Before revision: 250px|d = run Δh = rise l = slope length α = angle of inclination The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal.
After revision: stepth,250px|d = run Δh = rise l = slope length α = angle of inclination The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal.