This document is being developed for use of those working with Image Processors and GIS machines. ARC/INFO GIS absobloominglutely insists that the X-axis goes to the right and the Y-axis goes up, and the only way to change its mind is to turn the screen on its side and look from the back. Thus I will abandon the South African surveying tradition of having LOx pointing south and LOy pointing west. My X and Y axes will point the conventional mathematical way, to the east and north respectively. When you wish to compare with ye olde surveying types and with the little blue tics on the map, don't forget to swap X and Y and flip both with a minus sign.