Data Acquisition

The aerial photography for this project was captured within the 2019/20 flying season (September 2019 – April 2020).

Camera and Flying Height

All photography was captured using Vexcel's digital UCE camera fitted with the 100 mm lens. Urban areas flown at an altitude of approximately 4,732 ft (1,441 m) with the lowest ground GSD set at 0.075 m.

Capture Dates

The aerial imagery was captured on the following dates:

18 January 2020

Sun Angle

Imagery captured with a minimum sun angle of +45 degrees. The sun angle of the imagery used for the Timaru orthorectification ranged from 48.8 to 66.4 degrees.

Flight Planning

The flight survey numbers for this project are: SN14089 Timaru Urban 7-5cm UCE V2 comprising 36 runs, 639 frames

All urban imagery captured in stereo: forward overlap 60%, min 54%; side overlap 35%, min 15%.

Timaru CBD area imagery captured in stereo: forward overlap 80%; side overlap 80% to help reduce building lean.

Environmental Specification

Imagery captured with no cloud or cloud shadow within the area of interest. Imagery for all harbour, coastal and tidal areas acquired during low tide periods, being two hours either side of low tide.

Rivers captured at time of low river flow.

Urban Building Displacement Specification

Urban 0.075 m GSD imagery – using the UCE camera and by flying with 60% forward overlap and with 35% sidelap (standard stereo coverage), maximum 1.1 m building lean per 3 m height within the image model area. Imagery over the Timaru CBD areas captured with 80% forward overlap and 80% sidelap to achieve maximum 0.37 m building lean per 3 m height within the image modeal area and produce a near true ortho product.

Ground Control

A combination of existing control and LINZ benchmarks were used for aerial triangulation for this project.