Pitney Bowes MapXtreme - Manual (Page 586)

Appendix H: Elements of a Coordinate System
National Transformation v. 2 (NTv2)
MapXtreme v7.1 593 Developer Guide
WGS 84 minus local datum LD-3
This datum uses the Clarke 1880 ellipsoid, which is number 6 in the ellipsoid table above. We do not
need to reverse the signs of the parameters or worry about the order of the rotation parameters
(since they aren’t present). In this case, you can use datum number 999 instead of 9999 in the
custom datum definition. These two definitions are equivalent, and you can use either one:
999, 6, -7, 36, 225
9999, 6, -7, 36, 225, 0, 0, 0, 0, 0
As with the other custom datum definitions, you would insert one of these definitions in place of the
datum number in a MapInfoCoordinateSystemSet.xml line, as follows:
"Longitude / Latitude (LD-3)", 1, 999, 6, -7, 36, 225
<srsName>UTM Zone 30 (LD-3)</srsName>
- <srsID>
<code>coordsys 8, 999, 6, -7, 36, 225, 7, -3, 0, 0.9996, 500000, 0
</code>
<codeSpace>mapinfo</codeSpace>
<remarks>Universal Transverse Mercator (LD-3)</remarks>
</srsID>
National Transformation v. 2 (NTv2)
The National Transformation v. 2 (NTv2) algorithm and grid shift file format, developed by the
Geodetic Survey Division of Geomatics Canada, enables you to convert data from the NAD 27
reference system to the NAD 84 reference system. Grid shift files used with the algorithm contain
one or more rectangular grids that indicate the coordinate differences between NAD 27 and NAD 83.
The National Transformation was originally designed to convert Canadian data from NAD 27 to NAD
84. This format was later adopted for datum conversion in Australia, New Zealand, and Germany.
The NT v. 2 algorithm has been implemented in MapXtreme 6.7.1 to support these transformations
Grid shift files have also been added for the following countries:
• Canada
• Australia
a 6378249.145 m
f 1 / 293.465
dX -7 m
dY 36 m
dZ 225 m