# Projection Types - MapInfo_Pro - 2023

## MapInfo Pro Help

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MapInfo Pro Help
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2023-09-12
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2023-09-12T16:39:16.995549

The projection type is the equation or equations used by a coordinate system. For a list of projections MapInfo Pro uses, see Projection Types List.

## Specifying the Bounds for Coordinate Systems

You can specify the bounds for coordinate systems in the MapInfo Pro .PRJ file. To do so, add 2000 to the projection number and list the bounds after the projection parameters. The general form is:

``name, projectionnum + 2000, projection parameters, x1, y1, x2, y2``

For example, to define a UTM Zone 10 coordinate system with bounds of (100000, 400000) to (200000, 450000), use this line:

``````"UTM Zone 10", 2008, 74, 7, -123, 0, 0.9996, 500000, 0, 100000, 400000,
200000, 450000``````

To define a Longitude / Latitude coordinate system with bounds of (-50, 30) to (-48, 35), use this line:

``"Longitude / Latitude", 2000, 0, -50, 30, -48, 35``

You can also define a coordinate system with bounds and an affine transformation. In that case, add 3000 to the projection number, and list the bounds after the affine transformation constants. The general form is:

``````name, projectionnum + 3000, projection parameters, unitnum, A, B, C, D,
E, F, x1, y1, x2, y2``````

## Accounting for Affine Transformations and Explicit Bounds in Projection Types

You can modify projection type entries in the MAPINFOW.PRJ to add a constant value to account for affine transformations and explicit bounds. Valid constant values are listed in the next table:

Constant Coordinate System has: Parameters

1000

Affine transformations

Affine units specifier and coefficients appear after the regular parameters for the system.

2000

Explicit bounds

Bounds appear after the regular parameters for the system.

3000

Both affine transformations and bounds

Example:

In this example we use the Transverse Mercator coordinate system with the NAD 1983 datum. You might have this line in your MAPINFOW.PRJ file:

``"UTM Zone 1 (NAD 83)", 8, 74, 7, -177, 0, 0.9996, 500000, 0``

If you want to account for an affine transformation for this system, you would add the constant to the projection type and append the parameters of the affine transformation as listed below:

Units=meters; A=0.5; B=-0.866; C=0; D=0.866; E=0.5; and F=0

Therefore, the new entry to append the parameters of the affine transformation would be:

``````"UTM Zone 1 (NAD 83) - rotated 60 degrees", 1008, 74, 7, -177, 0,
0.9996, 500000, 0, 7, 0.5, -0.866, 0, 0.866, 0.5, 0``````

where:

Entry Description

1008

Achieved by adding the constant (1000) to the projection type (8)

7

Units for the affine transformation (7 = meters)

0.5, -0.866, 0, 0.866, 0.5, 0

Affine parameters. See Understanding Affine Transformations.

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:

Entry Description

2008

Produced by adding the constant (2000) to the projection type (8)

-500000, 0, 500000, 1000000

Explicit bounds parameters

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:

Entry Description

3008

Produced by adding the constant (3000) to the projection type (8)

7

Units for the affine transformation (7 = meters)

0.5, -0.866, 0, 0.866, 0.5, 0

Affine parameters

-500000, 0, 500000, 1000000

Explicit bounds parameters (See Accounting for Affine Transformations and Explicit Bounds in Projection Types.)

Note: For more about affine transformations, see Understanding Affine Transformations.