Tetrad (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.[1]

Tetrads are sometimes used by biologists for reporting the distribution of species to maintain a degree of confidentiality about their data,[2] though the system is not in universal use.[1]

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.[1]

E J P U Z
D I N T Y
C H M S X
B G L R W
A F K Q V

References
  1. "DINTY Tetrads". Kent and Medway Biological Records Centre. Archived from the original on 27 May 2011. Retrieved 23 December 2008.
  2. "National Grid References". Sussex Biodiversity Record Centre. 2008. Retrieved 23 December 2008.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.