1. A process for implementing a look-up table means in a digital computer in order to provide radar scan conversion for radar data based upon polar coordinates to radar data based upon rectangular coordinates wherein said look-up table means is addressed by signals that represent range and angle (r,.theta.) values from a radar receiver and supplies signals to a monitor display that represent (x,y) coordinate values that define pixel locations of said monitor display, comprising the steps of: (a) providing an inverse mapping of integral (x,y) coordinate values to integral (r,.theta.) coordinate values of an equivalent radar PPI display area in said look-up table means by calculating in said digital computer each (r,.theta.) coordinate value from said integral (x,y) coordinate values and by rounding-off each fractionally calculated (r,.theta.) coordinate value to the nearest (r,.theta.) integral coordinate value, and (b) providing a forward mapping of integral (r,.theta.) coordinate values of said equivalent radar PPI display which were not mapped by said inverse mapping to integral (x,y) coordinate values in said look-up table means by calculating in said digital computer each (x,y) coordinate value from said equivalent integral (r,.theta.) coordinate values that were not mapped by said inverse mapping, and by rounding-off each fractionally calculated (x,y) coordinate value to the nearest integral (x,y) coordinate value.