The practice of laying a grid on top of a drawing, then painstakingly copying each line of the drawing to the corresponding cell of a blank grid seems old-fashioned in these days of pervasive photocopying and electronic image manipulation.
Nonetheless, the underlying idea of transferring information from one grid to another has a long history in both mathematics and art. When the blank grid differs from the original grid, for example, a drawing can suffer intriguing distortions. In art, the result is sometimes called an anamorphic picture. Mathematically, you’re looking at the results of a type of transformation or mapping.