Orthophotography for the Gisborne District Council taken during 2012. Coverage encompassed the urban areas within the Gisborne District Council area.
Imagery was captured for ‘Boplass ltd and Gisborne District Council’ by NZ Aerial Mapping Ltd, 208 Warren Street, PO Box 6, Hastings 4156, New Zealand.
The supplied imagery is in terms of New Zealand Transverse Mercator (NZTM) map projection. The products are tiled into NZTopo50 1:1,000 tiles. Please refer to the supplied tile layout shape file for specific details, naming conventions, etc.
Imagery supplied as 12.5cm pixel resolution (0.125m GSD), 3-band (RGB) uncompressed GeoTIFF. The final spatial accuracy is +/-0.3m (@ 90% confidence).
Index tiles for this dataset are available as layer [Gisborne 0.125m Urban Aerial Photos Index Tiles (2012)](http://data.linz.govt.nz/layer/1750).
Data Acquisition: The Aerial Photography over this area was acquired using the UCXp and UXC camera systems on the following dates: 05 Jan 2012 06 Jan 2012 21 Jan 2012 15 March 2012
The data was collected flying 1900 - 2100 metres above lowest ground. These settings were selected to create a dataset with 0.125m GSD. NZAM used a number of LINZ geodetic marks, Geosystems iBASE and NZAM geodetic marks for the collection of GPS basestation data during the aerial data acquisition. Detail of these will be provided in the final project report. Independent of the aerial survey work Opus International Consultants Limited surveyed a series of ground control points for use in the Aerial Triangulation of the raw images, and for QA of the final orthophotos.
Data Processing: The sensor positioning and orientation (POS) was determined using the acquired GPS/IMU datasets and Applanix POSPac software. This work was all undertaken in NZGD2000 geodetic reference system using the data collected at the LINZ geodetic reference marks for the differential processing. The POS data was combined with the ground control in Aerial Triangulation (AT) to geo-reference the raw photography in NZTM map projection. This process was undertaken using Microsoft’s UltraMap AT and Leica’s ORIMA software. AT data, raw images and processed LiDAR DTM data were supplied to the orthophoto production team for Orthophoto Generation. All subsequent data processing steps were undertaken using Inpho’s OrthoVista, PCI and Socet Set processing software. The final orthophotos were checked for completeness of project coverage, general appearance and accuracy. The positional accuracy of the data has been checked by overlaying the Opus field surveyed features on the dataset. The data was found to fit well in position. The project specified positional accuracy of +/-0.3m (90% confidence) has been met.