MEASURING ORIENTEERING COURSE DISTANCE AND CLIMB

DISTANCE

Orienteering course lengths are measured straight line from control to control. This is a simple method that, while providing at least a relative measure of the distance actually travelled in Scandinavia, it tends to be quite misleading in the Bay Area. Our steep terrain and impenetrable vegetation often require major deviation from the bee-line route. However, the rules call for measuring the shortest distance taking into account only certain impassable features, taped routes (such as finish chutes) and out of bounds areas. Generally, lakes are circumvented with the ruler while "fight" areas are not. (Fight should be, but almost never is, distinguished form truly impenetrable vegetation). Marked (required) routes are measured along their actual alignment.

There are a variety of techniques of measurement available. If the map is in your computer you will be able to measure it precisely. The usual method is to use the good old ruler or scale and add up the measurements. I prefer the relatively low-tech method I learned in one of my college cartography classes many years ago. Essentially, the process is to tick off your points along the edge of a piece of paper and make an accurate measurement of the accumulated distance.

Here are some suggested steps:

1. Use a map of the course with accurately registered control circles (6mm is standard.) An enlargement may aid in accuracy (but be sure to include the graphic scale in the blow up.)

2. Check the graphic scale, even of the original map. Some bad goofs have been known to be made at the printing stage. If a photo copy, the scale is even more likely to be off

3. Use a sheet of paper, preferably long enough to cover the course on one edge. You can splice pieces with Scotch tape or use a strip of calculator paper for longer courses. Make your marks on the paper with a razor blade, exacto or sharp pencil.

4. Begin at the timing start. This may be different than the triangle, a point often overlooked in compiling course lengths. Personal knowledge of the course may be necessary for accurate measurements since the timing start, if different than the triangle, is usually not shown on course maps.

5. Make pin pricks at the actual start, the center of the start triangle, the center of the first control circle and the finish circles (if they have different diameters than that of the last control.)

6. Line up your paper wth the corner at the timing start and the edge through the center of the triangle or first control as appropriate. Make a mark on your paper corresponding with the center of the triangle or circle. If this is a required route and not a straight line, make adjustments as is necessary for all marked routes.

7. Mark your ticks on the paper as S, Triangle, 1,2,3..., F, etc. for later checking.

8. Between control circles align the paper through the centers but, with the previous mark on the right edge of the circle, make your mark on the right edge of the next circle. This avoids accumulating error in estimating the centers.

9. Occasionally check for the accuracy of the circle in relation to the control. For super accuracy, keep in mind that the line widths are (should be) .35mm.

10. Continue around the course accumulating the distance on your paper. Measure around certain uncrossable obstacles by marking the shortest possible route. The course map should show this. Follow marked routes, which may require a little judgement. If you must measure to the center of the finish circle, remember to use the center of the last control. The run-in is usually not a straight line.

11. Measure the length marked on the paper in mm. I usually use a long scale to reduce the number of measurements.

12. Convert to ground distance in kilometers by dividing by 100 for 1:10,000 maps and 66.7 for 1:15,000. Round to two decimal points.

13. A rougher method and one good as a double check is to use the compass scale. Take a reading for each leg as above and add them up. Round to one decimal point. This should be reproducible to within 100m. A good map measuring wheel is another reasonable way to double check very quickly.

14. Even if you do not have O-cad, if you have a digitizing board, you can get quick and very accurate figures with even a simple shareware CAD or drawing program.

15. When preparing specs for a meet, the course-setter should go through the process a second time, primarily to assure that major errors have not crept in. The vetter should confirm the accuracy.

============================================================

CLIMB

Climb is the height gain that would be encountered along a viable winning route.

1. Draw the optimum route for the course.

2. Count the contours crossed on the uphill beginning where timing begins (which includes any distance to the master maps or triangle.)

3. Record the number of contours for each leg for future checking.

4. Multiply the total number by the contour interval.

Things to remember:

HEIGHT LOSS Height loss is disregarded. (This is not always an insignificant factor as a course may have a large overall loss which may be combined with very little gain.)

OPTIMUM ROUTE The optimum route is the theoretical best route, not necessarily the winner's route. It is one that would be followed by a fit, aggressive runner. He/she is likely to run straighter and climb more than others.

If there is more than one route that is a viable choice for a potential winner, use the one with the most climb. The others, obviously have other limitations, such as distance which are NOT reflected in the stats. For example, in choosing between a leg involving a big climb vs. an equivalent long flat run (sign of a thoughtful design), in fairness, the climb of the shorter route should be included in the stats since the longer distance of the other cannot be.

READING BETWEEN THE LINES In Bay Area terrain, contouring often looks much better on the map than on the ground due to inaccurate and generalized contours, especially in steeper stream valleys. This means that the map often must be interpolated. The stats should reflect climb even if not shown on the map. Those missing contours in some of our big ravines ("re-entrants"?) as at Las Trampas and Briones should be figured in. On the other hand, it is usually accepted that minor ups and downs between contours do not figure in. Usually, the climb estimates should be reproducible to within two or three contours.

ACCURACY The advertised course stats should be pretty precise, particularly for "B" and higher events. Accuracy is important

a. to assure that the courses adhere to standards

b. to give the competitors a precise idea of what to expect

c. for evaluation of the course and performances afterwards (accuracy of the design time, min/k, etc.)

Simple methods should result in consistent accuracy. A rule of thumb for is that measurements should be reproducable within 2-3mm for distance (1-2%) and 2-3 contours on the map. The climb figures can be considerably more subjective due to map and terrain variables as well as the route factor.

-js

===========================================================