So for a basic 4 mile neighborhood loop, I get different measurements (off by .1 to .2 miles) when comparing my Garmin 305 vs distances calculated by Runningmap.com. Assume that I've input the run carefully into the web site, cutting tangents, etc.
Which is more accurate? I'm inclined to trust the website.
You should probably do a couple more tests. I would map it on another site several times (www.gmap-pedometer.com is the best).
Then I would drive it. Then I would bike it, see what the speedometer comes up with. Then I'd wheel it. It's only four miles so it won't take too long.
Let us know what you come up with.
Garmiman wrote:
So for a basic 4 mile neighborhood loop, I get different measurements (off by .1 to .2 miles) when comparing my Garmin 305 vs distances calculated by Runningmap.com. Assume that I've input the run carefully into the web site, cutting tangents, etc.
Which is more accurate? I'm inclined to trust the website.
what percentage of the run is that? I feel like that's more meaningful than ".1 or .2 miles."
I'm inclined to say Garmin, but odds are neither is exactly right.
Have you ever viewed your route using the GPS in Google Earth? It's never an accurate representation of the path you ran. It's a handy tool for estimating, but that's it.
If you want the best measurement without going out with a wheel for 15 miles, use
, switch to satellite view, zoom in all the way, turn off mile markers, check the manually (straight lines), and start mapping, to the best of your ability, the route you ran.
Any elevation gain during the run is negligible if it's just a training run. Let's take an example.
Suppose you run a constant 5% grade the entire run (5% uphill and then 5% downhill). This equates with going a vertical distance of 264 feet for every 5280 horizontal feet (1 mile) you calculate using gmaps. 264/5280*100 = 5%. Using simple trigonometry we see the hypotenuse (the distance you actually ran) is 5286.6 feet long. You ran an extra 6.6 feet. Multiply that by how many miles you actually ran and the number is insignificant. It would be significant if you were certifying a course, but then you would never use a mapping tool like gmaps in the first place obviously.
%5 is a pretty steep grade too, the extra length would be even less with a lower grade.
My belief is that gmap-pedometer always overestimates a bit (0.1 to 0.2 miles for a 5 mile course)