Cheating...

[masque]

If you look at the work of an artist such as Vermeer. He used a form of 'camera' to project an image onto the canvas which he then traced. In fact many artists have used similar techniques to lay down the basic structure or composition of interiors or still life images. It was possible to do the same with landscape projecting an image into a darkened tent.
A slightly less 'cheaty' method was to draw on a gridded paper or canvas while looking through an identically proportioned grid which simplifies getting the proportions in a drawing right a great deal.
Tracing a photograph using tracing paper or a pantograph or now on a computer using vector or pixel software is just a development of the same idea.
Nothing to do with cheating really while at the same time being a very definate cheat.
Derek