Abstract: A kind of Gauss projection based on the equidistant sphere is studied by reason of the problem of the impracticality of calculation by using the spherical coordinates for the traditional Gauss projection based on the horizontal elliptic cylinder. First, the direct and inverse solutions of the Gauss projection based on the equidistant sphere are derived by using the direct and inverse solutions of the rectifying latitude with respect to the geodetic latitude, which help to calculate the distortions of meridians and parallels. Then, the length distortion, angular distortion, area distortion, and convergence of meridians of the Gauss projection based on the equidistant sphere are analyzed. Finally, in comparison with the traditional Gauss projection as regards these distortion parameters, the Gauss projection based on the equidistant sphere is available in practice.

Key words: Gauss projection, equidistant sphere, rectifying latitude, length distortion, convergence of meridians