I'm really starting to get a handle on how to use my Edge 305 GPS cyclocomputer and to really get the most out of it, I picked up National Geographic's TOPO! software the other day at REI. The software includes detailed quadrangles for every inch of Washington state and actually already has many of the obscure forest roads mapped on it. The software imports the GPS tracks from the Edge 305, maps the route you did, quickly creates an elevation profile, and will even generated a 3D fly-over of the route by turning the contour maps into a virtual 3D relief map. You can also add notes and photos to the map.

This would all be for naught if not for the ability to export the map as either a jpeg or to the printer, complete with elevation profile and title. Here's the jpeg of the map I printed of the ride I did on Monday. Note that I turned on the shading to enhance the topography and turned off the minor roads to prevent confusion.

Naturally, there are going to be times when you want to have the map before you go and explore. Fortunately you can trace the route in TOPO! and then export that data back to the GPS device and follow along on the screen. The Edge 305 isn't a true mapping GPS as it will not display an actual topographical map on the screen, but it will show you a graphical display of the route you're supposed to follow which is good enough for times when you don't know if you need to turn right or left.

Judging by the maps (and rumors I've heard), it seems possible to follow the route I did today and turn onto a grassed-over 4WD trail that follows the powerlines around Rattlesnake Mountain and up to Tiger Mountain. Tiger Mountain is only a few miles from my house, but the direct way there is on a shoulder-less highway and not something I wish to ever ride on. If I can make a lengthy loop and work my way from the Snoqualmie Valley Trail all the way up to the Radio Towers atop Tiger Mountain, I'd be very happy. Not to mention it would be a killer workout. Sounds like the perfect opportunity to trace a route in TOPO!, export it to the Garmin, and see how well I can navigate from it.

Who says toys are for kids?


Maarten said...

You mean heading NW under the powerlines on the north side of Rattlesnake?

If I were in better shape I'd come explore with you. I'm curious but I'd be surprised if that's all passable. Topo and GreenTrails both suggest that there's a forest road from Exit 27 to about halfway down, uphill from Exit 31. And the GT suggests that if you go SE from Exit 31, you can catch the Ridge Trail Road quite a ways' SE towards the lake--but on the map the two don't connect.

For getting to Tiger... the last time I looked from the NW point of Rattlensnake downhill under the powerlines towards Hwy 18, it looked like there was a bushwacky trail there, but I don't remember that it looked very rideable.

I'm sure *someone* on the BBTC list knows more, though...

At first I thought you meant to go around the south side of Rattlesnake, but I think the watershed makes that impossible...

Doug Walsh said...

Yeah, the watershed definitely makes that impossible. There's a powerline trail on the north side of Rattlesnake Mountain that seems to parallel I-90 (sort of) and heads over to Route 18. My guess, based on TOPO! is that this powerline trail crosses the highway at one point and joins up with the road at the west end of NW Timber Trail. It seems that there are numerous roads that cut in from Route 18 and meet up with this "powerline trail".

I'm going to go exploring next week sometime. I'll post what I find.