Whanganui 0.075m Urban Aerial Photos (2022)

Whanganui 0.075m Urban Aerial Photos (2022)

Toitū Te Whenua Land Information New Zealand

2022

Index Tiles ONLY, for actual orthophotos see layer [Whanganui 0.075m Urban Aerial Photos (2022)](http://data.linz.govt.nz/layer/113251)

Orthophotography within the Manawatū-Whanganui Region captured in the flying season of 2022-2023. Coverage encompasses Whanganui urban areas.

Imagery was captured for Whanganui District Council by Aerial Surveys Ltd, Unit A1, 8 Saturn Place, Albany 0632, New Zealand.

Data comprises:
• 896 ortho-rectified RGB GeoTIFF images in NZTM projection, tiled into the LINZ Standard 1:1000 tile layout.
• Tile layout in NZTM projection containing relevant information.

The supplied imagery is in terms of New Zealand Transverse Mercator (NZTM) map projection.

Imagery supplied as 7.5cm pixel resolution (0.075m GSD), 3-band (RGB) uncompressed GeoTIFF. The final spatial accuracy is ±0.15 at 95% confidence level in clear flat areas.

Project

Aerial photography was captured over the Whanganui urban area in the Whanganui District totalling approximately 263 km2.

The area of capture is located in the Manawatū-Whanganui Region of the North Island.



Data Acquisition
The aerial photography for this project was captured within the 2022/23 flying season (September 2022 – April 2023).

Camera and Flying Height
All photography was captured using Vexcel's digital UCE-3 camera fitted with the 100 mm lens and flown at an altitude of approximately 6,184 ft (1,885 m) with the lowest ground GSD set at 0.075 m.

Capture Dates
The aerial imagery was captured on the following dates:
27 December 2022.

Sun Angle
Imagery captured with a minimum sun angle of +40 degrees. The sun angle of the imagery used for the orthorectification ranged from 56.4 to 73.2 degrees.

Flight Planning
The flight survey number for this project is SN14261
The flight plan is named ‘Whanganui-2023-Urban-UCE3’ and comprises 19 runs, 672 frames. All
imagery captured in stereo: forward overlap 60%, min 54%; side overlap 35%, min 15%.

Environmental Specification
Imagery captured with no cloud or cloud shadow within the area of interest.

Urban Building Displacement Specification
Urban 0.075 m GSD imagery – using the UCE-3 camera and by flying with 60% forward overlap and with 35% sidelap (standard stereo coverage) will achieve ~1m building lean per 3m 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.

Mapping area: 175.55 km 2

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



Data Processing
All aspects of the data processing from imagery processing to DTM creation and ortho production
and product deliverables was undertaken in-house by Aerial Surveys staff.

Map Projection
All spatial data for this project provided in terms of New Zealand Transverse Mercator 2000 map
projection (NZTM2000). The ellipsoidal datum is New Zealand Geodetic Datum 2000 (NZGD2000).
The airborne GPS and ground control GPS data was converted from ellipsoidal heights into orthometric heights using the LINZ NZGeoid16 separation model. For this project the orthometric vertical datum is New Zealand Vertical Datum 2016 (NZVD2016).

Image Processing
Level-0 to Level-3 image processing carried out using UltraMap software. All imagery has gone
through QA checks ensuring there is no cloud cover and cloud shadow. During aerial acquisition the aircraft on-board GPS navigation data and ground base station data collected and post processed.
Level-3 imagery process provides model based colour correctness/radiometry and even tonal balance across each project area.

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