E / 4544597.60N; 41:3:7.94N / 116:16:10.06W
The same point in Nad27 is 561314.00E / 4544799.00N; 41:3:7.62N / 116:16:13.37W
Is this sort of variation in Lat and Long normal?
Thanks in advance
Cheers
Ken Hickey
------------------------------------------------------------------
Dr Kenneth Hickey
Mineral Deposit Research Unit (MDRU)
Department of Earth and Ocean Sciences
University of British Columbia
6339 Stores Rd, Vancouver, BC V6T 1Z4, Canada
phone +1-604-822-3765; Fax +1-604-822-6088
email: [EMAIL PROTECTED]
.
Jean-Yves Lauture
Geomatics Representative
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