Find a free clean image of the area you wish to build the map for.

Trace the outlines of the areas on the map using illustrator or Inkscape

Try to run a simplify paths command to reduce the number of points on the traced paths

For my map, I chose a dimension of 450 x 850mm, scale the image to the size you want for your map

extrude all closed contours on the image. by 4mm (acrylic sheet thickness)

Create an offset between all the cells on the map, this ensures that the map has a standard clearance throughout the build. (0.2mm is good)

The map can be made with all the cells on one plane, or you can choose to raise some areas on the map as I did for my mine, to give the map a little dimension, flat will be easier

The 3d printed edge holder is mostly structural, it provides a way to secure the cell to the back acrylic panel, holds the led strip right against the edges of the map cells,  and also partially obscures the harsh light from those edges.

Add holes for 3d printed studs, if the map area is large.

The name feature on the map cells should be inverted so it shows up normally from the front but modeled on the back side.