Frank Jacobs of big think has this piece on virtual geoglyphs, which combines mapping, art and... cycling. Michael Wallace is the Baltimore artist that uses his bike as the drawing tool and a map as his canvas, producing elaborate artwork visible only via Google Maps.

As Wallace traces shapes and forms across Baltimore's street grid, the GPS technology that tracks this movements fixes the fluid pattern of his pedalstrokes onto a map. The results are what Wallace calls GPX images, or 'virtual geoglyphs'.