[at-l] re: Pittsburg(h)

[nightwalker.at at gmail.com (Nightwalker)]

Walt Daniels <wdlists@optonline.net> wrote:
> Wheeling mileages and GPS mileages measure different things. In steep
> and
> rocky/twisty terrain, GPS is frequently 10-20% lower than wheel
> mileages.
>
Not when you use USGS 10m DEM files as your Z factor for your calculations.

I export my 2-second track files, long and lat only, and export the
underlying elevation from the mapping program. The differences are much less
than 1%.

However, you don't use the GPS file for mileage unless you don't have use of
a wheel. The GPS-to-computer recorded tracks are for creating the mapped
tracks that you see overlaid on the USGS and ATC, GATC etc. topo maps. The
GPS is just one mapping tool among many.

I've made a number of recreational maps, and hope to make quite a few more.
Believe it or not, some people originally thought that my trailname should
have been Mapster.  :-)