I have made a blank map of the Great Sothern Island. Part of the Harda Archipelago, is the island where Semer Republic and Aŭstrasuno Tero are.
I made it first downloading all the coastline data from OGF in JOSM, there was a need to filer it using the search options in JOSM (natural=coastline selected). All those filtered data, which should be the coastline and the administrative borders, where copied and pasted in the same position into a new layer in JOSM, then I exported it to a .gpx file. Using the aplication gpx2svg I converted the .gpx file to a .svg one. Once converted, I used Inkscape to read the .svg and then exporting the final draw to a .png file. This was made using Linux, I don't know if there is a way to do it in Windows or Mac, but there should be (if not, try Linux, it is free :D !).
This is a blank map, it is an example of how to get blank maps easily.