File:DeePsea session.png

Summary
Typical mapping activity in DeePsea (version 12.15.3 under Windows XP), linedef mode. The large gray window is the editing interface where linedef and sidedef properties may be changed. The black area is the overhead map view, below which pops up summary data about the linedef nearest the mouse pointer. Analogous arrangements are seen in sector, thing, and vertex modes.