Aerial photography was captured over the Invercargill urban area in the Southland and Invercargill City Districts totalling approximately 585 km2. The area is located in the Southland Region of the South Island.
Data Acquisition The aerial photography for this project was captured within the 2021/22 flying season (September 2021 – April 2022).
The aerial imagery was captured on the following dates: 21 February 2022.
Camera and Flyng Height
All photography was captured using Vexcel's digital UCE camera fitted with the 100 mm lens and flown at an altitude of approximately 6,309 ft (1,923 m) with the lowest ground GSD set at 0.10 m.
Imagery captured with a minimum sun angle of +35 degrees. The sun angle of the imagery used for the orthorectification ranged from 36.1 to 53.7 degrees.
The flight survey number for this project is SN14232 The flight plan is named ‘Invercargill 10 cm UCE V2’ and comprises 30 runs, 1,328 frames. All imagery captured in stereo: forward overlap 60%, min 54%; side overlap 35%, min 15%. An additional 4 runs and 36 frames have been captured over tall structures with forward overlap and side overlap of 80%.
Imagery captured with no cloud or cloud shadow within the area of interest. Coastal and harbour imagery captured within 1.5 hours either side of low tide wherever possible.
Urban Building Displacement Specification Urban 0.10 m GSD imagery – using the UCE camera and by flying with 60% forward overlap and with 35% sidelap (standard stereo coverage) will achieve ~1 m building lean per 3 m height in the corners of the imagery used. Areas flown with 80% forward overlap and 80% sidelap will achieve ~0.37 m building lean per 3 m height in the corners of the imagery used. Tall structures inwards of the corner of the frame will have less lean the closer to the nadir they are. Increased (80/80) overlap flight runs captured over four sites in the urban area: • Southland meat processing plant, Crowe Rd, Underwood • Mill site located along East Rd, Kennington • Fertiliser works in Awarua • Aluminium smelter on Tiwai Peninsula Please note that building lean displacement in the CBD area has been managed with the 5 cm GSD urban capture.
A combination of existing control and LINZ benchmarks were used for aerial triangulation for this project.