How to export a comprehensive map to the web, with a few details left out in favor of getting to work on time:
Step 0: Make a copy of your save folder for backup
Step 1: Load Fortress
Step 2: Designate bottom level for mining
Step 3: Run Reveal.exe
Step 4: Under Options, Export Local Image
Step 5: Save Game and quit or Abandon the Fortress and quit or Crash the program with _the_ three fingered salute.
Step 6: Delete your save folder, replace with backup
Step 7: Use the Dwarf Fortress Map Compressor to compress the bitmaps created in step 4.
Step 8: Upload the map.
Alternately...
Step 1: Go to your save folder.
Step 2: Make a copy of your fortress' region, and give it the next available region.
Example: If you have region1, region2, region3, and your fortress is in region2, then make a copy of region3 named region4
Step 3: Open up Dwarf Fortress, load up the duplicate of your fortress, run reveal.exe.
Step 4: Save game
Step 5: Play in your original region (unreaveled), only loading the revealed copy when you want to consult.
As an aside, check out the Regional Prospector utility. I found that on the wiki recently. I don't like to reveal all the surprises, but there are occasions where I end up doing so for various reasons.