Geographic Coordinate Systems Transformation

Use the Geographic Coordinate Systems Transformation dialog to specify a datum transformation when adding an ArcGIS LYR, LYRX, or SHP file to the Data view of a map that uses a different datum.

Geographic Coordinate Systems Transformation dialog options

The table lists the data sources currently being added to the Data view that use datums differing from the view's datum.

Data Source	Datum
The name of the input file.	The name of its datum (or the name of the GCS in the case of LYR data).

Convert from

Select the datum (or GCS in the case of LYR data) for which you want to specify a datum transformation.

Into

The datum (or GCS in the case of LYR data) used by the Data view is displayed.

Local Datum Transform

Select the datum transformation you want to use from the drop-down list:

Geosoft names

The Geosoft names option is selected by default for SHP data. The list of available transformations will contain the Geosoft defined ones, which expose the recommended Area of Use.

ESRI names

The ESRI names option is selected by default for LYR data. The list of transformations will contain the Esri defined ones, which do not expose an Area of Use.

View ESRI's geographic transformation PDF online

Click the link to launch the PDF containing descriptions of the Esri Geographic (datum) transformations, parameters, and areas of use.

Selected datum transformation parameters:

Translation (dX, dY, dZ)	If the local datum transform has a translation in the X, Y, and Z, the corresponding dX, dY, and dZ translations are displayed (in metres).
Rotation (Rx, Ry, Rz)	If the local datum transform has an additional rotation applied, the corresponding Rx, Ry, and Rz rotational angles are displayed (in arc-seconds).
Scale	The scale difference, specified in parts per million (ppm).