The data were collected from standard USGS topographic maps.
Rather than measure fixed distances along the roads and guess at the elevation
for each point,
I chose to take distance measurements at every contour interval.
For long intervals and known retrogrades, I interpolated other values as well.
There are a number of sources of error in my technique:
Note also that since I am measuring horizontal distances,
the distance along the X-axis should be shorter than the actual distance
you would travel along the road.
- Each segment was measured individually at 1/32" granularity.
The potential accumulated error is considerable.
- Measuring short segments along twisty roads with a straight ruler
- The accuracy of the sampling is inversely proportional to the
quantity of beer consumed by the sampler.