route mapping sites: height profiles are useless

[inaperfectworld]

i've used bike toaster and bikehike to plot the same route (in vercors): distances and start and finish heghts are spot on but bikehike says the height gain was 2626 metres but bike toaster 3638m. another route gives 1227m bike hike vs. 1847 toaster. so figures disagree so wildly as to be valueless. i suppose it depends on the sampling interval of the route, does anyone know of an accurate site?

 

[fossyant]

I don't think you'll get it - only a GPS unit may give the info you require.

 

[akaAndrew]

i suppose it depends on the sampling interval of the route

and the algorithm the site uses.

Ime, mapmyride is the worst of the lot. I've had 200km GPS logged rides show up as 1000m less climbing on mapmyride! I live in an hilly area but no long climbs, all rolling valleys and hills, so maybe that's the sort of terrain mmr does not handle well. People have mentioned it on the mmr forum but the staffers defend their algorithm.

As to a more accurate site, I don't honestly know. I did find one that gave values closer to those recorded by my GPS but in all honesty I can't remember which one it was (maybe toaster but I've also used openrunner, coursemapper and a few others in the past). Plus it may have only been more accurate for the kind of terrain I was riding too. These days I don't look at the numbers, I just plot my ride and look at the elevation profile because, as you say, the numbers are all over the place.

 

[Crackle]

Mapmyride is not good at rolling terrain. I think if the climb is less than 50 feet it doesn't count it. On longer climbs it's more accurate, I find. Bikely, et al, over exaggerate the climbing.

 

[lukesdad]

they re all pretty useless.

 

[nigelnorris]

Do they work using something like OS contour lines, so if you don't cross one then the change isn't registered?

There's a similar problem with the Nokia Sports Tracker distance measuring software, doesn't measure changes less than than the GPS limit, about 15m?

 

[jimboalee]

In the old days.....

OS map, ruler, large sheet of paper and sliderule.

Not so long ago....

OS map, MS Excel.

Very recently....

OS map, Only look at the hills with a chevron.

Now…..

Streetmap.co.uk Only investigate what I see as steep ones.



I have a Sony 15" laptop. I am so lucky that Streetmap at 1:25,000 gives 500m on the map = 5cm on the plastic ruler. If your screen does not match up with a plastic rule, make a dedicated scaler with a piece of cardboard. I had to do this with a 4:3 ratio Dell monitor.
I scale off the distances between the contours and construct a little Excel table of Dist vs Elevation.
Contours 5mm apart on the screen = 10%. When I see a bunch of contours less than 5mm apart, I investigate it.
This is about as accurate as I've been able to get.

Measuring the total climbing of a 200 km Rando is a balls aching task. A 100 km Populaire is a lengthy process, so I don't bother. Only 10% and steeper so I can prepare.

 

[Spinney]

In some ways it doesn't matter to much, as long as they are consistent (but I don't know if they are!).

For example - you put a sportive or audax route into bikehike, and it tells you the height gain. You put your previous hardest route into bikehike, and compare the two height gains. This will give you an idea of how hard the forthcoming ride is compared to what you can already do.

(I count the arrows as well!)

 

[jimboalee]

It's not so much the difficulty of the whole ride, it's knowing WHERE the hills are and at what time you will reach them.
With this knowledge, you can shove some carbs down your throat 1/4 hour before you get to them.
You will also know how long the flat stretches are, so you can gauge your carb depletion.

 

[akaAndrew]

...or you could just ride

 

[peanut]

I thought the Bikehike profile gave altitude and climbing in feet not metres .
The total height climbed incudes every little rise.
If you want an accurate guide you can look at the OS map for the area.

 

[jimboalee]

...or you could just ride

Yeh, ride a 300km Audax rando relying on more luck than judgement?

They might not look like they know what they're doing. That's the quality of a superior sportsman "Making a difficult thing look easy", ( as opposed to a 'clever' Engineer. )

 

[akaAndrew]

Yeh, ride a 300km Audax rando relying on more luck than judgement?

I'd probably rely on the route sheet!

Don't all Audax events publish the amount of climbing? Certainly they all do if there are climbing points involved. That's enough for most audaxers to make a simple 'do it' or not decision.

Whilst I do often look at a ride profile (either on a map or a mapping site), I can't honestly say I've ever concerned myself with exactly when the climbs come in terms of a fuelling strategy. That's just too much science for my liking! Perhaps I'm not taking it seriously enough?

 

[jimboalee]

I'd probably rely on the route sheet!

Don't all Audax events publish the amount of climbing? Certainly they all do if there are climbing points involved. That's enough for most audaxers to make a simple 'do it' or not decision.

Whilst I do often look at a ride profile (either on a map or a mapping site), I can't honestly say I've ever concerned myself with exactly when the climbs come in terms of a fuelling strategy. That's just too much science for my liking! Perhaps I'm not taking it seriously enough?

Climbing a hill ( 12% for instance ) burns 3 - 4 times as much energy as riding on the flat, in kCals/min terms.

So a calorie usage of 25 kCals per minute for a 10 minute climb is not to be sniffed at as 'ridable' after an hour since you last ate something.

A big chunk of Kendal Mint Cake does the trick 10 minutes or so before the approaching climb.

 

[akaAndrew]

I'm sure you are right jimbo.