However, the adequacy of the approximation depends on the relationship of the sub-track track separation to the heights of the aircraft above. There may be situations (very tight or very dispersed tracks) where a different number of subtracks is more appropriate. Too few subtracks cause ‘fingers’ to appear in the contour. Tables C-1 and C-2 show the parameters for a subdivision into between 5 and 13 subtracks. Table C-1 shows the location of the particular subtracks, Table C-2 the corresponding percentage of movements on each subtrack.