Spot elevation
A small cross with a number beside it is a spot elevation: the height of that point, in the map’s units. There is no survey mark on the ground, which is what sets it apart from a benchmark.
Easily confused with
- Benchmark symbolBM on a topographic map marks a benchmark: a permanent survey mark, often a metal tablet, whose elevation has been measured. The number beside it is that elevation.
- Mine symbol (crossed picks)Two crossed picks mark a quarry or open pit mine on a USGS topographic map. A Y shape on its side is a mine tunnel, a small half-filled square a mine shaft, and a single X a prospect.
How to read it
The USGS symbol sheet draws a spot elevation as a small cross with the elevation in italics beside it, separate from its control points and benchmarks. It gives a height between the Contour lines. Natural Resources Canada’s legend has spot elevations, and it prints precise elevations in black.
Also searched as: elevation number on a map, spot height, survey height, X with a number on a map.
These pages describe what each symbol on a map shows. They are not navigation instructions: the map’s own legend says what each of its symbols means, and symbols differ between map series and editions.
Differences by country
On Ordnance Survey maps, heights are to the nearest metre above mean sea level. Where two heights are shown together, the OS says, the first is the ground at the triangulation pillar and the second, in brackets, the highest natural point of the summit nearby.
Look-alikes
The same cross with BM in front of it is a Benchmark symbol, a point with a permanent survey mark.
Read next
- Next in Topographic map symbolsNorth arrows and declination diagramThe diagram of three lines in the margin of a USGS topographic map shows three different norths: true north (the star), grid north (GN) and magnetic north (MN, with a half arrowhead). The angles between them are the declination.
- The same shape in Greek lettersQuantum circuit gate symbols (H, X, CNOT, measurement)The symbols of a quantum circuit diagram: each horizontal line is a qubit, a box with a letter is a gate (H for Hadamard, X, Y, Z, S, T), a dot joined by a line to ⊕ is a controlled-NOT, and a box with a meter is a measurement.
More topographic map symbols
The same shape elsewhere
Browse symbols drawn with crosses or letters and numbers.
Sources
- Topographic Map Symbols, USGS General Information Product (first posted 2005), U.S. Geological Survey, Control data and monuments
- Toporama Legend, Edition 1.2, 2013 (after the NTS 1:50,000 standards and specifications), Natural Resources Canada, Legend
- Topographic Maps: The Basics, Centre for Topographic Information guide, Natural Resources Canada, What do the colours mean?
- OS Explorer map legend (1:25 000), Generic legend, version 2022-09, Ordnance Survey, Heights and natural features
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
Added .