Mapscale issues for orienteering maps

Map scales for orientering maps have been discussed frequently, and during the last years there seems to have been an increase in this activity.

The WOC in Finland 2001 has been heavily critizised for the very poor legibility of the competition maps, particularly the maps for the classic distances. As a result of this, many voices have been raised critizising the use of 1:15000 as the standard scale for classic orienteering. The ICOM at WOC2001 instead critizised the WOC maps for insufficient generalisation during surveying (in particular the excessive use of form lines). The WOC2001 practice is not in accordance with the current ISOM. It seems that the international controllers were not able to get this message through to the map makers, and the Finnish organisers seems to have been less than willing to persuade the WOC map makers into generalising to a level appropriate for classic orienteering (as specified in ISOM2000).

In the following I will try to point out some relevant issues regarding the choice of map scale for orienteering maps. At the bottom you will find some historical information regarding map scale.

The purpose of the orienteering map

Legibility and cognition

A classic orienteering course should test the skills of map reading and route choice. For map reading, the larger the map scale - the better (up to some limit). For route choice, there is a greater need for overview and an overall impression of the terrain, and therefore the longer the leg, the smaller the map scale should be in order to provide this overview.

In the early years of orienteering, the maps were very crude, so map reading was not that relevant, and route choice, instincts and luck were the deciding factors. As more and more detailed and accurate maps were made available, map reading became more and more important, and the need for larger map scales increased for legibility reasons. This shift occured around 1970, and the result of this was the 1:15000 map scale that was thought to be a good compromise between map reading and route choice.

In 1990, short distance orienteering (25 mins/4-5km) was introduced in the World Cup (and in 1991 in the WOC). Short distance orienteering contains very few long legs and the emphasis is therefore mostly on map reading. Consequently, one of the reasons for stopping the increase in map scale is not relevant for short distance orienteering. The size of the map is perhaps the most important limiting factor when deciding the map scale for short distance orienteering, and for a normal short distance course, the competition area fits well to the A4 (optimal?) paper size using a map scale of 1:10000.

In my opinion, the rationale behind the choice of 1:15000 as the best map scale for classic orienteering is still valid.

Since 1:10000 seems to be a good choice for short distance orienteering (and also for all courses that are of about the same length) and for old people that do not have the same eye sight as the average elite orienteer, the orienteering clubs have tended to favour 1:10000 when they produce maps.

Level of generalisation

Legibility requirements decide line widths and symbol sizes on the map. The map scale, symbol sizes and line widths combined with the requirements for legibility for an elite orienteer going at full speed through the (rough) forest limits the amount of detail on an orienteering map.

The task of the map maker is to choose what to include on the map, how to include it and what to leave out. This is generalisation in practice.

ISOM2000 says that terrain which cannot legibly be represented at 1:15000 scale is not suitable for international orienteering.

Map users

The users of orienteering maps fall into many categories. Examples: Competition orienteers at all leveles and of all ages (elite, beginner, junior, young, veteran), scouts, leisure orienteers, hikers, mushroom hunters, hunters, ...

The international specifications for orienteering maps (ISOM) has been made to address the needs of the competition orienteers in a world-wide sport. There is only one specification, and it is optimised for top level international elite orienteers competing in the World Orienteering Championships and World Cups all over the world. There are no separate specifications for veteran orienteers or beginners.

There does not seem to be a significant conflict between the different orienteering map users when it comes to the level of generalisation suitable for o-maps. If there is a tendency here, it would be that the elite orienteers will want much detail, while the others perhaps could do with less. Common to all users is the demand for sufficient legibility.

For non-competitive use of orienteering maps, the map is read in daylight while standing still. For competions, the map is read at speed in all light conditions by the best orienteers and while resting or walking by the others.

The map makers

When a map scale has been used for a number of years, the level of detail or the amount of detail on a map seem to be quite constant (for legibility reasons). The map makers want to make the map as accurate and detailed as possible, while keeping in mind the legibililty of the map. We have therefore seen a significant increase in the number of details on maps that are drawn for the 1:10000 scale since 1990. This trend is also affecting the 1:15000 maps, since the map makers have gotten used to putting on more detail when working on 1:10000 maps.

This trend might soon even threaten the legibility of the 1:10000 maps, possibly driving orienteering maps to even larger map scales.

In my opinion, it is now important to stop this trend by putting more emphasis on the map makers old art of generalisation.

We need to ask us some questions:

• Do we need more detail on our maps?
• What do we need this detail for?
• Will more detail on the maps make the runners able to complete an orienteering course faster and more confidently?
• Will more detail on the maps lead to a more fair competition?

The ISOM2000 says that maps in 1:10000 are enlargements of maps in 1:15000.

• No more objects
• Same level of generalisation
• The majority of screens retain 1:15000 specifications

How can we make the orienteering map makers follow the rules?

Map size

ISOM2000 says that the format of a competition map should not be larger than A3.

Price

Standard scales?

Should the choice of map scale be fully up to the map publisher? Is it a problem that a competition orienteer can get any mapscale (1:4000, 1:10000, 1:6500, 1:11000, 1:10500, 1:9000)?

Is it a part of the sport of orienteering to handle every possible map scale?

The opinions are different. My opinion is that the sport of orienteering offers quite enough challenges already, and that map scales should be standardised.

History

Important events

Conclusions

For classic orienteering the map scale of 1:15000 still seems to be a good compromise between the conflicting requirements of map reading during fine navigation and for route choice.

For shorter courses and short distance orienteering, larger map scales are normally preferred due to the greater emphasis on map reading for fine navigation. If a larger map scale is necessary to achieve an acceptable legibility, maps for these purposes should be strictly enlarged copies of the 1:15000 maps (an increase in the amount of detail on larger scale maps will push for even larger map scales).

What hinders the use of several scales is presently economy, but this might change when new and more flexible printing technology can compete with traditional offset printing.

Before allowing more detail to be introduced on orienteering maps, we should think carefully about the purpose of the sport of orienteering. What positive and negative consequences will more detailed orienteering maps have for the sport of orienteering?

Links

IOF Memo, Map scales for Foot Orienteering (1998)

ISOM2000