Postscript can fill areas bound by such lines if they form a closed path. The original map-lines in the .wdb files are not closed loops. I would need to decide on a colour scheme and a method of implementing it, if there was sufficient interest. Except for simple paths like state borders, most continents etc are made up of more that 1500 points. This is because of the different conventions used for RGB on a display and a printer.
Printers are linear devices.
A display doesn't absorb or reflect anything. We've assumed that the output is to a display. Now change the scale by a factor of 2, then make 4 maps. Some of you ask me. The package consists of a set of files which when sent to a Postscript printer will produce a map of your choice.