[data structures]
In ArcGIS, a two-digit method to locate a pixel, or cell, within an image file using row and column referencing (x,y); x provides the column number (commonly starting from 0 at the left) and y provides the row number (commonly starting from 0 at the top).
[remote sensing]
In remote sensing, the coordinates in a physical sensor model originating at the principal point of the sensor focal plane. Units are typically in mm and align with the rows and columns of an output image.