Geometric region markers can be placed on the screen interactively or via the XPA "regions" public access point. ... To define a data region (by default, an "Include in Source" region): . ... Move to the desired image location and click the left mouse button. ... Type "Ctrl-e" to change from "include data with region" to "exclude data within region". ... Closed markers (circles, ellipses, etc.) may be resized by clicking and dragging the left mouse button on the region perimeter. ...