Image 3A simulated history of Earth's day length, depicting a resonant-stabilizing event throughout the Precambrian era (from Earth's rotation)
Image 4The definition of latitude (φ) and longitude (λ) on an ellipsoid of revolution (or spheroid). The graticule spacing is 10 degrees. The latitude is defined as the angle between the normal to the ellipsoid and the equatorial plane. (from Geodesy)
Image 22A plumb bob determines the local vertical direction (from Gravity of Earth)
Image 23Initial acquisition of GPS signal in 2D (from Geodesy)
Image 24Earth's gravity measured by NASA
GRACE mission, showing deviations from the
theoretical gravity of an idealized, smooth Earth, the so-called
Earth ellipsoid. Red shows the areas where gravity is stronger than the smooth, standard value, and blue reveals areas where gravity is weaker. (Animated version.) (from Gravity of Earth)
Image 26Mapping can be done with
GPS and
laser rangefinder directly in the field. Image shows mapping of forest structure (position of trees, dead wood and canopy). (from Cartography)
Image 29On a
prograde planet like Earth, the stellar day is shorter than the
solar day. At time 1, the Sun and a certain distant star are both overhead. At time 2, the planet has rotated 360 degrees and the distant star is overhead again but the Sun is not (1→2 = one stellar day). It is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). (from Earth's rotation)
Image 31A medieval depiction of the
Ecumene (1482, Johannes Schnitzer, engraver), constructed after the coordinates in Ptolemy's
Geography and using his second map projection. The translation into Latin and dissemination of Geography in Europe, in the beginning of the 15th century, marked the rebirth of scientific cartography, after more than a millennium of stagnation. (from Cartography)
Image 32Global plate tectonic movement using GPS (from Geodesy)
Image 33The cartographic process (from Cartography)
Image 34Height measurement using satellite altimetry (from Geodesy)
Image 35Deviation of day length from SI-based day (from Earth's rotation)
Image 37A pre-Mercator nautical chart of 1571, from Portuguese cartographer
Fernão Vaz Dourado (
c. 1520 – c. 1580). It belongs to the so-called plane chart model, where observed latitudes and magnetic directions are plotted directly into the plane, with a constant scale, as if the Earth were a plane (Portuguese National Archives of Torre do Tombo, Lisbon). (from Cartography)
Image 38Global
gravity anomaly animation over oceans from the NASA's GRACE (Gravity Recovery and Climate Experiment) (from Geodesy)
Image 39A map of recent volcanic activity and ridge spreading. The areas where NASA GRACE measured gravity to be stronger than the theoretical gravity have a strong correlation with the positions of the volcanic activity and ridge spreading. (from Gravity of Earth)
Image 41Ellipsoid - a mathematical representation of the
Earth. When mapping in geodetic coordinates, a latitude circle forms a truncated cone. (from Geodesy)
Image 46Earth's
axial tilt is about 23.4°. It oscillates between 22.1° and 24.5° on a 41,000-year cycle and is currently decreasing. (from Earth's rotation)