Four-Point Method of Characteristics
Michael B. Abbott, Adrianus Verwey · Journal of the Hydraulics Division · 1970
Conservation laws in two independent variables have a four-point symmetry when expressed in normal or characteristic form. This symmetry is notated for nearly horizontal flows and translated into easily programmed numerical operators. Simple starting and boundary subroutines are described. The output is especially well adapted to digital-analog plotting techniques, with an accuracy superior to any current difference scheme. Bed slopes and resistance terms can be easily introduced, but the method becomes less viable for general stream flows, with changes of channel section.