Safari by satellite

The biggest elephant in Brighton - and the world

Satellite tracking is commonly used to avoid traffic jams. But it is now being used to find elephants in Brighton, writes BBC News Online's technology correspondent Mark Ward

The evidence of our effect on the land is all around us.

Roads divide landscapes, hills are shorn of their trees, tunnels are punched through mountains and cities pockmark the countryside with pavements and homes.

Being largely functional, any grim beauty these artefacts possess is likely to be accidental.

But just occasionally, humankind chooses to make its mark in a more fitting way, one that works with the world instead of trampling it underfoot.

We found various creature like squiggles but nothing very 'Rembrandt'

Jeremy Wood

Figures carved in chalk, like the White Horse of Uffington, Berkshire, UK, and the Cerne Abbas giant, and even the vast figures traced in the deserts of Peru, announce our presence with all the certainty of a block of flats. No-one needs to be told which are easier on the eye, though.

Now, Jeremy Wood and Hugh Pryor have brought the methods for drawing these figures into the 21st Century. Using this technique they have found a vast elephant in Brighton, a giant fish in Wallingford and an enormous butterfly in Nottingham.

But unless you know where to look you will never see them.

Instead of carving their figures in a hillside or in the dust of the South American desert, the pair have instead used a GPS handset to mark out the shapes created by roads.

Path records

The Global Positioning System is the constellation of 24 satellites orbiting the Earth that are constantly beaming down timing signals that a GPS handset uses to work out just where it is.

Carved in chalk: The Cerne Abbas giant

Almost every GPS handset can be set to record the path you take as you travel - a feature that can be very useful if you need to retrace your steps, or if you need to find a swifter way to reach your destination.

It has also proved useful for Mr Wood and Mr Pryor in the creation of their works of GPS art.

It all started on a rainy afternoon in late summer when the pair were looking for something to do to stave off boredom.

Being artistic types, they photocopied some road maps and started looking for recognisable shapes created by layout of roads and streets.

"We found various creature like squiggles," Mr Wood told BBC News Online, "but nothing very 'Rembrandt' - more borderline Play School."

Big fish

Then they spotted a fish created by the roads around Wallingford in Oxfordshire. Enthused by the discovery, they jumped in the car and spent the next three hours carefully tracing its outline, using the GPS handset to record their path.

As the technologist of the duo, Mr Pryor then hacked together a program that let them view their data in 3-D.

Using this they confirmed that it is indeed a very big fish. If you were to walk its outline you would travel about 108.5 kilometres (67.4 miles).

Since then they have been finding and tracing more figures on the landscape.

Chaos theory

One recent creation was the Nottingham butterfly. This was again done in a car, and demanded the crossing of the M1 six times in the space of the four hours it took to trace it out.

The dingy used to create images on water

Mr Wood even found an elephant lurking in the streets of Brighton and Hove. A journey of 11.2 kilometres (6.9 miles) made it possible for everyone to view it.

Mr Wood has even let a dog called Boris trace his own figures, though these tended to follow a logic which is all the dog's own.

Mr Wood and Mr Pryor are not the first to convert GPS tracking data into works of art. In 1997, Italian artist Andrea Di Castro started using just such a technique to trace the outlines of large geographical features such as lakes.

He even created a few figures, but none as large as the creations of Mr Wood and Mr Pryor. The trail they have blazed is one that everyone can follow.