Three-year project on mapping

Press, 26 October 1982, Page 33

Three-year project on mapping

An era in the science of remote sensing has been reached in New Zealand on the completion of a threeyear Earth Resources Management Project, jointly sponsored by the Government and 1.8. M. This is according to the Minister of Science and Technology. Dr lan Shearer, who handed over the report to the managing director of 1.8. M. New Zealand. Ltd. Mr Basil Logan, in Wellington recently. The report demonstrated

the use of computerised data from satellite and aircraft multispectral scanning cameras for flat land agricultural and oceanographic mapping, assessing land use in hilly unaccessible terrain, and monitoring exotic and indigenous forests in the King Country and Canterbury. Using 1.8. M. computer software and 1.8.M.'s Sydneybased facilities, the project established a New Zealand multi-disciplinary remote sensing group with members from the Government, departments of Scientific and Industrial Researach, Lands and Survey. Agriculture and Fisheries, and the Forest Service. The remote sensing section at the D.S.I.R.'s physics and engineering laboratory in Lower Hutt, which was first established in 1974, was the co-ordinating group. The project was conducted in two phases. Information from the Landsat Two satellite, launched by the United States National Aeronautics and Space Administration in 1975, gave a large regional view from a height of 920 km, of the King Country and Canterbury. An 11 channel multispectral scanner gave a more localised perspective as an aeroplane flew over the same areas. All information was recorded as numbers on magnetic tapes. These were converted by computer into a colourful display on a visual display unit or a hard copy photograph, each colour having a different meaning for the "informed" user. For example, the Landsat photographic maps showed green healthy pasture in red.

forests in brown, and water sediment as varying shades of blue. However, this is an oversimplification. according to a D.S.I.R. botanist.. Ms Susan Timmins, who said the numbers were processed and analysed according to their reflectance values. She said the satellite information was recorded in four wavelengths, two in the visible and two in the infrared. Aircraft scanner information was recorded in 11 wavelengths. "As only three wavelengths can be displayed at any one time, the ones we use depend on .what we want to analyse," she said. Ms Timmins believes remote sensing is a valuable addition to a map maker's tool kit. It is a seventh of the cost of conventional ground surveys. “We manipulated data from the aircraft scanner to simulate that of future satellites and produced a Darfield map showing barley, wheat, potatoes, peas, dry and green pasture, and bare ground," she said. "If New Zealand had an earth resources satellite receiving station we could have this sort of information ‘on line’ and thus be able to supply farmers, foresters, land managers, environmentalists and fisheries people with up-to-date information." The question of a receiving station had been put to a Government interdepartmental committee which would report to the Minister of Science and Technology soon, and communications aspects had been referred to the Communications Advisory Council. Ms Timmins said.