This question came about due to manually entering Summit coordinates in my GPS. There are several ways and places to acquire these coordinates. Where you acquire them can make more difference than I would ever have expected. My example is Summit W3/PD-029 Eagle Rock West. Going to the Summit Page on SOTAwatch indicates coordinates of 40 14 27 N, 76 22 22 W. These coordinates took me to the wrong place. Investigating the discrepancy lead to the conclusion that perhaps rounding and truncating errors are responsible.

A friend had acquired coordinates via the SOTA W3 Association GPX File ( 40.24113000, -76.37283000 ). The SOTA W3 Google Map matches those coordinates exactly. 40.24113000, -76.37283000 converts to 40 14 28.07 N, 76 22 22.19 W.

The SOTAwatch Google Map indicates coordinates of 40 14 28.0 N, 76 22 22.1 W ( Google also shows this as 40.241100, -76.372803 ). The SOTA Mapping Project shows these same coordinates rounded to 40.24110 N, -76.37280 W and 40 14 28 N, -76 22 22 W.

Using a piece of Geocaching freeware, FizzyCalc, the resulting conversion for the Decimal Coordinates is 40 14 27.96 N, 76 22 22.08 (or 22.09) W.

It seems that the Summit Page on SOTAwatch coordinates are then strictly truncated to the integer component. A 1 second error here is a difference of 101.195 feet, (thus out of our association AZ). Now that I have experienced this, I will not again rely on Summit Page on SOTAwatch coordinates. Is this a special outlier case not worthy of concern, or is it an issue of interest to SOTA? Which of these many mentioned coordinates is the true position of W3/PD-029 Eagle Rock West?

Glenn - AB3TQ