Mapping discrepancies

[HaloJ]

Morning all,

I've been looking at a new 10 mile evening route for the other half as we're moving in together shortly. Anyway the two mapping systems I used show wild discrepancies in their altitude data. I wondered if anyone could advise on which is the more accurate without me having to do a trial GPS run.

http://www.mapmyride.com/route/gb/barnet/495126994053510208

http://gb.mapometer.com/en/cycling/route_491221.html

Thanks,

Abs

 

[PpPete]

I don't use either of those websites, but I agree there are lots of discrepancies!

Your route in bikehike shows at 158m ascent, 164 m descent (!!!)
in bikeroutetoaster it is 108m ascent and descent

So far as I am aware both are derived from the same terrain database, but use different calculation methods for intermediate points.

Unless your GPS has a barometric altimeter it will also give different results depending on how frequently it records track points (you can modify that setting on many models)

 

[zacklaws]

I think you will find the "Mapometer" site iffy. As I have never seen it before, I just did a route in my local area and oddly enough it came up with that figure of 705' but then it corrected itself eventually to a new figure, plus a "Refresh Altitude" button appeared which you do not have.

But I have just noticed that your route has suddenly had a rethink and there is now not much difference between the two websites, but the "refresh altitude" button has not appeared?

 

[HaloJ]

Thanks for looking guys. I've just compared bikeroutetoaster with the mapmyride data and get very close. 10m difference each way but they also differ by 10m on the max height so that'll do for me. Love the interface on BRT much less cluttered than MMR! I think I'll be using that in the future.

Abs

 

[jimboalee]

http://streetmap.co.uk/

Have a look at your route on here using the 1:25,000 scale ( OS Pathfinder ).

http://streetmap.co.uk/map.srf?x=43...v=ratley&st=3&tl=Map+of+Ratley,+Warwickshire+[Town]&searchp=ids.srf&mapp=map.srf

Here's the terminus of my 'after work' 10 miler. Ratley, Warks. Well, the T junc at the top of Jacob's Ladder.
Notice the approach from the North has a single chevron. It is 18%.

If your 10 mile route hasn't got a chevron on it, your not looking hard enough

 

[HaloJ]

Cripes not even Alexandra Palace has a chevron on it and that's a killer of a hill for me never mind for him! I'm trying to get him out more not kill him!

 

[twentysix by twentyfive]

Cripes not even Alexandra Palace has a chevron on it and that's a killer of a hill for me never mind for him! I'm trying to get him out more not kill him!

Let us know how that's going after he's moved in for a while

 

[HaloJ]

Let us know how that's going after he's moved in for a while

touché