Birchbank Trail Mapping

Most of our trails were mapped back in the 1990s before the proliferation of gps units, and we did it by looking at a topo map and simply estimating where we thought the trail was on that map. Recently, I took advantage of a clear sky and clear canopy to record the trail location with a Garmin gps receiver. Steep hills and rock outcroppings can interfere with satellite signals, an effect called "bounce", and clouds and a heavy canopy can also weaken the signal. 

In the map below, the grey lines are from the existing Birchbank Mountain trail map, while the red line is the route recorded by gps. As you can see, the old-school method of trail mapping was in the right ballpark, and good enough for hiking, but the gps data is more accurate.