Mx and my in EFDC model

I was wondering how EFDC model reads the metric coefficient mx and my. IN cartesian coordinates the values of mx and my are equal to 1. However, in curvilinear coordinates, they have some finite values. Are these values read from lxly.inp ? lxly.inp file provides the cell center coordinates and components of a rotation matrix. Is the rotation matrix the same as mx and my ?



Hi John, we assume you are referring to the equations 2 & 3 on page 7 of the “Theoretical and Computational Documents.” As these partial differential equations can’t be solved directly, EFDC uses a finite difference approach. This means that the scale factor mx and my are simply referring to dx and dy for each of the cells.