GMS:Coordinate Transformation

Coordinate Transformation means changing the position (xyz coordinates) of data. There are two ways to access this feature:

• Edit | Coordinate Transformation menu command. Accessed this way the command will transform all data.
• Right-click on an object in the Project Explorer and select the Transform command. This transforms just the object clicked on.

Coordinate Transformation Wizard

Doing either of the above will bring up the Coordinate Transformation Wizard. There are two steps.

Step 1 - Choose the method of transformation

The two options are:

• Geographic system transformation. This option is used to transform from one coordinate system to another.
• Translate, rotate, scale. This performs a simple transformation to move, scale, or rotate data.

Step 2 - Choose transformation options

Geographic system transformation option

All data will be converted from the system on the left of the dialog to the system on the right.

"Convert From" System

The Convert From system defines the coordinate system the data is currently referenced to. When working from the Edit menu, this is the system GMS is working in and is dimmed by default because it is assumed the user has already specified this system. When working from the Project Explorer, this is the coordinate system of the selected entity and must be selected. A user may edit the current coordinate system by selecting the check box at the top of the dialog.

"Convert To" System

The Convert To system defines the system the user will be working in after the conversion. When the dialog is invoked from the Edit menu, this is selected by the user and all data is converted from the current system to this new system. When the dialog is invoked from the Project Explorer, the Convert To system is dimmed because this is assumed to be the system GMS is working in and all other data is already in this system. In the convert to section the use may select the horizontal and vertical system to be used after the conversion.

Restrictions

Some conversions are not allowed, such as converting between a NAD and non-NAD system. A warning is issued when conversions are not allowed.

Translate, rotate, scale option

If the Translate, rotate, scale option was selected in step one, step two lets the user chose to either translate, rotate or scale. GMS cannot do more than one transformation at a time – for example, it's not possible to translate and scale at the same time. If wanting to do both, perform the translation first, then perform the scale.

See Also

• Transform