Datums – Pitney Bowes MapInfo Professional User Manual
Page 399
To supply explicit bounds to the coordinate system (x1, y1, x2, y2)=(-500000, 0, 500000, 1000000), the
required line entries would be:
"UTM Zone 1 (NAD 83) - bounded",
2008, 74, 7, -177, 0, 0.9996, 500000,
0,
-500000, 0, 500000, 1000000
where:
Description
Entry
Produced by adding the constant (2000) to the
projection type (8)
2008
Explicit bounds parameters
-500000, 0, 500000, 1000000
To customize the coordinate system using both the affine transformation and explicit bounds, the entry
in the MAPINFOW.PRJ would be:
"UTM Zone 1 (NAD 83) - rotated and bounded", 3008, 74, 7, -177, 0,
0.9996, 500000, 0, 7, 0.5, -0.866, 0, 0.866, 0.5, 0, -500000, 0,
500000, 1000000
where:
Description
Entry
Produced by adding the constant (3000) to the
projection type (8)
3008
Units for the affine transformation (7 = meters)
7
Affine parameters
0.5, -0.866, 0, 0.866, 0.5, 0
Explicit bounds parameters (See
Affine Transformations and Explicit Bounds in
Projection Types
-500000, 0, 500000, 1000000
Datums
A datum is established by tying a reference ellipsoid to a particular point on the earth. The following
Datums table lists the details for each datum:
• The number used to identify the datum in the MAPINFOW.PRJ file.
• The datum's name
• The maps for which the datum is typically used
• The datum's reference ellipsoid
For a comprehensive list of supported projection datums, see
For a list of datum changes by version, see Coordinate System Enhancements by Version in the MapInfo
Professional Help.
To create a custom datum, see Defining Custom Datums in the Help System.
Converting Coordinates from One Datum to Another
When converting coordinates from one datum to another, MapInfo Professional has used the Molodensky
(3-parameter) and Bursa-Wolfe (7-parameter) methods. These are general-purpose methods that can
convert coordinates from any datum to any other datum.
After the NAD 83 datum was introduced, NOAA developed a program called NADCON, which stands
for North American Datum CONversion. This is a very specialized program that converts coordinates
only from NAD 27 to NAD 83 and vice versa. For this specialized task, it is much more accurate than
399
MapInfo Professional User Guide
Chapter 15: Working with Coordinate Systems and Projections