The construction first creates the perpendiculars of all the triangle sides;

The distance between two raster cells is the standard distance function applied to the locations of their respective midpoints; obviously the cell resolution has to be taken into account. Where a raster is used to represent line features as strings of cells through the raster, the length of a line feature is computed as the the sum of distances between consecutive cells.

Neighbourhood functions evaluate the characteristics of an area surrounding a feature’s location. A neighbourhood function “scans” the neighbourhood of the given feature(s), and performs a computation on it(them).