A couple of weeks ago I reviewed the John Muir Trail Atlas, produced by Eric the Black. I used this booklet during my 2013 hike.
On my first John Muir Trail thru-hike I used something different: a combination of the Tom Harrison Map Pack (designed specifically for the JMT) and a homemade supplement which I’ll describe later.
The Tom Harrison maps are the most popular of the JMT navigation aids; they have a lot going for them.
The pack contains thirteen pages (plus a cover page), with a total weight of a trivial 2.2 ounces. The maps are numbered (for southbound hikers) starting with number thirteen and ending with number one. (This particular convention made it seem as if I was hiking the wrong way, which initially bothered the heck out of me, until I realized that I was counting down to the successful end of the thru-hike. Cool!)
They are printed on some sort of plastic that seems, at first blush, to be rather fragile. It’s not. In fact, after 222 miles of folding, wadding and getting wet, (and another few years of storage in a hot, moist environment) mine are pretty much in the same condition as the day I bought them.
The scale of the maps remains the same from sheet to sheet, and the red and highlighted trail stands out quite well.
Why did I use something different this time around? First, I didn’t like the fact that the pages were loose. I really liked having the entire hike nicely packaged in a single, bound, atlas. That allowed me to look well ahead (or behind) during breaks, lunch and at campsites. It also gave me plenty of places to note times, the number of people I saw, and other data.
(Some will tout the loose sheets as one of the Harrison pack’s best features, because you only need to carry the pages you require for the current segment of the hike. You can place sheets for the latter part of your hike in your resupply packages and send the used ones home.)
More importantly, at least for me, was the lack of two pieces of information I wanted at my fingertips: GPS waypoints and elevation profiles.
I solved the waypoint problem by adding them to the map with a pen. Then, using the National Geographic TOPO software, I marked those same waypoints and downloaded them to my Garmin GPS. (The maps are overprinted with a UTM coordinate grid, so I could have entered them into my GPS by hand, directly from the map, if I had the patience.)
I used the NG TOPO software to create elevation profiles for each day of my hike. The profiles also depicted the waypoints I had established and downloaded onto my GPS.
On the hike, I found that I used the maps rarely. The profiles were far more useful in telling me how far I had hiked that day, how far I had to go, and what sort of terrain was ahead of me. Since I could easily see what two waypoints I was between, I could quickly locate my position. I used the maps more to identify peaks and other terrain features. I didn’t use them for navigation more than two or three times. In all cases it was simply to confirm what I already decided at a trail junction.
One important caution: saying that I didn’t use the map for navigation is NOT the same as saying I didn’t need one. I would never go on a wilderness hike without a map. It may not be essential when everything is going as planned, but it can be indispensable when the plan changes.
As I make the point about the daily profiles, no doubt many of you are thinking, “Ah, have you ever heard of contour lines?”
Yep…sure have. The problem is that the Harrison maps have a fairly significant contour interval (80 feet). Also, for me at least, it’s just hard to beat a good elevation profile when imagining the ups and downs ahead.
The Tom Harrison maps are terrific navigational tools. Starting with them, and then adding, if necessary, whatever additional data you require, is a great strategy.
Good hiking, Ray