This post launches a new category at GPS Tracklog -- Trip Reports. The point isn't to provide a trail guide, but rather to exhibit some of the ways to utilize your GPS. This report focuses on a circumnavigation of Mt. Diablo, a 3849' peak that dominates the eastern side of the San Francisco Bay region.
My wife and I were in the area this past week doing GPS mapping demos, promoting my book, GPS Mapping - Make Your Own Maps. Since our days were open, we decided to get in a mid-week bike ride. Living on California's heat-deprived North Coast, we opted for a ride slightly inland. Mt. Diablo was our target, and since I didn't know the area very well, I turned to a message board on mtbr.com for help. I wasn't disappointed. Several people, especially EBrider helped out, designing an awesome loop that incorporated technical single track, loose and steep fire roads, and nearly 2,000' of elevation gain.
EB sent me a track in the form of a .tpo file, which is a National Geographic TOPO! (Amazon link) file format. This, combined with the trail descriptions provided by EB and others at mtbr.com, gave me almost enough info to plan the trip, though I will admit to picking up a hard copy of a trail map so that I had good access to trail names and other features. Too bad the Mount Diablo Interpretive Association doesn't have this map posted online. Online trail maps (often PDFs), combined with mapping software and aerial photos, are typically adequate for my purposes.
I took the track that EB sent and exported it from TOPO via my GPS (a real pain since TOPO makes you convert tracks to routes in order to export them). I then imported it into TopoFusion, which allowed me to see the track on a color aerial photo. USGS posts color urban aerial imagery for major US metropolitan regions online at TerraServer, with more locations being added on a frequent basis. These images are readily available in programs like TopoFusion and USAPhotoMaps, which add a better user interface and allow you to transfer data to and from your GPS. The color imagery extends into natural areas in many cases, and the detail is amazing, going down to 0.25 meters per pixel. Notice the waypoint (MDNPEAKTR) in the image at the right. You can see a fire road going off to the north from the waypoint and, while the online image isn't as sharp as the original, you can actually make out single-track going off to the northeast! The single-track leaves the image near the top of the right-side.
With TopoFusion, I traced the single-track as accurately as possible, and created waypoints for major trail junctions. I then loaded the waypoints and redrawn track to my GPS, making the track blue so that I could clearly distinguish it from the tracklog being created as I rode.
The only things left were to create a route to guide me from waypoint to waypoint, and generate a printed map. I've posted the ride at 4 meters per pixel (black & white) using TopoFusion's PhotoFusion feature, which apparently doesn't yet allow access to the color aerial imagery when using their HTML Image Map feature.
EDIT: I asked at the TopoFusion message board and found out that you can capture a color aerial .jpg and replace the one generated by TopoFusion. My Mt. Diablo PhotoFusion page now shows the color aerial at 4 meters/pixel..
If you want to to learn more about how to use GPS and mapping software, check out my book. It has chapters on National Geographic TOPO!, USA PhotoMaps and TopoFusion. And for those of you who want to know more about the ride itself, read on...