there are 5 different locations within this DLC. just walk around each area to uncover the map. you should get most of the map done just by doing all of the side missions for this DLC
Hunters Grotto
Hammerlock's Camp
Lodge
Ardorton Station
Bone Metal Camp
The Psycho Surgery
The Morgue
The Ardo Farm
The Skin-Chop Chop-Shop
The Offal Overlook
Iron Rail Rotunda
The Infernal Machine
Scylla's Grove
The Sun Swamps
Root Hill Village
The Ardorton Docks
Grifters Reak
Roothill Village
Low Gut Rut
Dropwater Cavern
Candlerakk's Crag
Elite's Crossing
Lower Bluff
The Rage Cage
The Big Bluff
H.S.S. Terminus
Sunken Cargo Room
Nakayama's Laboratory