There is only one file type that uses the .OVP extension:
The Overlay Maker Package File
File created by The Overlay Maker, a map drawing program designed for military planning; stores all map images and drawn objects in a compressed .ZIP archive (with the ".ovp" extension); used for packaging overlay graphics together with the map.
While working on an overlay, you can create an overlay package by selecting.
|The Overlay Maker||Free|
Updated: October 20, 2011