Contour Counting

Contour Counting in Great Britain

The amount of climbing can be worked out by following the route of an event on an Ordnance Survey map, and counting the number of contour lines which it crosses. OS Landranger 1:50,000 maps are recommended. In some areas where contour lines are tightly packed, or where there is a lot of detail obscuring them, 1:25000 maps are better.

1:50,000 OS maps have contour lines at 10 metre intervals. 1:25000 OS maps can have contour lines at 10 metre intervals or 5 metre intervals. I find a magnifying glass essential with paper based maps, but other people have better eyesight than me. Computer mapping software such as Memory-Map or a website such as bikehike are excellent for contour counting because you can zoom in close and get an accurate count.

Count contour lines for the whole event (or event section), and not just the main climbs. The amount of climbing in the intervening flatter parts can add up to a substantial amount over the course of an event, and so increase the total climbing and the AAA points score. Contour counting of the major climbs only and working out climbing based on spot heights at the bottom and top of major climbs are not recommended for this reason.

Count contour lines when the route is both ascending and descending. The formula for converting from contour lines to climbing and AAA points assumes that both have been counted. The advice used to be to count every single contour line which the route crosses, and this is still the general case. Include a contour line which disappears under the road for some time before emerging again on either side of the road, but count it as one only.

However, experience has shown that this can sometimes lead to an overstated climbing figure, and in some situations contour lines should be ignored:

• When crossing a river bridge and contour lines run along the river banks. The bridge is likely to be flat(tish) and above river bank level.
• When crossing the top of a narrow hillside valley. The road is likely to be built up across the very tip of the valley, so the same comment applies as for crossing a river bridge.
• When the route repeatedly crosses contour lines all of the same height, without others of different heights intervening. Count the first contour line, then ignore any repeats for the next few hundred metres. This is especially the case when the route goes through a flat area.

Beware that 1:50,000 maps can omit contour lines where the slope is steep. This is particularly noticeable in Wales. You may need to add in extra lines to your total to compensate.

If the event or event section starts and finishes at different locations and heights, make a note of the start and finish heights.

Excel Contour Count Spreadsheet

An Excel Contour Counter spreadsheet is available to help with contour counting. It contains some notes on how to use it, the results from a sample event, and two blank worksheets for you to use. To download the spreadsheet, click here.

To calculate Climbing

To calculate the climbing by hand instead of using the contour count spreadsheet, do the following:

• Count the number of contour lines crossed by the route as above.
• Divide the number of contour lines counted by two.
• Multiply the result by 10 for maps with 10m contour or 5 for maps with 5m contour lines.

If the start and finish points are at different heights, then this figure needs to be adjusted:

• If the finish is higher than the start, then add HALF the difference in height between the finish and the start. For example for a finish at 200m and a start at 100m, then add ½ (200 – 100), i.e. 50m
• If the finish is lower than the start, then subtract HALF the difference in height between the finish and the start. For example for a finish at 200m and the start at 300m, then subtract ½ (300 – 200), i.e. 50m.

These adjustments may sound odd but are correct. Adjustment methods published previously in AUK literature are not correct and should not be used.

Round the result to the nearest 250 metres of climbing.

Contour Counting in Other Countries

French maps, including IGN ones, and Spanish maps,and European maps available online, tend to have "artistic" rather than accurate contour lines, and counting them will not give an accurate climbing figure. The road up Alpe d'Huez for example, according to the contour lines, includes quite a lot of descent which certainly was not there when I last rode up it!

Despite the advice to the contrary above, the best way to "contour count" mountainous routes in the Alps, Pyrenees and Spanish Sierras is to base it on spot heights at the bottom and top of climbs, and any intermediate spot heights that are available, then add some on to cover sections between the major climbs and descents, say 1,000m per 100 km for gently rolling landscape.