Terralink starts biggest aerial photography task

Terralink starts biggest ever aerial photography task

New Zealand’s largest and most ambitious aerial photography job starts this month in the South Island.

Two specially equipped planes will cover more than 42,000 square kilometres from Kaikoura to the McKenzie Basin for land information, mapping and data integration company Terralink International.

Approximately 2,500 photos will be taken and produced into 5,500 orthophoto tiles to create the most comprehensive, high resolution imagery available of this territory. The work follows a similar task completed last year for Waikato. Terralink is aiming to produce detailed photography across the entire country as part of its National Imagery Acquisition Project.

Terralink CEO, Mike Donald, says some urban areas already have similar imagery available but rural New Zealand is poorly covered.

The ortho-images produced from the aerial work are a map-accurate photograph and can be used by local authorities for building permit and resource consent work, soil studies and land use analysis, vegetation classification and pest management, data overlay of roads and boundaries and other asset management responsibilities.

The mapping would also be vitally useful during civil defence emergencies like February’s North Island flooding. If such detailed data was available it could be used to estimate which properties and infrastructure throughout a region would be affected by rising flood waters and overlayed across each area to pinpoint houses, sheds, fences and other property either underwater or washed away. Terralink has worked for about a year to put together a consortium of South Island local authorities and other agencies that will use the new data in a myriad of ways and also benefit from the cost savings achieved by sharing in the project, says Mr Donald.

The aerial photography work will be particularly challenging because of the South Island’s diverse altitude and terrain. Terralink’s Imagery Manager, Dave Froggatt, says the planes will fly a total of 30 runs, some up to about 600km long. The photos will be digitally scanned, knitted together and matched up with GPS (Global Positioning System) co-ordinates of known points on the ground.

If Terralink can achieve its aim of providing such data across all New Zealand it will result in seamless, integrated imagery, instead of the existing piecemeal, fragmented information.

“It significantly strengthens the land base data Terralink already has available and builds on its reputation as the prime source of land data in New Zealand,” says Mr Donald.

When Terralink has complete coverage it will be an important platform for GIS (Geographic Information System) use, linking in with satellite imagery, such as that from the Quick Bird satellite which flies over New Zealand every three days. Comparisons of data would give fast and easy analysis of the extent of any land use and environmental changes.

The information is likely to also be useful for farmers who are increasingly relying on GIS and computerised programming for farm management, including fertiliser application, and placement of fences and troughs.

Terralink says the aerial work is likely to continue into next year. The changing angle of the winter sun restricts aerial photography work to an August-to-April flying season. The work is likely to extend beyond the end of this season, although a stable, high pressure weather pattern might allow the work to be completed this year.

Councils involved include Waimakariri, Ashburton, Timaru, Waimate, Waitaki, McKenzie, Environment Canterbury, and Department of Conservation, although the coverage will also take in districts of the Kaikoura, Hurunui, Selwyn and Banks Peninsula councils.

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