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  2. South-up map orientation - Wikipedia

    en.wikipedia.org/wiki/South-up_map_orientation

    The Tabula Rogeriana, drawn by al-Idrisi in 1154 The Blue Marble photograph in its original orientation [1]. South-up map orientation is the orientation of a map with south up, at the top of the map, amounting to a 180-degree rotation of the map from the standard convention of north-up.

  3. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    Earth's rotation axis moves with respect to the fixed stars (inertial space); the components of this motion are precession and nutation. It also moves with respect to Earth's crust; this is called polar motion. Precession is a rotation of Earth's rotation axis, caused primarily by external torques from the gravity of the Sun, Moon and other bodies.

  4. Map projection - Wikipedia

    en.wikipedia.org/wiki/Map_projection

    A medieval depiction of the Ecumene (1482, Johannes Schnitzer, engraver), constructed after the coordinates in Ptolemy's Geography and using his second map projection. In cartography, a map projection is any of a broad set of transformations employed to represent the curved two-dimensional surface of a globe on a plane.

  5. Direction determination - Wikipedia

    en.wikipedia.org/wiki/Direction_determination

    Direction determination refers to the ways in which a cardinal direction or compass point can be determined in navigation and wayfinding.The most direct method is using a compass (magnetic compass or gyrocompass), but indirect methods exist, based on the Sun path (unaided or by using a watch or sundial), the stars, and satellite navigation.

  6. Mercator projection - Wikipedia

    en.wikipedia.org/wiki/Mercator_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 1,000,000 in writing an RF) whereas Mercator's original 1569 map has a width of 198 cm corresponding to a globe radius of 31.5 cm and an ...

  7. Earth-centered, Earth-fixed coordinate system - Wikipedia

    en.wikipedia.org/wiki/Earth-centered,_Earth...

    The Earth-centered, Earth-fixed coordinate system (acronym ECEF), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.

  8. Circle of latitude - Wikipedia

    en.wikipedia.org/wiki/Circle_of_latitude

    There are five major circles of latitude, listed below from north to south. The position of the Equator is fixed (90 degrees from Earth's axis of rotation) but the latitudes of the other circles depend on the tilt of this axis relative to the plane of Earth's orbit, and so are not perfectly fixed. The values below are for 25 February 2025: [2]

  9. Earth-centered inertial - Wikipedia

    en.wikipedia.org/wiki/Earth-centered_inertial

    The x-axis is permanently fixed in a direction relative to the celestial sphere, which does not rotate as Earth does. The z-axis lies at a 90° angle to the equatorial plane and extends through the North Pole. Due to forces that the Sun and Moon exert, Earth's equatorial plane moves with respect to the celestial sphere.