Yes you definitely should review the ISO spec, specifically section 8.3.3 "Common Transformations" and 8.3.4, "Transformation Matrices". For the six elements, a and b are the scale factors in X and Y positions of the movement in x, c and d are scale factors in X and Y positions of the movement in y, and h and v are absolute displacement in X and Y distances.
For example, applying the matrix [2 0 0 1 -10 10] at a current position of [10,10] would take you to [10,20] in the transformed system:
Xnew = (a * Xold) + (c * Yold) + h and Ynew = (b * Xold) + (d * Yold) + v
where: a = 2; b = 0; c = 0; d = 1; h = -10; v = 10; Xold = 10; Yold = 10
thus:
10 = (2 * 10) + (0 * 10) + (-10) and 20 = (0 * 10) + (1 * 10) + 10
JPellam (Datalogics)