Tetrad (unit Of Area)
A tetrad is an area 2 km x 2 km square. The term refers to any of the 25 such squares which make up a standard hectad A hectad is an area 10 km x 10 km square. The term has a particular use in connection with the British Ordnance Survey national grid, and then refers to any of the 100 such squares which make up a standard 100 km x 100 km myr .... Tetrads are sometimes used by biologists for reporting the distribution of species to maintain a degree of confidentiality about their data, though the system is not in universal use. The tetrads are labelled from ''A'' to ''Z'' (omitting ''O'') according to the "DINTY" system as shown in the grid below, which takes its name from the letters of the second line. References Units of area {{measurement-stub ...
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Hectad (unit Of Area)
A hectad is an area 10 km x 10 km square. The term has a particular use in connection with the British Ordnance Survey national grid, and then refers to any of the 100 such squares which make up a standard 100 km x 100 km myriad; these are denoted using the letter code of the 100 km square, and then a two-digit number consisting of the one-digit easting of the western bound of the hectad and the one-digit northing of its southern bound. See also * Tetrad (unit of area) A tetrad is an area 2 km x 2 km square. The term refers to any of the 25 such squares which make up a standard hectad. Tetrads are sometimes used by biologists for reporting the distribution of species to maintain a degree of confidentia ... Units of area {{measurement-stub ...
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