My Forerunner 305 is often less accurate than that. For example, telling me I'm at 80ft elevation when I'm at maybe 10ft above sea level. Because of that I don't trust the instantaneous % grade estimates either.kdub said:The altitude reading on the 305 is pretty accurate. Because the elevation sign on the mountain is prettty much the same as what the Garmin tells me. Perhaps +/- 2-5 feet variance only.
Both. Not sure of the exact operational details, but it does use gps to calibrate the barometer on startup.Touch0Gray said:is the 305 barometric?...or does it go by gps?....if barometric....it either needs to be calibrated to compensate for barometric pressure, or be "self calibrating"
If it goes by gps....then reflected "noise" can seriously interfere with elevation readings