Intersection algorithms for lines and circles

This paper presents a unified representation scheme for the implicit equations of points, lines, and circles. An associated set of geometric algorithms operates successfully on degenerate and nearly degenerate geometry, and when necessary produces degenerate geometric results. Computation errors are interpreted geometrically in order to establish preconditions for reliable results and requirements on the resolution of computer arithmetic. The algorithms thus provide a basis for the wide range of geometric constructions required by computer-aided drafting and design systems.