To get these maps...just mine, or botany (not sure about fishing) lvl 50 nodes...(I am sure you can do this with lower level nodes...but why?)

First time I tried...I got it a Boarskin on my first try (mor dhona).... Second try I wanted to grab a Piesteskin to do with my FC...took about 10 minutes of mining and not hitting a few single player maps. (Northern Thanalan---Cobalt Ore area)

Now once you get a map... it will tell you that you need to decipher!

To Decipher, you will need to go on a quest line. This quest line starts in Eastern La Nos, right outside the area that most people would fix their gear before or during Coil in Wineport.

After you complete this simple quest line...you have the ability to Decipher and Dig. (these will be in your normal abilities tab on the menu)

Decipher the Map...UNDERSTAND THIS. The Map is a ZOOMED IN version of the map that the treasure is on. Just look at it and compare it to the main map to determine where the treasure is.