The idea was first implemented by artists Hugh Pryor and Jeremy Wood, who have drawn a 13-mile wide fish in Oxfordshire and spiders whose legs reach across cities. They have also provided an answer to the question "What is the world's biggest "IF"?" It happens to be a pair of letters, "I", which goes from Iffley in Oxford to Southampton and back, and "F" which traverses through the Ifield Road in London down to Iford in East Sussex, through Iford and back up through Ifold in West Sussex. The total length is 537 km, and the height of the drawing in typographic units is 319,334,400 points. Typical computer fonts at standard resolutions are between 8 and 12 points.
"Wood and Pryor tend toward cartoonish shapes that look as if they're drawn by an Etch-a-Sketch. But they lately have also managed a few artfully nervous abstractions, made by strapping a G.P.S. device to a poodle, a border collie and a Jack Russell terrier, which betray a certain perhaps unwitting animal attraction to the work of Giacometti." 
In early 2014 programmer Joe Rosen released a GPS-A-Sketch GPS sketching app for iOS, available for free at the iTunes App Store