Ground Support: GPS base station support was sourced from continuously operating reference stations in and around the project area. Ground control points were existing field survey by Opus International Consultants. Surveys were conducted between 19 November 2015 and 13 May 2016.
Image Processing Workflow: - Flight planning - Aerial image acquisition - Imagery download and inspection - Combine and index imagery with post-processed GPS - Aerial triangulation and adjustment to ground control - Preparation of Client DTM - Vector Mapping if required – (not required for this project) - Editing or validation of DTM - Orthophoto creation - Image tiling - Colour profiling - Quality assurance
Block adjustment and orthorectification of the imagery was carried out using Visionmap and OrthoVista software.
Project specifications and technical processes were designed to achieve data accuracies as follows: - Orthophotos: +/- 0.15m (Basis of estimation: Project design) - Control: +/- 0.05m (Basis of estimation: Survey methodology used)
Metadata: - Photography: AAM, Visionmap A3-35 Edge, PRJ36531 - GPS Base Data: CORS, CORS, PRJ36531 - Field Survey Data: Opus, RTK GPS, 25250A - Horizontal Datum: NZGD2000/NZTM - Vertical Datum: NZVD2009, Auckland 1946 - Tidal Constraints: Within 2 hours of low tide - Minimum Sun Angle: 40 degrees