[pct-l] Re: Topo! map of PCT in California

Tom wrote: "In general distance and elevation readings taken from trail
tracings on Topo! depend entirely on how carefully and accurately one traces
the trail. If you don't have an actual line on the map that represents the
trail it is virtually impossible to reproduce the way a trail winds in and
out of gullies etc, etc, etc. For about 50% of the distance the trail was
displayed on the actual map. Under these conditions the distance and
altitude readings are very accurate. I traced the trail on level 5, the most
detailed level on Topo!"

I have found that no matter how closely I trace a trail on Topo! which
exists on the USGS quad, the traced mileage is typically 10% or more less
than the actual mileage. At least two factors contribute to this error.
First, the USGS maps themselves are not perfect. Even if they were, the
scale of the map does not allow to show every point where the trail zigs
around a shrubbery, for example. Second, the Topo! software has even less
resolution than the USGS maps when it comes to tracing a route. That is, a
trace consists of a series of short straight lines, rather than one smooth
curved line.

That being said, I look forward to Tom's post of his tracings. Will this
require the full California Topo!, or will it also work if one has only the
regional, say Sequoia-Kings Canyon, Topo!s?

AsABat

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