Key:ele

ele=* specifies elevation (height above sea level) of a point, in metres. This is mainly intended for mountain peaks but could also be used for elevation of airport runways and many other objects.

For OpenStreetMap, this value should be in metres above mean sea level as defined by the  EGM96 geoid model. This elevation is usually very close to the national "above sea level" systems with differences < 1m. This is not the height above the WGS84 ellipsoid (see  geoid how these differ), which is shown as raw elevation by some satellite navigation devices, and which can differ from geoid elevation by up to 100 m.

In case of buildings and other man_made=* structures that stand on the ground, tag the elevation of the surrounding ground, not of the structure itself (i.e. do not tag the elevation of the tip of a tower; instead, set ele=* to the elevation of the ground level, and add the height with the tag height=*).

Basics

Main article: Altitude

OSM currently records points with their latitude and longitude (x/y coordinates). Elevations are only recorded for features where they are significant, such as peaks or surveyed points. Where this is done, the elevation above geoid (EGM96) is stored in the ele=* key. OpenStreetMap does not try to be a general elevation database, so do not tag elevation of nodes with no other tags, as well as for objects whose elevation is not an information of general interest.

The elevation in a local datum can be tagged as ele:local=*, with elevation specified in metres. A proposed notation to store vertical datums other than the EGM96 is ele:xyz=*, where xyz is the map datum, and the value is specified in metres.

Sources for elevation values can be signs or values from literature. Such values should also be checked for plausibility since elevation signs and official mountain heights are known to be frequently inaccurate. Another source of elevation data are GPS traces, but elevation values from these are usually much less accurate than the horizontal position. You also need to make sure values are in the correct coordinate system, or converted as necessary in case of ellipsoid-based elevations.

Another source of elevation data are gridded elevation data sets. Those are often used in outdoor maps to render relief, like OpenCycleMap and Reit- und Wanderkarte, and elevation values can be determined from displaying these maps as a background layer in editors. Beware, however, that such data sets contain significant rounding errors, and discrepancies from accurate elevation values can easily be as much as 50 metres.

Elevation information with sub-metre accuracy is rarely verifiable, so the values should be specified in integer metres.

National reference systems

Elevations posted on official signs are usually relative to the national reference system of the respective country and have to be converted to WGS84/EGM96.

Country	Standard	Common name	Heights	Tide gauge	Reference point	Conversion
Australia	Australian Height Datum	Metres above mean sea level		32 distinct tidal references points on Australian coastline.	Ausgeoid09	Conversion calculator online
Austria		Meter über Adria (m ü. Adria) (metres above Adriatic)	Normal-orthometric	Trieste 1875	Hutbiegl
Belgium		meter boven Oostende Peil (m O.P.) (metres above Oostende tide gauge)	Orthometric	Ostende	Ostende
Czech Republic	Bpv (Baltic Sea vertical datum)	metrů nad mořem (m n.m.) (metres above sea level)	Normal (Molodenskii's)	Kronstadt	Kronstadt, Russia
Estonia	BK77		Normal	Kronstadt	Kronstadt	[2]
Finland	N43,N60,N2000		Orthometric	Helsinki	Helsinki	[3]
France (mainland)	NGF-IGN69	mètres au-dessus du niveau de la mer (m) (metres above sea level)	Normal	Marseille	Marseille	[4]
France (Corsica)	NGF-IGN78	mètres au-dessus du niveau de la mer (m) (metres above sea level)	Normal	Ajaccio	Ajaccio	[5]
Germany	DHHN2016	Meter über Normalhöhennull  Normalhöhennull	Normal	Amsterdam	Wallenhorst
Former West Germany </ref>	DHHN12	Meter über Normalnull	Normal-orthometric	Amsterdam	Hoppegarten (near Müncheberg)
Former East Germany	SNN76	Meter über Höhennull (m ü. HN)	Normal	Kronštadt	Hoppegarten (near Müncheberg)
Hungary		Tengerszint feletti magasság	Normal	Kronštadt	Nadap
Ireland		metres above sea level (m ASL / m a.s.l.)	Orthometric	Malin Head	Malin Head
Italy		metri sul livello del mare (m s.l.m.) (metres above sea level)	Orthometric	Genoa	Genoa
Japan		Tōkyō-wan heikin kaimen (東京湾平均海面) (Tokyo Peil, T.P.)	Orthometric	Chiyoda, Tokyo	Nihon suijin genten (日本水準原点), 24.3900m
Liechtenstein	LN02	Meter über Meer (m ü. M.) (metres above sea level)		Marseille	Geneva
Luxemburg			Orthometric	Amsterdam	Amsterdam
Netherlands		meter boven/onder NAP (m NAP) (metres above/under NAP)	Orthometric	Amsterdam	Amsterdam
Norway		meter over havet (moh.) (meters above sea level)	Normal-orthometric	Tregde	Tregde
Poland		metry nad poziomem morza (m n.p.m.)	Normal	Kronštadt
Portugal		Nível médio do mar adotado (NMA)	Orthometric	Cascais	Datum Altimétrico Nacional de 1938 (Cascais)
Russia	BS1977	высота (метры) над уровнем моря (elevation/metres above sea level)	Normal	Kronstadt	Kronstadt	The pseudo-geoid model EGM2008BALT is available for St. Petersburg / Kronstadt area [6]
Slovakia		metrov nad morom (m n.m.) (metres above sea level)	Normal	Kronštadt
Slovenia			Normal-orthometric	Trieste 1900	Ruse
Spain		metros sobre el nivel del mar (msnm) (metres above sea level)	Orthometric	Alicante	Alicante
Sweden	RH2000	Meter över havet (m ö.h.) (metres above sea level)	Normal	Amsterdam
Switzerland	LN02	Meter über Meer (m ü. M.) (meters above sea level)		Marseille	Geneva	Transformation and calculation services
Turkey			Normal-orthometric	Antalya	Antalya
UK - Great Britain	Ordnance Datum Newlyn	metres above sea level (m ASL / m a.s.l.)	Orthometric	Newlyn, 1915 to 1921	Newlyn	OSGM02, Coordinate transformer
UK - Northern Ireland	Belfast Ordnance Datum	metres above sea level (m ASL / m a.s.l.)	Orthometric	Clarendon Lock, Belfast, 1951 to 1956.	Clarendon Lock, Belfast
Former Yugoslavia		Nadmorska visina (m/nv, ~metres above Adriatic)	Normal-orthometric	Trieste 1875/1900

Example

The height of Breithorn in Switzerland is 4 164 metres. It could be mapped as:

natural=peak

name=Breithorn

ele=4164

The height of rail tracks in Tanggula railway station is 5 068 metres. It could be mapped as:

railway=station

name=唐古拉

name:bo=གདང་ལ་།

name:en=Tanggula

name:zh=唐古拉

ele=5068

Local units

It's been noted that some elevations are more conspicuous than others, and the requirement that key:ele be in metres is unhelpful for denotation on mountain peaks in non-metric areas. Since locals in the United States (and certainly elsewhere) think of things like mountain elevations strictly in feet, there seems to be no good way to address this with the current framework.

• It's tempting to enter an elevation with a unit of measure ("3045 feet") but the tag must be in metres
• Some software relies on this tag being numeric metres

There is likely no good solutions to this without using a separate tag for tagging height in local units. As of September 2021, ele:ft=* is used on over 2,300 features, while about 600 features are tagged with feet or inches in ele=*.

Features with variable elevation

Most terrain features have a constant elevation, meaning the ele tag is unambiguous. There are some exceptions, however, that can offer challenges when mapping elevation.

One example of this is a reservoir. When using the ele tag on a non-intermittent, ordinary lake, if usually refers to the elevation of the (close to constant) water level. Since reservoirs have water levels that change within certain bounds, it is unclear how one should interpret the ele tag when present on a reservoir, as it could be referring to the maximum water level, the minimum water level, or something in between. There is not yet an agreed upon scheme for making the meaning more clear, but some mappers use the following tags to add clarity to the situation:

• ele:min to denote the minimum water level achievable by regulation. Usually corresponds to the lowest point in the transition between a reservoir and a drainage tunnel/pipe.
• ele:max to denote the maximum water level achievable by regulation. Can correspond to the level of the spillway, or higher. Might need further refinement.
• ele:natural to denote the water level before the dam was built.

Possible Tagging Mistakes

elevation=*

More details at taginfo

• elevation=*

If you know places with this tag, verify if it could be tagged with another tag.
Automated edits are strongly discouraged unless you really know what you are doing!

altitude=*

More details at taginfo

• altitude=*

If you know places with this tag, verify if it could be tagged with another tag.
Automated edits are strongly discouraged unless you really know what you are doing!

See also

• layer=* - used to mark layering of map elements
• level=* - used to indicate the floor level where a feature is located in a building
• height=* - used to mark how tall a map object is
• alt=* - Proposal to mark exact altitudes concerning to the reference system of heights. Deprecated.
• man_made=survey_point
• ele:wgs84=* an explicit wgs84 elipsodial height
• ele:local=* unclear meaning
• Proposed_features/ele:regional - a proposal to tag ele in the regionally common system and units
• Proposed features/ele with units – a proposal to allow ele=* itself to be expressed in the local units