I know the USGS and many others offer free downloadable raster topo maps for almost anywhere.
But what if I want vector maps using GPS coords? I'm new to GIS but I would assume there is a de facto free file format that works well for trail and topo maps for backpacking. What are some places I can download such files for free or for pay? I basically want a file that I can easily print or load into a GPS handheld device. Do libraries of such files exist that are as comprehensive as for example the USGS topo map download library or is there just not that much trail data that has been converted to these formats yet? I know there are many sites and apps that show trails but I want a general solution (like a standard file format) that doesn't rely on proprietary services and their particularities.