10 DECEMBER 1988, Page 13

`...and statistics'

ON the Van der Grinten [map] projec- tion . . . the Soviet Union is 223 per cent larger than in reality. . . On the Robinson version, the Soviet Union is 18 per cent larger than in reality. . . On the Robinson projection, the 48 contiguous states of the United States are 3 per cent smaller than they really are; on Van der Grinten, they are 68 per cent larger.

(New York Times, 25 October).

The writer cannot really mean the projections are 'larger than' reality; no piece of paper would be big enough to fit them on. Such percentage differ- ences must relate to some arbitrary scale. But this is not given. The point of maps is to accommodate the surface of the oblate spheroid known as the Earth in two-dimensional form with the mini- mum distortion of any given tract of territory relative to all the others. In practice you can't make one bit (e.g., the Euro-Asian land mass) to scale without hopelessly distorting the others (e.g., Africa). Hence the problem. £20 goes to Marc Landis of New York.

Send examples to . . and statistics'; £20 for the best published; £10 for every other published. [180 sans the lbw].