Satellites are being used in a project to conserve the Sussex countryside.

The Sussex Downs Conservation Board Rangers are using a Global Satellite Positioning unit (GPS) across Sussex to create a digital record of the area.

Senior ranger Simon Culpin said: "We are using the GPS unit to produce a survey of the condition of the Downs to help protect the environment.

"The data will also be used in a wider project to create a 3D model of the Downs. The detailed virtual landscape could be used for scenario planning so we can look at the impact of large scale developments.

"If someone wants to put up a telecomms mast, we could play out the options to see what would happen."

The mobile unit has access to the US defence department's NAVSTAR satellite system that relays geographical information to GPS users around the world.

Mr Culpin said: "At the press of a button, a grid reference from the satellites is downloaded into the unit. The information is extremely accurate - down to one metre.

"Previous devices offered accuracy to ten metres but this is not good enough for our needs."

The GPS unit is linked to a database on a portable computer. The rangers select an object to be included in their studies, such as a gate, stile or vegetation, and call a grid reference from the satellites, which is automatically downloaded to the computer.

Observations about the location are recorded alongside the grid references to build a picture of the Downs.

All the information is transferred to a central computer where it is used to compile maps and work contracts.

Mr Culpin said: "We will use the information to create an in-depth study of the Rights of Way on the Downs.

"We have more than 2,000 miles of public pathways that need to be monitored and maintained. This autumn, we will start walking the pathways with the GPS unit to record every detail of the network."

The project was due to start earlier this year but floods and movement restrictions because of the foot-and-mouth crisis had made access to the Downs difficult.

Mr Culpin said: "Now that all restrictions have been lifted, we can get going with this project.

"We only have one GPS unit and more than 140 parishes to cover - it takes a year to map just 30.

"The job will be a bit like painting the Forth Bridge. By the time we have finished a circuit, it will be time to go back to the start and update the information.

"It will take about five years to compile the first set of data and after that, the process should speed up as rangers will be noting changes rather than starting from scratch."

The results of the Rights of Way network study will be made available on South Downs virtual information centre web site when the first areas have been mapped by 2003.

The site has information and advice for visitors to the Downs, including a report area for problems found in the countryside and suggested walks.

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