Abstract : IGPS (Interactive Graphics Plotting System) is a computer-graphics program which produces high-quality plots of two-dimensional data; it is written in BASIC for the Tektronix 4051 desk-top computer. IGPS features: A large variety of axis systems, including probability paper for several distributions, logarithmic paper, and user-definable paper; neat tick mark and axis labeling with automatic or user-controlled decimal-point selection; several curve marker and dashed line types; legends; curve fitting; plotting of user-defined functions; data storage and retrieval on all Tektronix 4051 peripherals; and storage and retrieval of entire plots.