* Cartesian grid 900 x 900 pixels, red lines at 100 pixel intervals, yellow lines at intermediate 50 pixels.  Width and height including labeling is 940 pixels.
This cartesian grid is designed for temporarily overlaying on images on which feature marker overlays are to be overlayed to allow a quick reckoning of the marker overlays' left and top coordinates.
Own work
User:Pee Tern