EdMap
From DoomWiki.org
EdMap is a DOS sector-based level editor written by Jeff Rabenhorst. Features include:
- Support for Doom, Doom II and Heretic
- Online help including a hyperlinked version of the Unofficial Doom Specs
- Shortcuts to allow fast mouse editing
- Supports texture/sprite WADs.
- Easy to switch NODES builder by means of editing a batch file (defaults to WARM)
- Expert mode that allows all map properties to be edited
Drawbacks of EdMap include a 640KB memory limit and some stability bugs - when using EdMap it is important to regularly save and keep backups of levels.