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S01E010 is a reference to a square in Tanzania. S means the square is south of equator, and E means it is East of the zero meridian. The numbers refer to longitudinal and latitudinal degree. A square with no sublevel reference is also called QDGC level 0. This is square based on a full degree longitude by a full degree latitude.
The third and fourth digits (xx00 through xx17) similarly indicate the number of tens of degrees of longitude of the 'minimum' square boundary, nearest to the Prime Meridian. By way of illustration, the square 1000 thus extends from 0°N to 10°N, 0°E to 10°E, and the square 7817 from 80°N to 90°N, 170°W to 180°W, adjacent to the major ...
The northern hemisphere covered by a 5×5 degree, equal angle, latitude-longitude grid. In c-squares notation, each cell of the grid has a unique identifier, incorporating the identity of its parent (10×10 degree) cell, and further divisible into 1-degree, 0.5-degree, 0.1-degree cells, etc., as fine as may be desired.
Other denotations include sq. deg. and (°) 2. Just as degrees are used to measure parts of a circle, square degrees are used to measure parts of a sphere. Analogous to one degree being equal to π / 180 radians, a square degree is equal to ( π / 180 ) 2 steradians (sr), or about 1 / 3283 sr or about 3.046 × 10 −4 sr.
On the Equator at sea level, one longitudinal second measures 30.92 m, a longitudinal minute is 1855 m and a longitudinal degree is 111.3 km. At 30° a longitudinal second is 26.76 m, at Greenwich (51°28′38″N) 19.22 m, and at 60° it is 15.42 m.
The elevation is the signed angle from the x-y reference plane to the radial line segment OP, where positive angles are designated as upward, towards the zenith reference. Elevation is 90 degrees (= π / 2 radians) minus inclination. Thus, if the inclination is 60 degrees (= π / 3 radians), then the elevation is 30 degrees ...
λ 0 is the longitude of the central meridian, φ 0 is the latitude chosen to be the origin along λ 0; φ 1 is the latitude whose parallel is chosen to have correct scale. To avoid division by zero, the formulas above are extended so that if φ = 0 then x = 2A and y = −φ 0. If φ 1 = 0 then A = 1 / 2 (λ − λ 0).
[2] Some cartographers have used the term "graticule" to refer not only to the visual lines, but to the system of latitude and longitude reference itself; [3] however, in the era of geographic information systems, it is more accurate to call this the geographic coordinate system.