Thanks to Pendra at the STO forums for teaching me how to do this.  It’s a pretty simple trick, so I’ll just tell you about it, rather than recording a video about it. 

On interior maps, you can use “Building Block Platform #3” to cover the map screen, thus creating a “fog of war” effect where the enemies and other stuff are hidden from the map screen.  This also affects the minimap, although enemies still show as red dots.

The trick: Put the platforms in the ceiling.  If they are too high, the map will show, and if they are too low, the player might see them poking down through the ceiling. 

To replicate the above screenshot:

Map: Forging

Set Y coordinates of 3 platforms to 40, and use them to cover the map.

Thanks again to Pendra for sharing that with me at the STO forums.  I hope that it is useful to many of you out there.