the map format was decrypted by PfhorSlayer a year ago. (May 20th, 2003). Since then, we've been able to decrypt the maps, and all the tags that make up the maps. luckily, Bungie 'told' us that the game had these things called tags, so we actually kinda knew what to look for. In August of last year, the project gained speed, and we were able to get more than 4 tanks into bloodgulch. PfhorSlayer announced in the IRC chat room on August 7th, 2003
"Holy mother of god.... I have 8 tanks in bloodgulch" (as far as I can remember that's what he said). No one believe him. We demanded a screenshot, or rather, a picture. Sure enough, after a few minutes, Pfhor had put up a digital camera picture of the eight tanks in BG. A day later, we had uncovered the flamethrower, and gravity rifle hidden in the map files. As time went on, we went through several different programs.
First, there was HaloMapExpander. This app led the way to finding the offsets of all the tags, and allowing us to 'see' into a map file, and view what the maps contained. The first version of HME only figured out small bits of information, and allowed us to decompress the maps from the halo dvd. (As the maps are compressed using zlib, a very popular compression scheme). The next few versions allowed recompression of edited maps, as well as extraction of all tag information, and other info. (Of which was the driving force behind future programs). Eventually, HME ended its life with a version that allowed model and texture extracting. AFAIK, the project was cancelled around the release of the next program, HaloMapTools.
HaloMapTools was originally created to hear the sound files and view the bitmaps inside the maps.
WinHME was/is a gui that I created for use with both HaloMapExpander, and the next program listed.
Around this time, KornKob released his revolutionary BanshInject program. The program allowed people to inject files into the maps, and by inject, I mean put in brand new files over old files.
Over time, HMT evolved into a universal map editing program. v2 was the most revolutionary version of its time, as it allowed bitmap editing, and injecting. Model injection was still a dream.
In november 2003, we managed to recieve the best version of HMT ever. v3. The app allowed "batch extract" and map rebuilding. From November untill (February?) March '04, we used v3 to modify the tags and bitmaps, and models in the map files, as well as extract all the tags from the map files, and swap parts of one map into other maps.
In March, v3.5 came out, and is still the best editor for xbox Halo map editing. What we need now is a modified tool.exe, which ships with the HEK, for use with xbox maps. If we can make such a tool, (pun not intended), we would be able to use the HEK for building our own xbox maps.
Until the next wave of programs for editing xbox maps comes out, I don't know what is in the future for us xbox users.
I hope this has educated you in the editing of maps, and how it all came to be.

jimmsta