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  2. Geodetic coordinates - Wikipedia

    en.wikipedia.org/wiki/Geodetic_coordinates

    Geodetic latitude and geocentric latitude have different definitions. Geodetic latitude is defined as the angle between the equatorial plane and the surface normal at a point on the ellipsoid, whereas geocentric latitude is defined as the angle between the equatorial plane and a radial line connecting the centre of the ellipsoid to a point on the surface (see figure).

  3. Mercator projection - Wikipedia

    en.wikipedia.org/wiki/Mercator_projection

    With radius and great circle circumference equal to 6,371 km and 40,030 km respectively an RF of ⁠ 1 / 300M ⁠, for which R = 2.12 cm and W = 13.34 cm, implies that a ruler measurement of 3 mm. in any direction from a point on the equator corresponds to approximately 900 km. The corresponding distances for latitudes 20°, 40°, 60° and 80 ...

  4. Albers projection - Wikipedia

    en.wikipedia.org/wiki/Albers_projection

    Snyder [6] describes generating formulae for the projection, as well as the projection's characteristics. Coordinates from a spherical datum can be transformed into Albers equal-area conic projection coordinates with the following formulas, where is the radius, is the longitude, the reference longitude, the latitude, the reference latitude and and the standard parallels:

  5. Vincenty's formulae - Wikipedia

    en.wikipedia.org/wiki/Vincenty's_formulae

    Vincenty's formulae are two related iterative methods used in geodesy to calculate the distance between two points on the surface of a spheroid, developed by Thaddeus Vincenty (1975a). They are based on the assumption that the figure of the Earth is an oblate spheroid, and hence are more accurate than methods that assume a spherical Earth, such ...

  6. Map projection - Wikipedia

    en.wikipedia.org/wiki/Map_projection

    The special point or points may get stretched into a line or curve segment when projected. In that case, the point on the line or curve segment closest to the point being measured to must be used to measure the distance. Plate carrée: Distances from the two poles are preserved, in equatorial aspect.

  7. Miller cylindrical projection - Wikipedia

    en.wikipedia.org/wiki/Miller_cylindrical_projection

    where λ is the longitude from the central meridian of the projection, and φ is the latitude. [2] Meridians are thus about 0.733 the length of the equator. In GIS applications, this projection is known as: "ESRI:54003" [3] and "+proj=mill". [4] Compact Miller projection is similar to Miller but spacing between parallels stops growing after 55 ...

  8. Geographical distance - Wikipedia

    en.wikipedia.org/wiki/Geographical_distance

    View from the Swabian Jura to the Alps. Geographical distance or geodetic distance is the distance measured along the surface of the Earth, or the shortest arch length.. The formulae in this article calculate distances between points which are defined by geographical coordinates in terms of latitude and longitude.

  9. Cross-ratio - Wikipedia

    en.wikipedia.org/wiki/Cross-ratio

    The cross-ratio is a projective invariant in the sense that it is preserved by the projective transformations of a projective line. In particular, if four points lie on a straight line in then their cross-ratio is a well-defined quantity, because any choice of the origin and even of the scale on the line will yield the same value of the cross ...