GPS Fun on the Mt Tecumseh Trail 7/25/2013

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Home: Northwest CT Avatar: Madison 1985
I suppose I could have posted this under the “GPS Questions” or “Technology and Hiking” threads, but I figured I haven’t done a trip report yet, so why not? This will be as much about my playing with the GPS than about the hike itself. Besides, HubHiker did a nice report on this trail only a few days earlier, which I was glad to read.

I wanted to play with the GPS I’d been learning to use over the last month or so. Thursday was forecast to be about as nice a day as it gets. I figured the Mt Tecumseh Trail would be a good target for me, I might even be able to make it to the summit. Before heading north, I started with the track for the trail I had downloaded. Using Basecamp, I converted it into a route. Then, I created waypoints for the summit, and the first intersection with the Sosman Trail, and added them to the route and put it all on the GPS.

The day began on a good note before even reaching the trailhead. As I headed up RT49, I spotted a large mama moose in the road. I pulled to a stop, and soon she cleared the road, and just as she did so, young ‘uns 1 & 2 stepped into the road, stood in the middle of it a few minutes, and then followed mama into the woods on the other side. Maybe the same one HubHiker saw. After the moose left the road, I completed the drive to the ski area parking lot. I think there were 3 or 4 cars already there, and I parked and got myself ready. The other nice thing was it was quite cool and low humidity, I started off with a temperature under 60 and a jacket on.

At the trailhead, I calibrated the GPS compass and altimeter, choosing to calibrate the altitude to the trailhead altitude published in the WMG. Clear the trip computer data, clear the “current track”. Tell it to “find” the route I had created, and set off up the trail. Almost immediately, there is a sign from Waterville Valley to the effect that the trail is public and folks a welcome to use it, but you need a pass to use the ski trails. I wasn’t planning to hike the ski trails.

After a few tenths, I had warmed up, and started doffing the jacket, and wouldn’t you know, I had just gotten the left arm out of the sleeve and put that backpack strap back on when I encountered the first crossing of Mt Tecumseh Brook. Not a problem, didn’t even pause in getting the other arm free while I crossed. I encountered the blowdown that HutHiker described, about .8 from the trailhead, according to the GPS and a few tenths before the second brook crossing. I chose to go over, but would later learn that there is a path around it on the downhill side, and that is really the way to go. The track displayed on the GPS was pretty close to the one I had loaded, and the trail is for the most part wide and well marked. A little mud and running water in the trail, especially the lower part, but easy enough to deal with.

I found that having the GPS displaying my progress was a great morale builder for me. I liked knowing, at a glance, how far up I had climbed, how much altitude was left to go; how far I’d gone and had left. When I reached the viewpoint, I marked it as a waypoint, and took in my first view of the day. Heading upward on the trail, I soon encountered a couple headed down. Would only see three others.

It’s a nice trail, with some nice rock steps at various points – thanks Rocket21 and Eric.

About a half mile from the Sosman trail intersection, I noticed something odd with the GPS – the trip computer stopped displaying the distance and ETA to the next waypoint. That’s odd. Maybe because I’m stopped. Check again after walking for 5 minutes. Still nothing. Hit “Find” and the route, and I’m back in business. But shortly, the GPS tells me I’ve reached “point 249” and the route stops. Turns out, on the Garmin GPSmap 62s, tracks can have 10,000 points, but *routes* can only have 250. Ok, the track is still displaying, and I found that pretty much just as good. Punched in the Sosman intersection, and set off. In a little bit, while I’m fiddling with the unit, a voice says “hello” from the trail below. I say “hello” to a fellow headed up. I tell him that the GPS says it’s about a half mile to the summit, and 500 ft of climbing, that I’m awfully slow, and feel free to pass me. He does and says he’ll see me at the top. “Hope so”, I reply. Soon I reach the intersection with the Sosman Trail, and punch the summit into the GPS. Not long after that, I reach the second Sosman intersection, and as I look at the sign that says “summit” with arrows in two directions, a couple emerges from the Sosman trail, and we chat a few minutes.

I continue on the Mt Tecumseh Trail, and in a few minutes, the “low battery” warning pops up. Now, yes, they are Radio Shack Ni-MH’s of questionable vintage, and I’m a pretty slow hiker, but still…I kept it mostly on the map display, with the battery saver turned on… A couple minutes later and they are dead. Put in the spares and continue the short climb to the summit. Mark the summit as a waypoint, and save the track. I take in the view through the trees. I note that the climb took me 135% of book time, I guess that’s what I’m good for nowadays.

I’d brought a couple of ham sandwiches and an apple, but I’m not hungry so they stay in the pack. No one else around. Figure that the guy that passed me must have come down the Sosman while I was climbing the Mt Tecumseh. Clear the trip computer, clear the current track, and start to head down. Punch in the Sosman intersection. Reach it, punch in the waypoint I’d created on the way up for the viewpoint. After a half hour or so, I look at the CDI on the compass display, and it’s pointing pretty much in the opposite direction of where I figure it ought to. I remember that DougPaul had told me I should recalibrate the compass after changing the batteries, and I hadn’t done that. Calibrate the compass. The CDI looks closer to where I think it ought to be, but still I think I’d be reluctant to rely on it solely.

Shortly after the upper brook crossing, I hear a voice – it’s the guy that passed me on the way up. Turns out he had mistakenly started down the part of the trail that heads to Tripoli Road. He tells me he has a GPS too, and after a while he realized his error and turned around. I offer to let him pass, but he says he’s fine. When we reach the blowdown, I start over it, as I did on the way up. He tells me there is a path on the downhill side. I tell him, I’m halfway through, too late to change. When I emerge, he’s caught up to me, so clearly the path on the downhill side is the way to go. After a minute or two, he says, “I will go by, if you don’t mind.”, and I step aside. In about 20 feet he trips a bit, and catches himself. I tell him, don’t worry, I’ve done that 3 or 4 times myself today. So I fibbed. It was more like 6 or 7 for me :) I decide I’d like to push myself a bit, and see if I can keep up with him, so I follow at a decent distance, but keep him in sight until we both reach the trailhead, where ours are the only two cars in the lot. We chat a bit on the way to our cars and say goodbye. I stow my gear and change my shoes for the 5 hour trip back to Connecticut.

Had a nice hike on a nice day – even got to the top!

Some GPS questions:

So what is the difference between a track and a route, and why use one over the other? Especially if a route is limited to 250 points, and a track isn’t?

One reason I had decided to use a route, was that after making a track of a trail in Connecticut, I’d made a route of it, and then followed it, and whenever I passed a route point, the GPS would beep at me in confirmation. But it didn’t do that on this trip. Any hints on what’s going on with that?

When I got to the summit, the trip computer said something like 3.8 miles. The WMG says 2.5. And when I got home and loaded the tracks into Basecamp, they said 2.8 up and 2.4 down. Fractal math?
 
If I have a track, I load it, and just follow along, making sure my active log follows the existing track. If I don't have a track, I can make a route by connecting together a series of waypoints. I rarely do the latter, but I always do the former. I don't need to know exactly how far to the next waypoint.

Over the years, I've taken the free set of tracks and broken them down into geographically convenient chunks. Like "FranconiaRidge.gpx" which contains all the trails you might need / see on the FR Traverse. I load up the one for the day's plans and it contains all the variations / "escape routes".

Tim
 
At the trailhead, I calibrated the GPS compass and altimeter, choosing to calibrate the altitude to the trailhead altitude published in the WMG.
FWIW, I use the (altitude) autocalibration. Saves time (or forgetting) at the trailhead. I've generally found it to be quite accurate. (However it takes a while, but since I generally use the GPS during the drive to the trailhead (2.5+ hrs) it is calibrated by the time I get there. My magnetic compass doesn't need calibration (and rarely leaves my pack).

I continue on the Mt Tecumseh Trail, and in a few minutes, the “low battery” warning pops up. Now, yes, they are Radio Shack Ni-MH’s of questionable vintage, and I’m a pretty slow hiker, but still…I kept it mostly on the map display, with the battery saver turned on… A couple minutes later and they are dead. Put in the spares and continue the short climb to the summit.
I use one set of NiMH batteries during the drive up and swap in a fresh set of fully charged NiMH batteries at the trailhead. (Still had 2 bars after hiking for 14 hrs yesterday.)

I also test the capacity of my NiMH batteries occasionally and eliminate the weak ones.

I wouldn't use the battery saver--it increases the battery life somewhat but also increases the position error by a factor of ~3. See http://www.vftt.org/forums/showthread.php?38355-60CSx-battery-lifetimes

BTW I also don't use WAAS. The WAAS satellites are low on the horizon and are often lost. The net effect is that the apparent position jumps back and forth.

I look at the CDI on the compass display, and it’s pointing pretty much in the opposite direction of where I figure it ought to. I remember that DougPaul had told me I should recalibrate the compass after changing the batteries, and I hadn’t done that. Calibrate the compass. The CDI looks closer to where I think it ought to be, but still I think I’d be reluctant to rely on it solely.
FWIW I find the bearing display to be more useful than the course display when hiking.

Some GPS questions:

So what is the difference between a track and a route, and why use one over the other? Especially if a route is limited to 250 points, and a track isn’t?
A track is a record of where you have been. Essentially an electronic breadcrumb trail. A route is a sequence of waypoints.

One reason I had decided to use a route, was that after making a track of a trail in Connecticut, I’d made a route of it, and then followed it, and whenever I passed a route point, the GPS would beep at me in confirmation. But it didn’t do that on this trip. Any hints on what’s going on with that?
No idea--I've never converted a track into a route. If I want to follow a prior track, I'll just store it as a saved track and follow it on the screen.

When I got to the summit, the trip computer said something like 3.8 miles. The WMG says 2.5. And when I got home and loaded the tracks into Basecamp, they said 2.8 up and 2.4 down. Fractal math?
All methods of estimating the length of a trail have errors. (And to make it worse, the length of a trail is a fractal so there is no uniquely correct length.)

The trip computer runs off the one position per second output of the core GPS. The track is a subset of the one per second positions (depending upon the track recording settings). So the distances are computed from different datasets. Also the GPS positions have errors so every time you walk a path you will get an (at least) slightly different track.

(BTW, maps have errors too--often much greater than the GPS errors.)

Doug
 
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