ICES statistical rectangles have been in use since the 1970's, and were first officially referenced in CM document 1977/Gen:3 document 'ICES Statistical Rectangle Coding System'.
ICES statistical rectangles provide a grid covering the area between 36°N and 85°30'N and 44°W and 68°30'E.
Latitudinal rows, with intervals of 30', are numbered (two-digits) from 01 at the southern boundary (latitude 36°00'N) and increasing northwards to 99. The northern boundary of the statistical rectangle system is, thus, latitude 85°30'N.
Longitudinal columns, with intervals of 1°, are coded according to an alphanumeric system, beginning with A0 at the western boundary (longitude 44°00'W), continuing A1, A2, A3 to longitude 40°W. East of 40°W, the coding continues B0, B1, B2, ..., B9, C0, C1, C2, ..., C9, etc., using a different letter for each 10° block, to the eastern boundary of the area covered. Note that the letter I is omitted. Thus:
When designating an ICES rectangle, the northern coordinate is stated first. Thus, the rectangle of which the south-west corner is 54°00'N 03°00'E is designated 37F3.
Usually, it is necessary to specify an area with more precision than is possible with a statistical rectangle designation. Therefore, a sub-rectangle designation must be given (as a fifth character) by dividing a statistical rectangle into nine (10' latitude x 20' longitude) sub-divisions, as follows:
A location 58°12'N 10°33'E would lie within ICES rectangle/sub-division 45G05