Mapping firm Terralink International has begun the largest segment of a plan to get high-resolution digital imagery of the entire country of New Zealand. Two planes are to fly 42,000 kilometres from Kaikoura to McKenzie Basin, taking 2500 photos to produce 5500 “orthophoto tiles” at a resolution of 75 centimetres.
The orthophoto images remove distortions caused by the angle of flight, elevation and camera edges. This is done by running digitised photos through special software and aligning features with known physical landmarks. Terralink has arranged a deal with a consortium of local authorities and the Conservation Department which will share the data and the costs of the mapping exercise. Terralink chief executive Mike Donald says though there are existing images of sufficient resolution for main urban areas, the same is not true for rural land. Satellites would provide another way of getting the same data, but Mr Donald says the cost of satellite imagery is prohibitive and there are issues with clouds getting in the way.
Last year, a similar high-resolution mapping project was completed in Waikato. Other areas to be covered this year include Nelson, Marlborough and Northland. Mr Donald says these types of maps are what the market is demanding because of global positioning system (GPS) technology.
Farms are starting to use GPS technology to record boundaries, troughs and fences. Fertiliser firms use GPS for spreading. When a flood hits an area, the latest satellite imagery can be compared to the maps to see the extent of the damage. The ortho-images are also sufficiently accurate for building permit and resource consent use as well as other land-management purposes. Terralink was a state-owned enterprise till it was put into receivership and then bought out by private investors in 2001.
It is now owned by Dunedin’s Animation Research, Australian firm Earth Science Corporation, and Mike and Lesley Bundock. Mr Donald says Terralink is trading profitably, having spurned very large high-risk international projects and instead focused on smaller international projects using specialised technology. It has 100 staff with offices in Albany and Wellington.