What's the true distance? I'm not sure, but I doubt it's 46 miles. Sierra Mapper calculates 39.4 miles (terrain) and 39.2 miles (linear). So there may be some low-balling between Road's End and Wood's Creek Crossing, and along Bubb's Creek from Junction Meadow and Road's End. Certainly, the lower terrain doesn't lend itself well to accurate trail routing. So what's going on with the Rae Lakes Loop? I'm not sure. The accepted values range from 210.4 – 212 miles. Sierra Mapper calculates the distance of the JMT to be 214.5 miles (terrain), 213.3 miles (linear). Sierra Mapper calculates the distance of the High Sierra Trail to be 72.6 miles (the '3D', terrain distance) 72.09 miles (the '2D', linear distance).

I have previously done some benchmarking: This works well for the High Sierra, but sometimes–switchbackey stuff under tree cover, e.g.–is rendered in no better accuracy than the USGS quads. I typically use a combination of satellite imagery, USGS quads, Open Cycle maps, and. Putting trails into Sierra Mapper has become an art.

It lacks the resolution of the actual trail, and sometimes, goes the wrong way altogether. I'd tell you buyer beware, but of course, I know what you paid for it ).Įarly in the process of making Sierra Mapper, I discovered that when the USGS made their quads, they didn't do a particularly good job of placing the the trail where it actually is. Well, *disclaimer*, I created Sierra Mapper. – Jungle or hilly temperate terrain………add 30% – Any loose surface material or snow (to factor in foot slippage)………add 20% – Rolling, temperate wooded terrain…………add 20% – Flat, scrub desert, or temperate terrain……………add 10% … and five two minutes of searching turned this up: … Time to hit the books! I'm sure there is something I'm missing. It seems that what I've been missing, or at least a way to get closer to a real number, is to add a figure based on elevation gain. Now I do much the same in Gmap4 but it's more accurate since I can really zoom in on the terrain and plot finer points, the effort is worth while as I can save my work to review later. Before computers I'd use a piece of string to trace the route, measure it and work out the distance knowing I had to account for elevation gain. You know, I've often wondered if there is a standard method of measuring maps that I'm not using.

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