by Bob Burd » Tue Apr 23, 2013 2:22 am
by mrchad9 » Tue Apr 23, 2013 4:31 am
by boyblue » Tue Apr 23, 2013 7:00 am
Bob Burd wrote:I was back in the area today to visit another nearby peak and went over both points a second time, now equipped with a Garmin 550t. Though the absolute elevation reading isn't too accurate, I've found the relative measurement between two close points to be fairly good in other situations, within about 5ft of previously reported elevations. Today's reading showed Discovery Peak to be 18ft lower than the spot elevation point, which caught me by surprise.
Does anyone know of technical reasons why this measurement technique is not to be trusted?
by Teresa Gergen » Tue Apr 23, 2013 3:00 pm
by mrchad9 » Tue Apr 23, 2013 3:09 pm
by DougHemken » Tue Apr 23, 2013 4:08 pm
by boyblue » Tue Apr 23, 2013 4:19 pm
mrchad9 wrote:I would imagine there is an accepted confidence level/error range for topo contours... it isn't zero, but +/- something with a 95% confidence level. Anyone know?
Vertical accuracy, as applied to contour maps on all publication scales, shall be such that not more than 10 percent of the elevations tested shall be in error by more than one-half the contour interval. In checking elevations taken from the map, the apparent vertical error may be decreased by assuming a horizontal displacement within the permissible horizontal error for a map of that scale.
by Bob Burd » Tue Apr 23, 2013 4:58 pm
by sierraman » Tue Apr 23, 2013 5:23 pm
by DougHemken » Tue Apr 23, 2013 6:30 pm