sakau2007

I have a couple different apps and mapping utilities and I am curious how much climbing I am actually doing, however the elevation changes can be wildly different from one app or service to the next. I don't have a dedicated cycling computer... just a phone I carry with me on my rides.

Seattle Forrest

The best way to calculate elevation change is to use a barometric altimeter and to keep it calibrated. GPS is not very good for altitude, a barometer is much better. A lot of newer smartphones have barometers in them, see if yours does.

If not, there are many services that will "correct" the elevation of a GPS track. They ignore the altitude readings from your phone, and look up what was the true altitude for the lat/lon coordinates your phone recorded for you. This mostly works pretty well, but it's usually less accurate than a barometer in my experience. GPS has some horizontal error; if you ride next to a river or a cliff, side-to-side jitter can make it look like you went up and down many times.

sakau2007

I use the iPhone 6+ with mapmyride app. When I get home from my ride, I can then view the total climb by looking at the route I took. I have no idea how accurate this is, however, whenever I ride the app does a really good job of keeping me on my route. It never has me jumping from side to side. In fact, it can even detect pretty well when I say, drift from the shoulder towards the middle of the road. So I feel like the route is very accurate, but I just have no idea if the altitude built into the maps that it uses is accurate.

KenshiBiker

There's your problem right there. Like the old saying, "A man with two watches is never sure what time it is."

sakau2007

I only use one app at a time. I've just compared them on the same route to see if I get the same result, and I don't always get the same result. I can spit a route into several different maps engines online and try to get the total climb but I don't know which ones are accurate and which ones aren't.

As for your analogy, that's great... so could you just tell me which watch is accurate? Because that's really all my question boils down to.

Seattle Forrest

To check the accuracy of your recorded track (because if you want to run elevation corrections, that's what you're going to use), you can set it to satellite view and zoom in pretty close (like 20 meters) and examine the path it recorded for you. When you navigate, it has some allowances built in.

Apparently your phone has a baro sensor in it. I'm used to Android so I have no idea how you'd use it on your Apple. But if the sensor is good hardware, this is absolutely your best bet.

iPhone 6 and 6 Plus both have barometers that could help crowdsource hyperlocal weather.

Seattle Forrest

That's to be expected. You were using GPS (for altitude), and it sounds like you got different results on different days. Things like temperate, humidity, cloud cover, etc all have strong effects on GPS accuracy. Probably the apps contribute to this, too. (I've heard lots of people say Strava is the worst for altitude gain, they just roll some dice and tell you what the numbers say.)

sakau2007

No I wasn't using GPS for altitude. At least not live GPS.

Let's ignore apps for a minute because my routes are pretty much the same. If I don't even have my phone with me, I can come home, manually put in the route on mapmyride and it shows me elevation change based on those roads. I just need to know how accurate that is. If the data in mapmyride's map database is good, then it should be fine.

Seattle Forrest

I see. That's a harder question to answer. I don't know what's in their database. Found these with a quick Google:

Map My Ride Elevation Accuracy? - Cycle North Carolina
Elevation profiles in MapMyRIde
Map My Ride vs. Ride with GPS - The Paceline Forum
MapMyRide accuracy - The Paceline Forum
What is more accurate Garmin or Mapmyride?

I take random posts on the internet with a grain of salt but they're all saying Map My Ride gives too low elevation gain figures.

pdlamb

Climbing elevation is the geography equivalent of calories burned. Lots of ways to come to an answer, but you need either a survey or a lab test for oxygen consumption to get even close to definitive.

That said, you should look at Delorme Topo if you want a big number. One route I looked at was about 100% over; it was a road built on an old railroad bed climbing a mountain, and I'm pretty sure there's no drop on that route. Topo interpolates between topo lines on the map, so its profile looked like a sawtooth.