Scale (map)
A map scale is the size of an object compared to the size of the object's smaller representative on a map.[1] This can be shown by a scale bar and a ratio 1:n. The reader can measure a distance on the map to know what is the distance on the ground.
People sometimes speak of a map as one with a "large scale" or "small scale". A "large scale" map makes things look large, and a "small scale" map makes things look small. For example, an island displayed on a 1:10,000 map will appear larger than if it were displayed on a 1:25,000 map. Thus, the former is "large scale". What can be confusing is that for a map of a given physical size, say 11 by 17 inches, a "large scale" map will have a smaller geographic extent than a "small scale" map centred on the same point.
Maps with a ratio of 1:50 000 or larger (for example, 1:40 000 would be larger) are considered large scale. Maps with a ratio of 1:50 000 to 1:250 000 are considered intermediate scale. Any maps with a smaller scale (for example 1:300 000) are considered small scale. [2]
Scale (map) Media
A graphical or bar scale. A map would also usually give its scale numerically ("1:50,000", for instance, means that one cm on the map represents 50,000cm of real space, which is 500 meters)
A bar scale with the nominal scale expressed as "1:600 000", meaning 1 cm on the map corresponds to 600,000 cm=6 km on the ground.[a]
The Winkel tripel projection with Tissot's indicatrix of deformation
This figure defines latitude and longitude on a sphere. Also shown is an element bounded by nearby meridians and parallels.
Infinitesimal elements on the sphere and a normal cylindrical projection
The equidistant projection with Tissot's indicatrix of deformation
The Mercator projection with Tissot's indicatrix of deformation. (The distortion increases without limit at higher latitudes)
Lambert's normal cylindrical equal-area projection with Tissot's indicatrix of deformation
Shows the meridian scale factor for three cylindrical projections: Mercator, Equirectangular, Lambert equal area. The Mercator scale factor is istropic so the parallel scale for Mercator is given by the same graph. Since all cylindrical projections have the same parallel scale factor this applies to the other two projections.
Scale variation near the equator for the tangent (red) and secant (green) Mercator projections.
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Related pages
References
- ↑ "map (cartography) :: Map scales and classifications -- Britannica Online Encyclopedia". britannica.com. Retrieved on 30 September 2010.
- ↑ 3 Ways of Showing a Map's Scale. https://www.thoughtco.com/map-scale-measuring-distance-on-map-1433533. Retrieved 2018-01-26.
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