Terralink

Page URL:	http://www.terralink.co.nz/newsroom/press_releases_archive/archive/9_august_2002.htm
Date Printed:	Friday, 10 September, 2010

Terralink International photogrammetric mapping for Waikato Regional Aerial Photography Syndicate - WRAPS 9 August 2002 Last year Terralink International won the contract to complete one of the most ambitious aerial photography, mapping and flying programmes that NZ has seen. The project is being completed for a consortium of councils and other agencies in the Waikato region. The syndicate involves the Department of Conservation, Waikato University, Environment Waikato and 9 district councils in the region. Terralink International will complete the photogrammetric mapping and are using New Zealand Aerial Mapping (NZAM), who is part owner of the company, to supply the planes for this project. This includes the only jet prop survey aircraft in the country, a 690Brockwell Commander. The project commenced in June 2001, however due to the particularly inclement weather during the September to April flying season, and the need for cloudless photography, not all of the flying was completed. The rest of the flying will be carried over into the coming flying season. The area being covered is some 25000 sq kms and in broad terms runs from just south of Auckland to south of Lake Taupo and from Rotorua across to the West coast. The purpose is to establish a photographic and ortho mapping resource and a snapshot of the region which will enable the consortium members to look at the region in a new light when it comes to resource management, district planning and effective contract administration. For more sophisticated planning the resulting imagery will allow planning for analysis of flood plains, design of new roads, land use analysis, forestry management, water use and general conservation management. The scale of the job has been significant says Dawn-Lee Hartley, business development manager of Terralink International. Over 3000 ortho photo tiles are being produced and the processing by Terralink International photogrammetrists is ongoing. A digital terrain model is first produced which is then used to create the ortho photos. The ortho photos will be at a scale of 1:5000 with a planar accuracy of +/- 3m accuracy and a ground sample distance (gsd ) of 1m. This means each pixel on the orthophoto relates to 1m on the ground. Careful planning of flight paths and photography lines was carried out to maximise flying time during the aerial photography flying season which goes from September to April. Outside these times the sunlight angle is not suitable for aerial photography.