From the backstage, selecting the Information item will display the Information panel from which you can get information about the current file and to compress the file.

General

The General section displays different information about the file.

Compact File

The Compact File button compresses the file size.

Coordinate System

The Coordinate System button assigns the coordinate system for the file. The list includes common generic universal coordinate systems as well as local and state plane coordinate systems within the project location.

Terrain Sources

The Terrain Sources button launches a panel displaying the origin of the terrain model attached to the file.

Save Location

The Save Location button saves the polygon edits after it has been placed and then modified.

Reset Location

The Reset Location button resets or cancels an edit to the project location polygon.

Vertical Datum

With an existing terrain file (3sm), you have the ability to change the vertical datum of the terrain.