Geographic coordinate system

A geographic coordinate system (GCS) is a spherical or geodetic coordinate system for measuring and communicating positions directly on Earth as latitude and longitude.^[1] It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface.^[2]

A full GCS specification, such as those listed in the EPSG and ISO 19111 standards, also includes a choice of geodetic datum (including an Earth ellipsoid), as different datums will yield different latitude and longitude values for the same location.^[3]

^ Chang, Kang-tsung (2016). Introduction to Geographic Information Systems (9th ed.). McGraw-Hill. p. 24. ISBN 978-1-259-92964-9.
^ DiBiase, David. "The Nature of Geographic Information". Archived from the original on 19 February 2024. Retrieved 18 February 2024.
^ "Using the EPSG geodetic parameter dataset, Guidance Note 7-1". EPSG Geodetic Parameter Dataset. Geomatic Solutions. Archived from the original on 15 December 2021. Retrieved 15 December 2021.

[chang2016-1] Chang, Kang-tsung (2016). Introduction to Geographic Information Systems (9th ed.). McGraw-Hill. p. 24. ISBN 978-1-259-92964-9.

[DiBiase-2] DiBiase, David. "The Nature of Geographic Information". Archived from the original on 19 February 2024. Retrieved 18 February 2024.

[epsg-3] "Using the EPSG geodetic parameter dataset, Guidance Note 7-1". EPSG Geodetic Parameter Dataset. Geomatic Solutions. Archived from the original on 15 December 2021. Retrieved 15 December 2021.

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