Coordinate Transformation wizard page enables feature geometry re-projection from drawing coordinate system to resulting data file's coordinate system:

Export Features wizard Coordinate Transformation page

This wizard page provides following options:

• Flatten feature geometry to 2D - if checked, forces exported feature geometry to 2D.
• Disable feature coordinate transformation - If checked, disables feature coordinate transformation.
• Source spatial reference system - represents default coordinate system of the current drawing (if any).
• Target spatial reference system - represents coordinate system of the resulting data file.

It also provides following navigation buttons:

• Previous - returns to Specifying Resulting Data File wizard page.
• Next - proceeds to Specifying Feature Filter wizard page.
• Cancel - exits this wizard and closes the dialog.
• Help - displays this help page.

Specifying Spatial Reference System

Spatial reference system (SRS) or coordinate reference system (CRS) is a coordinate-based local, regional or global system used to locate geographical entities. A spatial reference system defines a specific map projection, as well as transformations between different spatial reference systems. If coordinate transformation is not disabled, it is possible to set both source (current drawing's) and target (resulting data file's) coordinate systems, thus providing parameters for feature geometry coordinate transformation.

Feature Export wizard enables changing both source and target spatial reference system by clicking on button next to the source spatial reference system name:

Coordinate Reference System dialog