[Xastir] Creating own vector maps?

[Tapio Sokura]

If I were to create my own APRS (vector) maps for Xastir, which map 
format should I use to get the most out of it? Primarily I would like 
the maps to be directly usable with other common APRS programs as well.

Does this spell out to WinAPRS format? Or should I use the ESRI 
shapefile format, whatever that is? Are there any useful tools for 
creating vector maps from my own data, possibly by using raster maps as 
an overlay when creating the vector maps?

   Tapio