Map standards · IOF ISOM 2017-2

One map language, all over the world: ISOM

A runner in Sweden reads an orienteering map drawn in Ankara exactly as we do. The map specifications of the International Orienteering Federation (IOF) make that possible. This page sums up what ISOM says, why sprint maps are different and how maps are approved in Turkey.

Short answer: ISOM (International Specification for Orienteering Maps) is the IOF’s international technical specification for forest orienteering maps. The current version is ISOM 2017-2 Revision 6, mandatory since 1 January 2025. The base scale is 1:15,000 and the contour interval 5 m; the map uses about a hundred symbols in seven categories and seven main colours. Sprint maps have their own specification, ISSprOM 2019-2.

Based on ISOM 2017-2 Rev. 6 (January 2024), ISSprOM 2019-2 and the IOF Competition Rules 2026. Last updated: 28 September 2026.

What is ISOM and why does it exist?

In the early days, orienteers raced on small-scale state topographic maps, sometimes as small as 1:100,000. Special orienteering maps appeared in the 1950s, but every country used its own symbols. Fair international competition needed a standard, and the first official ISOM was published in 1969. In 1972 green was introduced to show runnability, and orienteering maps began to look much as they do today.

ISOM’s guiding principle is legibility: the map is read while running, in the shade of a forest, in the rain. So the specification asks the mapper to draw the terrain not “as it is” but generalised in the way that serves the runner. The aim is that results are decided by navigation skill, not by faults on the map.

A short history

1969The first official ISOM is published.
1972Green is introduced to show runnability.
1990sDigital cartography: maps move from pen and ink to the computer.
2000ISOM 2000 is published and stays in force for 17 years.
2017ISOM 2017 updates the rules for the age of LiDAR, GNSS and digital printing.
2018–2019ISOM 2017-2: 411 “impassable vegetation” removed, 532 “stairway” added.
January 2024Revision 6: new symbols (105.2, 203.2, 715), line-width and screen corrections. Mandatory since 1 January 2025.
2026–2030ISOM 2030 is in preparation; first draft in autumn 2026.

Not one standard but a family

ISOM is the basis of all the other specifications. Sprint, mountain-bike and ski orienteering depart from it through their own specifications.

Specification	Discipline	Scale	Contour interval	Version
ISOM 2017-2	Forest orienteering (middle, long, relay)	1:15,000; enlarged 1:10,000	5 m (2.5 m in flat terrain)	Rev. 6 · mandatory 1 Jan 2025
ISSprOM 2019-2	Sprint: parks, campuses, towns	1:4,000; enlarged 1:3,000	2 m or 2.5 m (5 m in steep areas)	Valid from 15 Jan 2022 · Rev. 2024
ISMTBOM 2022	Mountain bike orienteering (MTBO)	Base 1:15,000; 1:10,000, 1:7,500; sprint 1:5,000	5 m (10 m / 2.5 m)	January 2022
ISSkiOM 2019	Ski orienteering (Ski-O)	Long 1:15,000; middle and relay 1:10,000; sprint 1:5,000	5 m (2.5 m / 10 m)	1 Nov 2019
—	Trail orienteering (Trail-O)	Normally 1:4,000 or 1:3,000	Per ISSprOM / ISOM	No separate specification; Trail-O Rules 2026

Seven colours, one meaning each

In ISOM every colour has a single job. If you know the colour rule, you can start reading a map even before you recognise the symbols.

Brown
Landforms: contours, earth banks, knolls, pits, gullies.
101 104
Symbols
101–115
Print (CMYK)
25 · 75 · 100 · 0
Black and grey
Rock and everything man-made: cliffs, boulders, roads, paths, buildings, walls and fences.
202 505
Symbols
201–215 · 501–532
Print (CMYK)
0 · 0 · 0 · 100
Blue
Water: lakes, ponds, streams, marshes, springs, fountains.
304 308
Symbols
301–313
Print (CMYK)
100 · 0 · 0 · 0
Yellow
Open land: meadows, fields, treeless slopes. Full yellow is fully open; lighter screens are rough or scattered-tree land.
401 402
Symbols
401–404
Print (CMYK)
0 · 27 · 79 · 0
White
Runnable forest (405). White is not empty space; it is open forest you can run through at normal speed.
405
Symbols
405
Print (CMYK)
—
Green
How vegetation slows you: the darker the green, the slower. Green 30% slow running, 60% walk, 100% fight.
406 410
Symbols
406–419
Print (CMYK)
80 · 0 · 100 · 0
Purple
The course: start triangle, control circles, finish double circle, course lines, out-of-bounds areas.
703 706
Symbols
701–715
Print (CMYK)
35 · 85 · 0 · 0
Olive green
Area that shall not be entered (520): private gardens, yards, industrial sites. Yellow 100% plus green 50%. Entering means disqualification.
520
Symbols
520
Print (CMYK)
38 · 27 · 100 · 0

Swatches are approximate screen colours. CMYK values are from the IOF Printing and Colour Definitions, Rev. 4 (2024).

Runnability: the language of green

ISOM groups vegetation into five classes by the runner’s speed. Reference: a runner doing 4 min/km in flat, open forest.

Class	Speed	Pace (min/km)	On the map	Examples
1 · Easy running	> 100%	< 4	401Yellow, paved area, paths	Lawns, tarmac, paths
2 · Normal running	80–100%	< 5	405White (405)	Open forest, rough open land
3 · Slow running	60–80%	5–6:40	406Green 30% (406)	Dense vegetation, undergrowth
4 · Walk	20–60%	6:40–20	408Green 60% (408)	Dense trees and thickets
5 · Fight	< 20%	> 20	410Green 100% (410)	Barely passable vegetation

White stripes left inside a green screen show that the vegetation is easier to pass in one direction. Where stony ground and green combine, speed is lower than either alone.

Scale, enlargement and contour interval

Base scale 1:15,000

All forest maps are generalised for 1:15,000. A 1:10,000 map is not drawn separately: the 1:15,000 map is enlarged to 150%, and every line, symbol and screen grows in proportion.

Who gets enlargements?

1:10,000 is always recommended for the youngest age groups. For older age groups, where fine lines become harder to read, enlarged maps are recommended in every format.

Map size

Maps larger than A3 are avoided; maps cut to fit a course are no smaller than A5. Cut maps still show scale, contour interval and north.

Contour interval 5 m

Standardised so steepness is easy to judge. In flat terrain with slopes under 5%, 2.5 m may be used; two intervals are never mixed on one map.

Form lines sparingly

A form line between contours makes the ground look nearly twice as steep, so it is used only for important landforms that contours cannot show.

Scales at IOF events (Competition Rules 2026, rule 15)

Event type	Long	Middle and relay	Sprint
WOC, World Cup etc.	1:15,000	1:10,000	1:4,000
World Ranking Event (WRE)	1:15,000 (1:10,000 if approved)	1:10,000 (1:7,500 if approved)	1:4,000 (1:3,000 if approved)
Masters (WMOC)	1:10,000 or 1:7,500	1:10,000 or 1:7,500	1:4,000 or 1:3,000

At WMOC, 1:5,000 may be used for M/W80 and older with the IOF Event Adviser’s approval. The Turkish Orienteering Federation’s general competition rules (2019) set 1:4,000/1:5,000 for sprint, 1:7,500/1:10,000 for middle and relay, and 1:10,000/1:15,000 for long.

Generalisation and legibility

The mapper has four tools: selection (what goes on the map), simplification, displacement and exaggeration. The rule is clear: legibility always comes before absolute accuracy.

0.15 mm: Minimum gap between two symbols (2.25 m at 1:15,000).
0.4 mm: Minimum width of a passage between impassable features such as buildings (6 m).; 521
0.6 mm: Minimum drawn length of a cliff (202), 9 m. 0.9 mm when enlarged to 1:10,000.; 202
0.25 mm: Minimum width of 100% green (3.75 m); 0.3 mm for 100% yellow, 0.4 mm for screens.
20 mm: Spacing of magnetic north lines: 300 m at 1:15,000; 30 mm on an enlarged 1:10,000 map.; 601
2 items: Mandatory on the front of the map: scale and contour interval.

Accuracy is also judged from the runner’s point of view: a competitor using compass and pacing must perceive no discrepancy between map and ground. Relative height differences between neighbouring features matter more than absolute height. Maps should be georeferenced, but rotated to magnetic north before printing so the north lines run parallel to the paper edges.

Printing

Since 2024 the IOF recommends CMYK printing; at major IOF events 1:15,000 long-distance maps print brown as a separate spot colour (CMYK+B). Sprint, MTBO and ski-O maps are laser printed at 150 LPI or more. Course purple is placed below black, brown and blue so the detail underneath stays visible.

Why are sprint maps different?

ISSprOM’s key difference from ISOM: on a sprint map, thick black lines are used only for uncrossable features. In sprint, crossing them is not “hard” but forbidden.

Forbidden to cross or enter in sprint (Competition Rules 2026, rule 17.2)

520
520Area that shall not be entered (olive green): private gardens, flower beds, railway areas
521
521Building
515 518
515 · 518Uncrossable wall, uncrossable fence or railing (thick black line)
201 301 307
201 · 301 · 307Uncrossable cliff, body of water and marsh
411
411Uncrossable vegetation (dark green)
512.1
512.1Bridge or tunnel entrance (pass underneath only)
529
529Prominent uncrossable line feature
708 709 714
708 · 709 · 714Out-of-bounds boundary and area; temporary construction or closed area

Sprint symbols: IOF ISSprOM 2019-2 (© IOF, CC BY-ND 4.0), unaltered.

Forest maps differ: only 520 (area that shall not be entered), 708 and 709 (out of bounds) and 711 (out-of-bounds route) are forbidden. A cliff or fence drawn as “impassable” in ISOM is not forbidden; it tells you it is dangerous or too difficult for the average elite orienteer.

520

708

709

711

Forest symbols: ISOM 2017-2.

A sprint map may show at most two running levels (for example above and below a bridge), only one of them in detail. The IOF has separate guidelines for complex urban structures (2022) and “Best practices for sprint mapping” (May 2025).

ISOM 2017-2 symbol catalogue

All 113 numbered symbols in Revision 6, including sub-numbers. Turkish names follow the Turkish Orienteering Federation’s ISOM 2017 translation; symbols added later were translated by the club.

Search symbols (number or name)

113 symbols

No	Turkish	English	Type
Landforms 101–115 · brown
101	Eşyükselti eğrisi	Contour	Line
102	Gösterge eşyükseltisi	Index contour	Line, Text
103	Şekil çizgisi (yardımcı eğri)	Form line	Line
104	Toprak set (yar)	Earth bank	Line
105.1	Toprak duvar	Earth wall	Line
105.2	İstinat toprak duvarı	Retaining earth wall	Line
106	Çökmüş toprak duvar	Ruined earth wall	Line
107	Erozyon çukuru (yarıntı)	Erosion gully	Line
108	Küçük erozyon çukuru	Small erosion gully	Line
109	Küçük tepecik	Small knoll	Point
110	Küçük uzun tepecik	Small elongated knoll	Point
111	Küçük çukur (çöküntü)	Small depression	Point
112	Çukur	Pit	Point
113	Kırıklı arazi	Broken ground	Area
114	Çok kırıklı arazi	Very broken ground	Area
115	Belirgin yer şekli öğesi	Prominent landform feature	Point
Rock and boulders 201–215 · black + grey
201	Geçilemez sarp kayalık (uçurum)	Impassable cliff	Line
202	Sarp kayalık	Cliff	Line
203.1	Kayalık çukur veya mağara	Rocky pit or cave	Point
203.2	Tehlikeli çukur	Dangerous pit	Point
204	Kaya kütlesi	Boulder	Point
205	Büyük kaya kütlesi	Large boulder	Point
206	Devasa kaya kütlesi veya kaya sütunu	Gigantic boulder or rock pillar	Area
207	Kümelenmiş kaya kütlesi	Boulder cluster	Point
208	Kaya parçası alanı	Boulder field	Area
209	Yoğun kayalık alan	Dense boulder field	Area
210	Taşlık zemin, yavaş koşu	Stony ground, slow running	Area
211	Taşlık zemin, yürüyüş	Stony ground, walk	Area
212	Taşlık zemin, mücadele	Stony ground, fight	Area
213	Kumlu zemin	Sandy ground	Area
214	Çıplak kaya	Bare rock	Area
215	Hendek	Trench	Line
Water and marsh 301–313 · blue
301	Geçilemeyen su kütlesi	Uncrossable body of water	Area
302	Sığ su kütlesi	Shallow body of water	Area
303	Su çukuru	Waterhole	Point
304	Geçilebilir su yolu	Crossable watercourse	Line
305	Küçük geçilebilir su yolu	Small crossable watercourse	Line
306	Ufak / mevsimsel su kanalı	Minor/seasonal water channel	Line
307	Geçilemeyen bataklık	Uncrossable marsh	Area
308	Bataklık	Marsh	Area
309	Dar bataklık	Narrow marsh	Line
310	Belirsiz bataklık	Indistinct marsh	Area
311	Kuyu, çeşme veya su tankı	Well, fountain or water tank	Point
312	Kaynak	Spring	Point
313	Belirgin su öğesi	Prominent water feature	Point
Vegetation 401–419 · green + yellow
401	Açık alan	Open land	Area
402	Dağınık ağaçlı açık alan	Open land with scattered trees	Area
403	Engebeli açık alan	Rough open land	Area
404	Dağınık ağaçlı engebeli açık alan	Rough open land with scattered trees	Area
405	Orman	Forest	Area
406	Bitki örtüsü, yavaş koşu	Vegetation: slow running	Area
407	Bitki örtüsü, yavaş koşu, iyi görüş	Vegetation: slow running, good visibility	Area
408	Bitki örtüsü, yürüyüş	Vegetation: walk	Area
409	Bitki örtüsü, yürüyüş, iyi görüş	Vegetation: walk, good visibility	Area
410	Bitki örtüsü, geçilmesi zor (mücadele)	Vegetation: fight	Area
412	Ekili alan	Cultivated land	Area
413	Meyve bahçesi	Orchard	Area
414	Bağ veya benzeri	Vineyard or similar	Area
415	Belirgin ekili alan sınırı	Distinct cultivation boundary	Line
416	Belirgin bitki örtüsü sınırı	Distinct vegetation boundary	Line
417	Belirgin büyük ağaç	Prominent large tree	Point
418	Belirgin çalı veya ağaç	Prominent bush or tree	Point
419	Belirgin bitki örtüsü öğesi	Prominent vegetation feature	Point
Man-made features 501–532 · black
501	Kaplı alan	Paved area	Area
502	Geniş yol	Wide road	Line
503	Yol	Road	Line
504	Araç izi	Vehicle track	Line
505	Yaya yolu / patika	Footpath	Line
506	Küçük patika	Small footpath	Line
507	Belirsiz küçük patika	Less distinct small footpath	Line
508	Dar orman yolu veya doğrusal iz	Narrow ride or linear trace through the terrain	Line
509	Demiryolu	Railway	Line
510	Elektrik hattı, teleferik veya telesiyej	Power line, cableway or skilift	Line, Point
511	Ana elektrik hattı	Major power line	Line, Point
512	Köprü / tünel	Bridge / tunnel	Line, Point
513.1	Duvar	Wall	Line
513.2	İstinat duvarı	Retaining wall	Line
514	Harabe duvar	Ruined wall	Line
515	Geçilemez duvar	Impassable wall	Line
516	Çit	Fence	Line
517	Harabe çit	Ruined fence	Line
518	Geçilemez çit	Impassable fence	Line
519	Geçiş noktası	Crossing point	Point
520	Girilemez alan	Area that shall not be entered	Area
521	Yapı / bina	Building	Area
522	Kanopi (sundurma)	Canopy	Area
523	Harabe	Ruin	Line
524	Yüksek kule	High tower	Point
525	Küçük kule	Small tower	Point
526	Taş yığını	Cairn	Point
527	Hayvan yemliği	Fodder rack	Point
528	Belirgin çizgisel öğe	Prominent line feature	Line
529	Belirgin geçilemez çizgisel öğe	Prominent uncrossable line feature	Line
530	Belirgin insan yapımı öğe – halka	Prominent man-made feature – ring	Point
531	Belirgin insan yapımı öğe – x	Prominent man-made feature – x	Point
532	Merdiven	Stairway	Line
Technical symbols 601–603 · black + blue
601	Manyetik kuzey çizgisi	Magnetic north line	Line
602	Referans (çakıştırma) işareti	Registration mark	Point
603	Yükseklik noktası	Spot height	Point, Text
Course planning 701–715 · purple
701	Çıkış (start)	Start	Point
702	Harita alma noktası	Map issue point	Point
703	Hedef (kontrol noktası)	Control point	Point
704	Hedef sıra numarası	Control number	Text
705	Parkur çizgisi	Course line	Line
706	Bitiş (finiş)	Finish	Point
707	İşaretli rota	Marked route	Line
708	Sınır dışı alan sınırı	Out-of-bounds boundary	Line
709	Sınır dışı alan	Out-of-bounds area	Area
710	Geçiş noktası	Crossing point	Line
711	Sınır dışı rota	Out-of-bounds route	Line
712	İlk yardım noktası	First aid post	Point
713	İçecek noktası	Refreshment point	Point
715	Harita değişimi sonrası devam noktası	Continuing point after map exchange	Point

Symbol images are reproduced unaltered from IOF ISOM 2017-2 Revision 6 (© IOF, CC BY-ND 4.0). Red figures are drawing dimensions in millimetres at the 1:15,000 print scale; the blue “min.” box shows the smallest permitted form, and the red arrow marks symbols that must be oriented to north. Number 411 was removed in 2018; 714 exists only in the sprint specification. orienteering.sport/iof/mapping

Map approval and mapping in Turkey

In Turkey, orienteering maps are the responsibility of the Map Committee of the Turkish Orienteering Federation (TOF), made up of a Map Acceptance Commission and a Course Planning and Controllers Commission.

Registration

New maps are checked in OCAD format and in the field against ISOM / ISSprOM. A map scoring 90 or more on a 100-point checklist is accepted. Unregistered maps cannot be used at official races or permitted private races.

Event approval

Maps for permitted private races are sent to TOF in OCAD format at least 20 days before the event; without Map Committee approval the event cannot take place.

Mapper grades

Grade 1 (assistant mapper): town, park and school areas that need no contours. Grade 2: any terrain (one year’s experience, five accepted sprint maps, an 80-hour course). Grade 3: expert mapper.

Courses

TOF runs grade 1 mapping courses in Ankara (Pursaklar, January 2023; Ümitköy, January 2025). Announcements are published on the federation’s website.

This is a summary; TOF’s regulations in force are binding.

Map quality control at the IOF

The IOF reviews the maps of major events at the desk, following the method the Swedish federation has used since 2014. The map file goes to the Map Commission at least six months before the event; area and line symbol sizes are checked with OCAD tools, symbol shapes against a standard map, and form-line use and spacing by eye. The check takes about 1–1.5 hours and results in a list of errors and improvements.

WMOC 2028: The IOF’s preliminary 2028 programme includes the World Masters Orienteering Championships in Turkey (WMOC, 27 October – 3 November 2028). Those maps too will go through this check by April 2028.

Coming next: ISOM 2030 and ISSprOM 2031

2030

ISOM 2030

In September 2024 the IOF Map Commission launched a comprehensive revision of ISOM. The focus is not new symbols but colours and the graphical appearance of the map: making use of better printing technology, improving legibility especially for runners with colour vision deficiencies, and countering ever more detailed maps with symbol definitions that support better generalisation. Federations’ suggestions closed on 30 September 2025; the first draft is planned for autumn 2026. All other specifications will then be based on ISOM 2030.

2031

ISSprOM 2031

In a letter dated 15 September 2026 the IOF announced the revision of the sprint specification. It will focus on colours, graphical appearance, symbol parameters and complex urban terrain, with new symbols where they aid generalisation and legibility. Suggestions can be sent until 30 August 2027, approved by the national federation.

Period	Stage
09/2026 – 08/2027	Call for proposals
09/2027 – 05/2028	Working and reference group work
06/2028 – 01/2029	First draft
08/2029 – 09/2029	Final draft and presentation
10/2029 – 11/2029	Approval
02/2030	Publication
01/2031	In force

Have an idea for sprint maps? Write to us; as a club we will collect suggestions and pass them on through TOF.

Send your idea

Mapping tools

OCAD

Swiss commercial software and the de facto standard for orienteering mapping. TOF reviews maps for registration in OCAD format. Includes LiDAR and digital elevation model tools.

ocad.com/en/orienteering

OpenOrienteering Mapper

Free and open source. Runs on Windows, macOS, Linux and Android, with ISOM 2017-2, ISSprOM, ISMTBOM and ISSkiOM symbol sets. The Android version lets you draw on a tablet in the field.

openorienteering.org/apps/mapper

Purple Pen

Free course-setting software; works with OCAD and Mapper maps and generates control descriptions automatically.

purplepen.golde.org

Karttapullautin

Free tool that turns a LiDAR point cloud into a base map with contours, cliffs and vegetation.

github.com/grst/karttapullautin

Kanyon and maps

Kanyon Orienteering makes its own maps. Our park, campus, forest and school-ground maps are based on the standards on this page. Contact us about a map for your organisation or school, or for guidance if you want to start mapping.

For organisations For schools Contact

Frequently asked questions

What is ISOM?

ISOM (International Specification for Orienteering Maps) is the International Orienteering Federation’s technical specification for forest orienteering maps. It defines which features are shown and with which symbols, colours and dimensions. The current version is ISOM 2017-2 Revision 6, mandatory since 1 January 2025.

What does white mean on an orienteering map?

White is open forest that can be run through at normal speed (ISOM 405). Beginners often take white for empty space; treeless open land is actually yellow, and vegetation that slows you down is green.

What scale are orienteering maps?

The base scale of forest maps is 1:15,000, used for long-distance races. For middle-distance and relay races the map is enlarged to 1:10,000. Sprint maps are 1:4,000, or 1:3,000 when enlarged.

How is a sprint map different from a forest map?

Sprint maps (ISSprOM) are 1:4,000 with a 2–2.5 m contour interval and show urban detail more richly. The key difference is that thick black lines are used only for uncrossable features, and crossing them is forbidden.

What happens if I enter an olive-green or purple-hatched area?

Olive green (520) marks areas that shall not be entered and purple hatching (709) out-of-bounds areas. Under the IOF Competition Rules a competitor who enters them can be disqualified. These are often private property or protected nature.

Who approves orienteering maps in Turkey?

The Map Committee of the Turkish Orienteering Federation (TOF). Maps are checked in OCAD format and in the field against ISOM / ISSprOM; a map scoring 90 or more on a 100-point checklist is registered. Unregistered maps cannot be used at official races.

How can I learn to draw orienteering maps?

Start with a school ground or park map in the free OpenOrienteering Mapper. TOF’s grade 1 mapping courses qualify you for park, town and school maps that need no contours. Kanyon Orienteering’s mappers are happy to help beginners.

When will the next version of ISOM appear?

The IOF Map Commission is working on ISOM 2030; the first draft is planned for autumn 2026. The focus is not new symbols but colours, graphical appearance and legibility for runners with colour vision deficiencies. The new sprint specification, ISSprOM 2031, will come into force in January 2031.