the radar scan converter system receives range and azimuth data generated by a conventional radar as presented in a polar coordinate system , stores this data in associated cell locations in a range / azimuth polar video map , and displays this polar coordinate range / azimuth data in a cartesian coordinate system , in real time , on a conventional computer monitor having a rectangular display formed by a relatively large number of pixels organized in the cartesian coordinate system . each pixel in the display is sequentially update by selecting a respective pixel address , determining the corresponding range / azimuth cell address in the polar video map , reading the video level in this corresponding range / azimuth cell , and in response to this associated video level , either initially loading or subsequently updating the selected pixel . the radar scan converter system displays shades of gray or color , which may represent one or more video levels , and has an image decay capability over repeated radar scans which is particularly suited for display of a moving target .