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[26] [27] [page needed] The fraction R / a is called the representative fraction (RF) or the principal scale of the projection. For example, a Mercator map printed in a book might have an equatorial width of 13.4 cm corresponding to a globe radius of 2.13 cm and an RF of approximately 1 / 300M (M is used as an abbreviation for ...
A projected coordinate system – also called a projected coordinate reference system, planar coordinate system, or grid reference system – is a type of spatial reference system that represents locations on Earth using Cartesian coordinates (x, y) on a planar surface created by a particular map projection. [1]
The Mercator projection is now used on the vast majority of nautical charts. Since the Mercator projection is conformal, that is, bearings in the chart are identical to the corresponding angles in nature, courses plotted on the chart may be used directly as the course-to-steer at the helm.
Mercator Nova et Aucta Orbis Terrae Descriptio, 1569. High res image. Flemish geographer and cartographer Gerardus Mercator world map of 1569 introduced a cylindrical map projection that became the standard map projection known as the Mercator projection. It was a large planisphere measuring 202 by 124 cm (80 by 49 in), printed in eighteen ...
The Mercator projection shows rhumbs as straight lines. A rhumb is a course of constant bearing. Bearing is the compass direction of movement. A normal cylindrical projection is any projection in which meridians are mapped to equally spaced vertical lines and circles of latitude (parallels) are mapped to horizontal lines.
The projection from spheroid to a UTM zone is some parameterization of the transverse Mercator projection. The parameters vary by nation or region or mapping system. Most zones in UTM span 6 degrees of longitude, and each has a designated central meridian. The scale factor at the central meridian is specified to be 0.9996 of true scale for most ...
The Mercator projection of a world map. The angles are untrue for area, especially at high latitudes. Also note increasing distances between the latitudes towards the poles and the parallel lines of longitude. The only true world map is the globe. The Mercator projection comes from a globe inside a cylinder.
(That is, the reciprocal of the cosine of the latitude become infinite). He therefore uses a completely different projection for the inset map of the north polar regions: an azimuthal equidistant projection. It took many years for Mercator's projection to gain wider acceptance. The following gallery shows the first maps in which it was employed.