JEDMICS C4

Overview
JEDMICS C4 is a raster image file format.

The name comes from an entity named JEDMICS (Joint Engineering Data Management Information and Control System), which is related in some way to the U.S. Department of Defense.

Specifications

 * https://www.jedmics.net/public/C4-Img-Spec.pdf (SSL certificate problems as of 3/2013, but no alternate source could be located)

Software

 * XnView