Fast building of a matrix

The matrix of heights may be created in Fast building mode or in a usual mode. All elements  of  a matrix can be shared into two groups conditionally. Elements which values are defined at the initial stage of building according to map objects  concern to the first group. Elements which values are calculated with use of the nearest elements of the first group concern to the second group. The mode Fast building differs from a usual mode that search at calculation of the second group elements  is carried out in the field of the smaller size and by smaller quantity of directions. Values of  the  same elements of the second group, received at building in different modes, may differ a little.