How do you calculate how far you've climbed?

[hilldweller]

I see that several of you are very precise about how much climbing you've done, and sometimes mention what the gradient was. How do you work that out? Is it some flash bike computer thingy?

I just use contour lines on a topo map and subtract lowest point from highest point. That gives a reliable ballpark figure but doesn't take account of small ups and downs and isn't detailed enough to calculate gradient from.

[Eden]

You can use a web based program like Map My Ride. Some people have Garmin computers that use GPS and some bike computers have elevation that is calculated with barometric pressure. All of these methods have their margins of error, some are better than others, but all will give you an estimate.

[hilldweller]

Thanks Eden. That Mapmyride programme is amazing and some helpful soul has mapped lots of rides in my local area, including the loop that goes past my house :D

[OakLeaf]

In my experience mapmyride severely understates elevation gain, compared to any GPS in our riding groups, MotionBased, or SportTracks correction.

The ride I did on Saturday was 4100 feet according to my Garmin 705, 4400 feet according to another rider's 305, and I believe 1700 (maybe less) according to mapmyride. The rider with the 305 was of the opinion that his GPS understates elevation gain by about 10%. Unfortunately my data file got corrupted, so I wasn't able to upload it into SportTracks, which IMO is the most accurate of all.

[hilldweller]

That's interesting. For the routes I was looking at near where I live it looked pretty accurate i.e. lined up with what I'd expected based on the topographical map - and that IS accurate. Maybe it varies. Could the Garmins be overestimating? (I have no idea how they work :confused:)

[OakLeaf]

The Garmin Edge series has a barometric altimeter, software corrected against known locations, and are considered the most accurate bike computers on the market. Barometric is WAY more accurate than GPS points, just because of the nature of the triangulation from satellites high above the ground, and with the correction against known points, it eliminates some (but not all!) of the inaccuracies that come from air pressure variations.

The software programs I mentioned, MotionBased (online) and SportTracks (downloadable) add another level of correction to uploaded GPS data. MotionBased does tend to overestimate, it seems. SportTracks has my confidence mainly because it (1) reliably corrects distances on the occasions when there's a problem with my GPS; (2) gives elevation figures in flat terrain that seem pretty reasonable, when everything else will really overestimate just because of little pressure variations of a foot or two at a time; (3) usually matches total ascent and descent pretty closely for a ride that starts and ends in the same place; and (4) can vary in either direction from my raw 705 numbers rather than consistently being higher or lower.

Just looking at topo maps, as you point out, is probably reasonably close for long steady climbs and descents, but in rolling terrain, most of the climbing won't even register on a topo map that's laid out in 200 foot contour lines. Surely yours must be narrower than 100 meters!? In areas where the climbs are short but very steep, like Ohio, climbs of 150 foot (50 m) gain at over 10% grade surely do count in your legs. So it depends on where you are I suppose.


ETA: for real-time grade, there's a very low-tech bubble level type of device (http://www.adventurecycling.org/store/index.cfm/product/193_25/sky-mounti-inclinometer.cfm) in the Adventure Cycling catalog. It doesn't store data obviously, but for just glancing down and seeing how steep the hill is that you're climbing at the moment, you don't get any more accurate than a gravity-based device! :)

[kfergos]

In my experience mapmyride severely understates elevation gain, compared to any GPS in our riding groups, MotionBased, or SportTracks correction.

The ride I did on Saturday was 4100 feet according to my Garmin 705, 4400 feet according to another rider's 305, and I believe 1700 (maybe less) according to mapmyride. The rider with the 305 was of the opinion that his GPS understates elevation gain by about 10%. Unfortunately my data file got corrupted, so I wasn't able to upload it into SportTracks, which IMO is the most accurate of all.

I think all Map My Ride does is subtract the very lowest elevation from the very highest elevation and call that to total elevation. It doesn't actually add up the total climbing, which is what you really want. I did a century last year that had 7,000 feet of climbing according to the organizers, but Map My Ride said it was something like 1,500 feet of elevation gain. After doing it, I have to agree with the organizers -- that ride was ALL rollers, so it didn't actually have a huge difference in elevation, which is what I think MMR looked at, but it was endless climbing nevertheless.

I have a Garmin but have never figured out how to get total amount of climbing out of it, although I'm sure the numbers are there (I've never used SportTracks but now I look at it, I will definitely have to). Also, it seems really inaccurate on the % grade -- I've ridden up the same hill multiple times and had it tell me everything from 10% to 25% :eek:, so now if it's a big hill, I just check the elevation at the bottom and then at the top and subtract - not all that different from the OP's method of checking contour lines! :p Incidentally, I think the GPS is only guaranteed accurate to about 15 feet, a variation that can make a pretty huge difference in the reported % grade of a hill!

[OakLeaf]

I have a Garmin but have never figured out how to get total amount of climbing out of it

On my Edge 705, it's Settings:BikeComputer (either 1 or 2, these are two displays that you can toggle back and forth): Data Fields. Then you can select the number of data fields you want in each display, and choose what data you want to show. Total Ascent is one of them.

My Forerunner 301 does not have the option to display total ascent on the unit. Not sure about later Forerunner models.**

Regardless of whether you can or do display it during your ride, total ascent will be shown in the Totals pane of Training Center.



**total covetousness hijack: didja see they're finally coming out with a successor to the Forerunner 305, which will have the same size display as the 305 on a smaller unit, HR-based calorie calculation, 50 meter water resistance for triathletes, power meter support, better battery life... droool...

[SadieKate]

The Garmin Edge series has a barometric altimeter, software corrected against known locations, and are considered the most accurate bike computers on the market. Barometric is WAY more accurate than GPS points, just because of the nature of the triangulation from satellites high above the ground, and with the correction against known points, it eliminates some (but not all!) of the inaccuracies that come from air pressure variations.

The software programs I mentioned, MotionBased (online) and SportTracks (downloadable) add another level of correction to uploaded GPS data. MotionBased does tend to overestimate, it seems. SportTracks has my confidence mainly because it (1) reliably corrects distances on the occasions when there's a problem with my GPS; (2) gives elevation figures in flat terrain that seem pretty reasonable, when everything else will really overestimate just because of little pressure variations of a foot or two at a time; (3) usually matches total ascent and descent pretty closely for a ride that starts and ends in the same place; and (4) can vary in either direction from my raw 705 numbers rather than consistently being higher or lower.
Most excellent explanation! I may steal this sometime.

kfergos, do a search on SportTracks and you'll see some discussion of the plug-ins which make SportTracks such a tremendous application.

[hilldweller]

Just looking at topo maps, as you point out, is probably reasonably close for long steady climbs and descents, but in rolling terrain, most of the climbing won't even register on a topo map that's laid out in 200 foot contour lines. Surely yours must be narrower than 100 meters!? In areas where the climbs are short but very steep, like Ohio, climbs of 150 foot (50 m) gain at over 10% grade surely do count in your legs. So it depends on where you are I suppose.


Thanks for that detailed reply Oakleaf. I think I'm starting to get an idea how they work now. The NZ topo maps have contour bands at 20m (60-something ft) intervals, which is pretty detailed really. I'll have to see if I know anyone with a Garmin or something similar and see how much difference all the little ups and downs makes. Could be quite a lot on rolling terrain. As you say, depends what sort of roads you're riding.

[msincredible]

I use:

Bikely (http://www.bikely.com/), which does calculate total climbing. It works well on some routes and not so well on other routes (according to my estimates and to friends with Garmins).

My VDO cyclocomputer which just uses barometric pressure. If the weather is nice all day, it does pretty well, but it gets easily confused in all our microclimates. Climbing in the rain the other day, I suddenly saw myself on a 54% grade! :eek: :p