The map itself is scribed on real parchment from Pergamena, one of the few companies still producing the real thing.
Mr. Bigford was kind enough to share his technique for creating those nifty wax seals:
Go to a trophy place or any place that does laser engraving (wood plaques etc) bring them in the image (better to email them a digital one they can manipulate) and bring them in a piece of THICK plexiglass.
They can engrave plexiglass as easily as wood. BE SURE to tell them you want the image REVERSED ( the PICTURE cut IN and the outlines and BORDERS left RAISED) for a wax seal.
Once it's done cut them out (I recommend a bandsaw then a table top disk sander). Then glue (GORILLA GLUE) a "stamp handle" of some sort to the back.
NOW: It's TRICKY to make the seals. Plexiglass does NOT let go of the wax as easily as metal. Pour the wax onto a pane of glass, let it cool a bit (this takes practice to gauge) then press in the seal and LEAVE IT until the wax is totally cool (I place it in the fridge, it shrinks the wax and plexiglass, makes them harder and allows them to separate easier).
It's COMMON for the seal to not want to let go. You can experiment with breathing condensation onto the seal first, using water or a THIN coat of oil. The wax will be vacuumed to the glass. Start working the seal off slowly (NOT EASY) then razor blade the seal off the glass.
If the wax tears or will not come out of the seal properly (the smaller/more intricate the design the harder it is to release from all the nooks and crannies) Run it under VERY hot (you may have to boil some then pour it over it slowly) water and it will melt out the wax/clean the seal out. Then TRY TRY AGAIN!
After that drip some of the hot wax on whatever you want then lay the seal into it to attach it.
With the engraving: the SHALLOWER the image is cut the EASIER it is to make and remove the stamp!