In cases where D/B exceeds 2: 1, the formula contains the length of the shorter side of the reference field B instead of D. A graphic representation of the formula is depicted in figure (it is also contained in EN 12193 "Light and lighting – Sports lighting"). The corresponding minimum number M of measuring points towards the longer side of the reference surface is determined by the next higher whole odd number of the ratio M = D/P. The minimum number of measuring points towards the shorter side of the reference surface results from the next higher whole number N = M · B/D, B representing the length of the shorter side of the reference surface. EN 12193 specifies particular measuring grids for sports facilities, e.g. tracks. Accordingly, reference surfaces and number of grid points in both directions of the reference surface are specified for various sports. Example: Measuring field 20 m x 30 m. Image results in a point distance of P= 2,16 and M ≥ D/P = 14 for D = 30 m. The next odd number is 15. N is calculated as N ≥ M · B/D = 15 · 20 m / 30 m = 10. The next odd number is 11. The distances of the measuring points is D/M = 30/15 = 2 m towards the longer side of the reference field and B/N = 20/11= 1,8 m in the other direction.
