Abstract: A “Rendering Process and Method for Digital Map Illumination Intensity Shading” is disclosed that assigns an illumination intensity to pixels in a video display imaging a mapped terrain. The process comprises the steps of: providing a rectangular grid array of altitude values covering an area to be shaded. Each altitude value has a map position characterized by a coordinate location referenced to a first and second coordinate axes crossing orthogonally at an origin. Each coordinate location has a first and second value. Each first and second value characterizes the distance of the respective coordinate location from the origin. The map area is divided into an array of contiguous triangles. Each triangle area has a perimeter bounded by three straight line segments passing between three coordinate locations. The video display has pixel areas that corresponding to each respective triangle area. A normal vector is calculated for each triangle area.