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They settled on five themes: location, place, relationships within places (later changed to human-environment interaction), relationships between places (later shortened to movement), and region. [4] The themes were not a "new geography" but rather a conceptual structure for organizing information about geography. [1]
The history of longitude describes the centuries-long effort by astronomers, cartographers and navigators to discover a means of determining the longitude of any given place on Earth. The measurement of longitude is important to both cartography and navigation. In particular, for safe ocean navigation, knowledge of both latitude and longitude ...
When time at the prime meridian (or another starting point) is accurately known, celestial navigation can determine longitude, and the more accurately latitude and time are known, the more accurate the longitude determination. The angular speed of the Earth is latitude-dependent. At the poles, or latitude 90°, the rotation velocity of the ...
v. t. e. 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.
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).
Figure 1. This BLM map depicts the principal meridians and baselines used for surveying states (colored) in the PLSS. The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.
Graticule (cartography) A graticule (from Latin crāticula 'grill/grating'), on a map, is a graphical depiction of a coordinate system as a grid of lines, each line representing a constant coordinate value. [ 1 ] It is thus a form of isoline, and is commonly found on maps of many kinds, at scales from local to global.
The map projection and the Geographic coordinate system (GCS, latitude and longitude) date to the Hellenistic period, proliferating during the Enlightenment Era of the 18th century. However, their use as the basis for specifying precise locations, rather than latitude and longitude, is a 20th century innovation.