How much ascending?!?

Recently Professor Badass received an email from a prospective entrant about how much climbing there actually was on the Bowland Badass. Apparently his friends were disbelieving about our headline figure of 18,500 feet ascent. Rather than try to convince them on this matter himself the Prof went downstairs at Badass Mansions to unlock the door to a dusty cell where we keep TechnicalExpert on trickle charge. He wiped down his circuit board with a damp cloth and entered the query. After a bit of whirring and banging, and the emission of a suspiciously foul odour from a rear vent, TechnicalExpert produced the following information bulletin:

There is often some discussion around the total ascent reported for ride routes, and the Bowland Badass is no exception. The difficulty stems from the way the various mapping software measures the ascent. Unfortunately, the most commonly used packages, the online route planners, are the most inaccurate, and it is to these that most people have ready access. It is probably true to say that the most accurate way to get a total ascent figure for any route would be to walk round it with a friend, a theodolite, and a stick! Let’s assume that none of us are going to do that! The second most accurate way is to go around the route with an accurate altimeter, with a high sampling rate (that is, a large number of measurements per second, or minute, or kilometre, or whatever). However, this too has potential for error, in that altimeters actually measure barometric pressure, and if this changes during the day, then inaccuracies creep in. However, to overcome this many altimeters can self calibrate when they are near known spot-heights. The third most accurate way is to plot, or load the route onto mapping software. Herein lie the greatest differences. The accuracy is dependent on three main factors. The algorithm used to do the calculation, the sampling rate (i.e. the number of measurements taken), and the resolution of the mapping. The better the algorithm, the higher the sampling rate, and the more accurate the mapping, the better will be the answer. Mapping software using the two main online mapping sources, Google Maps and Bing, are the least accurate. Those based on mapping such as Ordnance survey, are the most accurate. This most likely stems from the fact that the original expectation underlying mapping such as Google maps was that they would be used as 2 dimensional resources, for satnav and the like, and the third dimension, i.e. the one important to this discussion, was of low priority.

 To take an extreme example, consider an ascent from a point 500m above sea level, to a point 1000m above sea level. Assume that part way up, there is a descent of 100 metres. If there are only two sampling points, say at the top and bottom of the climb, the ascent will appear to be 500 metres. However, in reality, the total ascent is 600m. A third sampling point would pick that up. Some real life numbers:

Bowland Badass Fred Whitton
Plotted on Quo (uses O.S. maps) 5703 m 3980 m
Plotted on MMR (Google Maps and Tele-atlas data) 3100 m 2428 m
Plotted on Bikeroutetoaster (Google maps) 4200 m 3000 m
Ridden by TechnicalExpert, Garmin Edge 800 data 5600 m 4035 m

The Ordnance survey based mapping ascent correlates well with that measured on rides. There are many threads on the various on-line cycling discussions, and the conclusions there are the same.

We trust this fulsome treatise will satisfy the doubtful and the curious on this topic. If, however, you were lost on the 3rd sentence then do not worry. We, and all of our 2012 Badasses can assure you that there is plenty of ascent to go around on the Bowland Badass. At the end of it your leg muscles will feel like the pounded pulp of a million pilchards’ guts ground down beneath the tiny jackboots of an army of relentless Nazi hamsters on their wheels. You will suffer, yes, S-U-F-F-E-R. In the meantime here is a photograph of TechnicalExpert’s brain that the Professor took when he was upgrading the hard drive a few years back.

TechnicalExpert’s Brain

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Posted on November 27, 2012, in News and tagged , , , , . Bookmark the permalink. 1 Comment.

  1. Oooh that was good.. We have a word for technical experts like that …special
    But uv outdone yourself this time.
    Your very very Special.

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