Glossary

An Orienteering Course

Most orienteering courses are of the point-to-point variety, with a start, a series of controls to be visited in a designated order, and a finish. Usually the orienteer does not see the map and the course until after starting. However, at small local ev ents the map may be familiar, and orienteers may copy their courses from a master map before starting. There are usually several courses available at a meet, ranging from Course 1 (a short beginners’ course) through Course 8 (a long experts’ course).

This is an example of a beginners’ course. It has four controls, which must be visited in the order in which they are connected and numbered – though the orienteer is not constrained to following the lines (it’s easier to go out of your way a bit to use a trail). With the course comes a clue sheet, describing the exact location of the control flag within the circle on the map.

The clue sheet for this course is:

COURSE 1
3.5 km 75 m climb
Start: Corner of the field

CONTROL DESCRIPTION
1 BL trail junction
2 JC stream junction
3 PG SW corner of the evergreens
4 MP SW end of the knoll
5 BL upper part of the reentrant
Finish: NE corner of the building (350 m)

The clues define:

  • The number of the controls (as shown on the map)
  • The control code (usually two letters) that will be attached to the flag that is at the correct location
  • A description of the control feature, including (where appropriate) the part of the feature where the flag is hung.

Because verbal descriptions can be somewhat variable as well as specific to the language of the event organizer, advanced orienteers use a system of symbols to define the clues. Clue symbols are related to but not identical to map symbols, and the international clue symbol system is well worth learning once an orienteer progresses beyond the advanced beginner stage.

What is a “Reentrant”? 

Apart from a few geologists, only orienteers regularly use the English word “re-entrant” (or reentrant) to describe a landform.

A reentrant appears on the map as a U or V shape in the contour lines, pointing back into a hillside rather than sticking out of the hill (as would a spur). So a reentrant is a small valley, the centre of which would collect water and funnel it downhill (if it were raining hard). This portion of a map includes several reentrants, three of which are circled. The westernmost is a small, v-shaped reentrant, while the two eastern examples are broad and somewhat shallow.

Compass Types

Good compasses have a fluid-filled housing; the fluid dampens the motion of the needle, so that you can use the compass without holding it perfectly still. Avoid inexpensive compasses that do not have fluid-filled housings.

The compass needle is painted in two colors. Assuming that the compass is held flat, the red end points to north, and the white end to south. An interesting detail is that there are northern- and southern-hemisphere compasses. This has to do with the f act that the magnetic field lines, to which a compass needle aligns, point into the earth at the north and south magnetic poles. In the northern hemisphere the north end of the needle is pulled downwards, and the south end is counterweighted to balance t he needle. When you use a northern hemisphere compass in, say, Australia, the south end of the magnet is pulled downwards by the magnetic field, and is also heavier than the north end – resulting in a needle that catches and drags on the bottom of the compass housin g when the compass is held horizontal

A good compass will last a long time. However, some things can go wrong with a compass: the plastic components can break, or the housing can develop a leak. Over time, the fluid within the housing may turn an opaque blue-green. And, very rarely, the magnetization of the compass needle may reverse, so that the south end now points to north.

Baseplate or protractor compass

Thumb compass

Using a compass for orienting the map

Taking a bearing

How important is the compass?

The baseplate or protractor compass

This type of compass was invented by the Kjellstrom brothers during the World War II era and consists of a rectangular baseplate, which is marked with a red arrow pointing along the long axis, and a rotating compass housing marked in degrees (360 degrees for the full circle in most of the world, but 400 on some European compasses). Marked on the floor of the rotating compass housing are an arrow and a set of lines parallel to that arrow. Additional features may include a lanyard for attaching the compa ss to the wrist, scale bars for measuring map distances along one or more edges of the baseplate, a magnifying glass for reading fine map detail, and templates of a circle and triangle for marking orienteering courses on the map.

The thumb compass

In the mid 1980s, a top Swedish orienteer developed an alternative to the baseplate compass by reshaping the baseplate and adding a strap for attaching the compass to his thumb. This compass is then placed on the thumb of the left hand, which holds it on the map. The advantage of this system is that the map and compass are always read as a unit, the map is aligned more easily and quickly, plus one hand is left free; the disadvantage is that running very accurately on a bearing is more difficult. Personal preference usually determines the type of compass that is used; world championships have been won using both types.

Using a compass for orienting the map

This is a simple skill, and is probably the most important use of the compass:

Hold your map horizontally
Place the compass flat on the map
Rotate the map until the “north lines” on the map (a series of evenly spaced parallel lines drawn across the map, all pointing to magnetic north) are aligned with the compass needle
The map should now be oriented to the terrain. This makes it much easier to read, just as text is easier to read right side up than upside down.

Taking a bearing

Every direction can be expressed as an angle with respect to north. In the military and the boy scouts, this is called an “azimuth”, and bearings are expressed as a number of degrees. Orienteers take the easy way out, just setting the angle on their compass and keeping the needle aligned, which in turn keeps them going in the right direction. A simple set of step-by-step instructions for setting a bearing on a baseplate compass are:

  • Place the compass on the map so that the direction of travel arrow is lined up with the way you want to go
  • Turn the compass housing so that the arrows engraved in its plastic base are parallel to the north arrows drawn on the map (make sure the arrowhead points north and not south)
  • Take the compass off the map and hold it in front of you so that the direction of travel arrow points directly ahead of you
  • Rotate your body until the compass needle is aligned with the arrow on the base of the compass housing
  • Pick out a prominent object ahead of you along the direction of travel, go to it, and repeat the process (this way you can detour around obstructions but still stay on your bearing)

How important is the compass?

The most important navigational aid used in orienteering is the human brain. One other navigational device is in allowed and in general use: the compass. Compasses are useful for taking bearings and for orienting the map so that it is aligned with the terrain – but it is possible, in most areas, to complete a course quite easily and efficiently without a compass (an exception: it would be difficult to navigate flat areas poor in prominent features without a compass).

The compass is the only legal navigational aid that can be used in orienteering. Altimeters are specifically prohibited and GPS units are implicitly prohibited by the rules. It has been stated that GPS units could be very useful and helpful aids, but wh en the question of how an everyday orienteer would use a GPS unit to defeat the reigning US champion in a race was raised, the only valid reply was: “I would wait at the first control for him, use the GPS unit to knock him out, and then proceed on to victory”. Technology, however powerful, is no match for basic navigational ability – even in the hands of a good orienteer who is also a technological wizard. Beginning orienteers should learn basic compass skills and work on mastering map reading.

The Map

Although it is possible to orienteer on almost any map, it is much more enjoyable to use maps made specifically for orienteering. Such maps are accurate and detailed, and are prepared on a human scale – terrain and features are mapped so that what appear s on the map are the features that a human, moving through the area, sees readily. For example, boulders that are waist high appear on orienteering maps.
The orienteering map has evolved substantially over the last 50 years. In the 1940s, events in Scandinavia used 1:100,000 (1 cm =1 km) government issue maps, often in black and white and without contour lines to show the shape of the land. Nowadays, most orienteering events are held on five-color maps that have 5 meter contour intervals (16.5 feet) and have a scale of 1:15,000 (preferred) or 1:10,000 (1 cm = 100 meters).

Most of the characteristics of orienteering maps are related to those found on hiking and general use maps produced by the government. However, one feature of orienteering maps is specific to the sport: the north lines. On the example shown here, they are drawn in blue (on many maps, they are black). North lines are parallel lines drawn running from magnetic south to magnetic north, and are spaced 500 meters apart on the map. Why aren’t north lines on orienteering maps drawn pointing to true north? Because the angle between magnetic north and true north (the declination) varies widely in different parts of the world, and because orienteers use compasses to orient themselves (to magnetic north, not true north), it has become the standard to provide a series of reference lines on the map so that it is easy to use an orienteering compass to take a bearing.

There are international specifications for map symbols, and these have been successful in their aim of making orienteering map symbols standard throughout the world.

Some general rules for orienteering map symbols that make the system easier to understand

Orienteering Map Symbols

  • Black is used for rock features (for example, boulders, cliffs, stony ground) and for linear features such as roads, trails and fences as well as for other man-ma de features (for example, ruins and buildings)
  • Brown is used for landforms such as contour lines, small knolls, ditches, earthbanks.
  • Blue is used for water features: lakes, ponds, rivers, streams, marshes.
  • Yellow shows vegetation – specifically for open or unforested land. The density of the yellow colour shows how clear the area is: brightest yellow for lawns, pale yellow for meadows with high grass.
  • Green is used to show vegetation that slows down the passage of an orienteer. The darkest green areas, called “fight”, are almost impassably overgrown.
  • White on an orienteering map signifies forest with little or no undergrowth – forest that an orienteer can run through.
  • Purple (or red) is used to mark the orienteering course on a map. Conditions that are specific to an event (such as out-of-bounds fields in which crops are growing) are also designated in red or purple.

Orienteering Map Symbols

Landforms

Water

Linear

Other Man Made Features

Vegetation

How do you know you’ve found the control?

The control flag marks the spot that is circled on the map. It is made of fabric hung on a triangular box-kite-like wire frame. Each of the three square cloth faces is made up of a white upper triangle and an orange lower triangle. In North America, th e flag is usually hung from a branch or piece of deadwood near the control site, while in Europe the flag is usually hung from a wooden framework or metal stake stuck in the ground.

Attached to or near the control flag are one or more punches and a card with the “control code”. Each flag is assigned a unique control code, usually a two-letter combination (numbers may also be used, but international rules state that numbers 1-40 are not used for control codes). These codes allow the orienteer to determine that the control is in fact the correct one. The codes are usually listed in the clues that define the controls for each course, and many orienteers write the control codes in the corresponding boxes of the control card, to help make sure that they never punch at the wrong control or in the wrong box of the punch card.

How do they tell if you visited the control?

Mounted or hung near each control flag is a punch. An orienteering punch is a bright red plastic device with a number of sharp metal teeth. The orienteer uses this punch to impress the pattern made by the teeth onto a control card, in the box corresponding to the control being visited. When a control is expected to receive many visitors, as when a control is used by several different courses, several punches, all with the same pattern, are used.

    

At the finish line, the orienteer hands the card to the organizers, who verify that the punch patterns correspond to the correct controls.

The Control Card

Control cards can take various forms, but all include numbered boxes for punching in at successive controls as well as spaces (not shown here) for the name of the competitor, the course and class, the start time, the finish time, and the elapsed time. Fo r most orienteering events, starts are staggered so that no two people on the same course start at the same time. The intention is that each individual do their own navigation; following others is prohibited by the rules.
The World Orienteering Championships and many national championships are based on one race. However, nationally sanctioned North American orienteering events usually take the form of two separate races on two separate days (often on separate maps) with t he fastest two-day total time determining the winner, and the world’s largest event, Sweden’s O-Ringen, is a five-day event with the winner being determined by total time. Most events include a variety of courses ranging from the beginner level (easy nav igation, about 3 km) to the top category (difficult, about 10 km). Larger events will also have different classes for males and females, as well as for different age groups.

The standard orienteering event is a point-to-point race; controls are numbered on the map and connected in the order the competitor is to visit them. Upon reaching each control, the orienteer punches a pattern in the corresponding numbered box on the control card. This allows the event organizers to verify that the correct controls were visited. Sometimes an orienteer accidentally punches in the wrong box on the card; if this happens, the correct procedure is to punch in the cor rect box, and/or to punch in any of the boxes on the card that would not normally be used (for example, #20 could be used if the course has 12 controls) until punching in the correct box can be resumed (and it never hurts to explain what you did to someone at the finish line).

This control card was used in North America. If it had been used in Sweden, where events are large and rules are more tightly enforced, the orienteer would probably have been disqualified – because two of the punches, #2 and #8, are not entirely within t he box on the control card.

Route Choice in Orienteering

Navigation in orienteering can be reduced to two factors:

  • choosing one of the many possible routes to the control
  • finding your way along that route

Once you have learned some basic techniques and rules of navigation, it should always be possible to find the control – given that the map is accurate. Therefore, much of the variation among individuals’ times may come from their choice of routes. This is particularly true when speed through the terrain varies dramatically in different places, which can occur for any number of reasons:

  • a trail is faster than the woods
  • vegetation mapped as green may be very slow going
  • going uphill and then down may be slower than going the long way around
  • a potentially faster route may offer no navigational aids, while a longer/slower route provides a navigationally easy approach to the control site.

Another factor is that each individual may have particular strengths; one may run very fast on a trail, but slow down dramatically in the forest; another may have no great turn of speed, but chug away steadily uphill; still another may have no confidence in her ability to follow a compass bearing, but may be able to read contours very well. The best route for a beginner may not be the best route for an advanced orienteer.
Hence the choice of a route on a given leg between controls may have many possible “best” solutions. But, in turn, the true best solution may not be immediately apparent to orienteers who don’t plan carefully.

As an example, the map shown here gives the route choices and variations taken by the top orienteers at the Swedish National Championships some years ago (recall that there are about as many Swedish orienteers as all other countries combined). Each orienteer’s route is shown as a single red line, and at places where several individuals went the same way, red numbers show how many orienteers followed that portion of the route. Some fields (yellow) were out of bounds because crops were growing and are marked with red cross-hatching.

Although this is perhaps an extreme example, it does show the variety of routes (and combinations of subsets of routes) that may be possible on a single leg.