2D transformation of DTM file

This function is useful for transforming coordinates from one coordinate system to another. It is also useful where survey data has been entered using an incorrect backsight. In that situation,you can correct the data by transforming the coordinate system onto the backsight that was used.

To run this function: Choose File tools > Transformations > 2D transformation of DTM file, or Surfaces > DTM file functions > 2D transformation of DTM file, or Solids > Solids tools > 2D transformation of DTM file, or...

• In the Function Chooser, type 2D TRANSFORM DTM, and press ENTER.

Fields on the Transform coordinates of DTM (2d) form

Field	Description
Define files to transform
Location	The file or files you are transforming.
ID range	The ID numbers of the files you are transforming.
Define files to create
Location	The name and location of the output string file or files. This might be the same or different to the input files defined in Location and ID range above.
Any Z correction	Selected: Allows you to alter the Z values as well as the X and Y coordinates. Cleared: Allows you to alter only the X and Y coordinates.
Transform AB axis	Selected: Transforms the axis. Selected: Does not transform the axis.
(A)ddition or (M)ultiplication	Addition: The Z correction is added to the current Z values. Multiplication: The Z correction is multiplied by the current Z values. Note: This is only applicable if you selected Any Z correction.
Correction factor	The constant that is added to or multiplied by the Z values. Note: This is only applicable if you selected Any Z correction.
Define transformation parameters
Old points	The coordinates of two points in the old coordinate system.
New points	The coordinates of the same two points in the new coordinate system.

After you have completed the Transform coordinates of DTM (2D) form, the Verify transformation parameters form displays the following parameters, which allows you to verify that the transformation will produce the expected results.

Fields on the Verify transformation parameters form

Field	Description
Scale	The scale is determined by dividing the distance between the two new points by the distance between the two old points. Thus a scale of 1.0 means no stretching of the data. A scale value less than 1.0 means the data will become smaller. A scale value greater than 1.0 means the data will become larger, that is, it will cover a greater extent in the X and Y directions. The scaling is applied equally in both the X and Y directions.
Rotation	The clockwise angle through which the data is rotated from the orientation of the line between the two old points to the orientation of the line between the two new points. Note: The rotation is displayed in DDD.MMSS format if you have selected DEGREES as your Angle units, otherwise the rotation is displayed in GRADS.
Shift Y	This is the displacement in the Y values from old point one to new point one.
Shift X	This is the displacement in the X values from old point one to new point one.

Result

The new files are created with the data transformed in the way that you specified.