1. A method for trimming geographic data that defines polygons to boundaries of a quadrangle, comprising: converting the geographic data into map coordinates in a modified azimuthal map projection, a map coordinate in the modified azimuthal map projection describing a projected point having an azimuthal angle proportional to longitude of the point, and having a radius from the center of the modified azimuthal map projection proportional to both longitude and latitude of the point such that parallels in the modified azimuthal map projection are projected as squares, the modified azimuthal map projection being non-equidistant; trimming one or more polygons along a lower longitude limit of the quadrangle in the modified azimuthal map projection; trimming one or more polygons along an upper longitude limit of the quadrangle in the modified azimuthal map projection; and converting the map coordinates in the modified azimuthal map projection back to geographic data.