Meridians: Central meridian is a straight line. All other meridians are complex curves, spaced equally along the Equator and along each parallel and concave toward the central meridian.
Parallels: Equator is a straight line, poles are points, and all other parallels are nonconcentric circular arcs spaced at true distances along the central meridian. Each parallel has a curvature identical to its curvature on a cone tangent at that latitude. Many cones are involved; hence, the name "Polyconic projection."
Symmetry: About the central meridian and the Equator