Aerial Photogrammetric survey

A rapid and cost-effective way to produce 3D models, high resolution imagery and digital terrain models

DATA COlLECTION

Photogrammetric modelling relies on using numerous overlapping aerial photographs to triangulate the 3D geometry of features, whether they be terrains or individual structures and buildings.

 

Historically, manned aircraft would be used to acquire the data at significant cost; however, the rise of drones in recent years has allowed aerial imagery to be collected  significantly more economically.

Geo-4D's fleet of fixed-wing and multirotor drones means we will always have the right aircraft for the job, whether it be a long endurance fixed-wing aircraft for expansive terrains, or a smaller and more agile multicopter for modelling a complex structure.

Aerial data acquisition is completed using pre-planned flights where the drone is programmed to collect images at specific waypoints. Ground control points are surveyed using an RTK GPS system to ensure the processed data are accurately georeferenced.

Data collection is rapid, with a square kilometre being fully mapped in less than 1 hr at a resolution of 2 cm.

Our team of in-house CAA-approved pilots mean you be certain the job will be performed professionally and safely.

data Processing and delivery

Photogrammetric processing is performed in-house using a variety of software.

During data processing, the imagery and ground control points are used to triangulate an accurate and dense point cloud across the site. The point cloud is cleaned and used to derive various high resolution output files:

  • Raw full density colourised point cloud

  • Classified point cloud (trees, buildings, roads etc.)

  • Orthomosaic aerial image

  • Digital surface model (includes trees, structures etc)

  • Digital terrain model

  • 3D textured mesh

  • Thermal (radiometric) map

  • Reflectance maps (R, G, B, near-IR, rededge)

  • Normalised difference vegetation index

 

From the processed data, additional interpretation and assessments can be performed to provide:

  • CAD drawings

  • Volumetric calculations

  • Topographic plans

  • Fault mapping

All datasets can be delivered individually, or hosted on our secure online GIS portal, where multiple users can view and interrogate a variety of datatypes.

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