Map

A map is a simplified depiction of a space, a navigational aid which highlights relations between objects within that space. Most usually a map is a two-dimensional, geometrically accurate representation of a three-dimensional space. The science and art of map-making is cartography.

Scale and accuracy

Many but not all maps are drawn to a scale, allowing the reader to infer the actual sizes of, and distances between, depicted objects. A larger scale shows more detail, thus requiring a larger map to show the same area. For example, maps designed for the hiker are often scaled at the ratio 1:24,000, meaning that 1 of any unit of measurement on the map corresponds to 24,000 of that same unit in reality; while maps designed for the motorist are often scaled at 1:250,000. Maps which use some quality other than physical area to determine relative size are called cartograms.

Related Topics:
Scale - Ratio - Cartograms

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A famous example of a map without scale is the London Underground map, which best fulfils its purpose by being less physically accurate and more visually communicative to the hurried glance of the commuter. This is not a cartogram (since there is no consistent measure of distance) but a topological map that also depicts approximate bearings. The simple maps shown on some directional road signs are further examples of this kind.

Related Topics:
London Underground map - Topological - Road signs

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In fact, most commercial navigational maps, such as road maps and town plans, sacrifice an amount of accuracy in scale to deliver a greater visual usefulness to its user, for example by exaggerating the width of roads. With the end-user similarly in mind, cartographers will censor the content of the space depicted by a map in order provide a useful tool to that user.

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For example, a road map may or may not show railroads, and if it does, it may show them less clearly than highways.

Related Topics:
Railroads - Highways

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