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The definition of time and different time systems
Published in Lucien Wald, Fundamentals of Solar Radiation, 2021
Geographic coordinates Φ and λ are associated with a geodetic system, which is a mathematical expression aimed at getting as close as possible to the gravity field of the Earth. The most widely used geodetic system in the world today is the World Geodetic System 84 (WGS84). It is the basis of the Global Positioning System (GPS) frequently used to know the geographic coordinates of a place. This geodetic system differs from the sphere since it takes into account in particular the flattening at the poles. This is why the geocentric and geographic coordinates differ. The difference must be accounted for when calculating the angles defining the position of the sun relative to a ground observer.
Geographic data in R
Published in Robin Lovelace, Jakub Nowosad, Jannes Muenchow, Geocomputation with R, 2019
Robin Lovelace, Jakub Nowosad, Jannes Muenchow
Geographic coordinate systems identify any location on the Earth’s surface using two values — longitude and latitude. Longitude is location in the East-West direction in angular distance from the Prime Meridian plane. Latitude is angular distance North or South of the equatorial plane. Distances in geographic CRSs are therefore not measured in meters. This has important consequences, as demonstrated in Section 6.
The angular characteristics of Moon-based Earth observations
Published in International Journal of Digital Earth, 2020
Huadong Guo, Yuanzhen Ren, Guang Liu, Hanlin Ye
To account for parameters related to the Earth’s surface, it is necessary to use the international terrestrial reference system (ITRS). Analogously, the principal axis lunar reference system (PALRS) is utilized for parameters related to the lunar surface (Archinal et al. 2011). Coordinates of latitude and longitude use the geographic coordinate system (GCS) and selenographic coordinate system (SCS).