Borderlands The Pre-Sequel

To unlock this achievement you will need to uncover all of the greyed areas of the map in Serenity's Waste, Triton Flats and Stanton's Liver. You will know when you have discovered an area as it's name will appear on screen telling you that you have discovered it. There are some secret areas that you are unlikely to happen across. 

In Serenity's Waste there is a secret boss lair. If you leave Janey Springs building via the vehicle door and hug the right hand wall you will be able to jump onto the roof. Walk along here until you see a lava-fall and jump onto the rocks at the top of the lava-fall. Go into this tunnel area to find a hole in the ground that you can drop down. As soon as you drop down you will discover the area. There is a level 30 boss here so be sure to be a high enough level to kill it, otherwise just drop down to discover the area, then let it kill you to get out quickly.

In Stanton's Liver there is a secret area that leads to a few more. If you travel to the back of the map where there is a railway line and head into the cave at one end of said line you'll find on the left hand side of the cave there is a hole in the wall that you will need to boost jump into. Once in here you will discover the area, then you will need to walk into the glowing purple slab in the middle of the area. This will teleport you to somewhere else where you will again find another glowing purple slab. Keep walking into these until you return to the original area.

Just grab a vehicle and completely uncover the map of these 3 areas and the achievement is yours.

This achievement is self explanatory. You must discover every named location in the listed areas, THIS DOES NOT MEAN JUST UNCOVERING THE MAP. Some locations you might not think to look:

• In Serenity's Waste, go up the stairs to the left of where you spawn. Follow them outside. Then, once you are outside, look to your right and jump onto the oxygen patch right there. Then there should be a long piece of metal in front of you, so jump on it and follow it all the way. Then, when you see another piece of mountain to jump on, proceed to do so. Then jump into the lava cave and land on the rocks located at the top of the lava-fall. Then jump down the hole to find the location.
• In Stanton's Liver, run through the map until you get to the bridge. There is a cave connected to this bridge. Go into it and keep left until you see an opening that you can jump into. Platform into it, and then follow it to the end. A location should pop when you follow the cave to end.
• In Stanton's Liver, follow the route described in the last bullet point. When you get to the end, the location called "Higgin's Gully". On the floor in front of you, you should see a bright purple pillar in the middle of the room. Walk into it to be transported to another location (this is personally what I was missing for the achievement).
• In Triton Flats, look at your map and search for the map exit to Vorago Solitude. There is a location right in front of that map exit, which is easy to gloss over.

I recommend going for these achievements after you complete all the side missions, as some locations are inaccessible until you complete certain side missions.