I would use a program like OziExplorer without question. I have done such a thing as you are attempting numerous times. It’s all about callibration. You transfer a set of known points (landmarks) onto the “trail map” and then generate a fully calibrated map. I was always disturbed by having one map (topo)that was accurate, but outdated (or with no trails on it), and another map with features, including trails at times. You can even import the OTHER way around by transfering information on the trail map to the topo !

George

I’d suggest worldKit. The process is straightforward, but here are just the major points in building a map.
Start off with a USGS topo, callibrated by MapProxy. Walk the trails, and convert the gps track log to geocoded RSS (a bit of perl scripting would do it). Then publish it all together in a worldKit map, using the <track> log view feature.

From the sounds of your email message, the trail map that is available is not accurate or not detailed enough to be helpful when in the field. Is this correct? Are you interested in hiking the trails? If so, is it too obvious to suggest hiking the trails with your GPS on then downloading the points collected through the tracking feature to the National Geographic program? You can match the settings on the program with those on your GPS and end up with a topo map that has the trails on it. Once you have all the waypoints on the topo, just connect them using the Route Tool. Then you will have the distance and elevation change for each trail too.

Just download your track to trackmaker GPS mapping software that out puts as geographic info systems maps and projections. (it’s freeware) you need a pc to garmin data cable with either an usb adabter or to the pinport. I believe that trackmaker will aslo allow you to import a raster map background. Try 3DEM, also free, you can import your tracks to elevation models that have a topo mapping feature.
If you want to play with a whole GIS system with many options that is free try MicroDem. You also can match imagery or topo maps to tracks in some of these software. Try terraserver and import to photoshop or illustrator for mapping from arial photography, Lewis

Thanks for all the advice - I thought of walking the trails with the gps - I wondered about the accuracy (100 - 200 ft.)

I will try several of the suggested options.

Brod