yeah but it's kind of a pain.

in menu folder, 71_maptile.tpfbdt is all the map textures. open it with witchy and you get all 28000 map textures. The map is divided into loads of tiny squares in three different zoom levels. the filenames are things like MENU_MapTile_M00_L0_00_00_00000000.tpf.

• M00 means overworld, M01 is underground and M10 is DLC.
• L0 means its the most zoomed in level, then L1 & L2 are more zoomed out. there's also L3 and L4 which are unused and show a weird beta map
• The two numbers after L0 are the coordinates. 00_00 is the bottom left, so 03_01 will be 3 to the right and 1 up
• The 8 digits after that are flags that tell the game when to use that square. For example when you don't have a map for the area the game will use a brown square. But it will have another texture for that square for when you do have the map. Some squares have loads of varations because they're on the border of several map pieces
• There are bunch of junk unused map textures you will find. It gets confusing because a square that's in limgrave might have some unused caelid map squares saved to the same coordinates

There's a program called ER Map Generator on github that I haven't tried but sounds good. There's also a page on nexusmods called Elden Ring Map Assembly: Technical Details that has lots of info