CVLGrid uses the Cartesian coordinate system to specify cell locations. The Cartesian coordinate system specifies a point on a plane relative to two perpendicular directed lines that split the cell into four quadrants. In CVLGrid "I" represents the index of cell along the X-axis and "J" represents the one along the Y-axis, in which X, Y is the curves in general. The base unit for this coordinate system is meters.
CVLGrid also allows the user to upload a shape file of the model domain. The base coordinate system used for these files is the Universal Transverse Mercator (UTM) with base units in meters as well.