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Transforming Land Surveys: Ely Aerial Imaging Achieves Sub-20mm Accuracy for Major Development in the North of the UK

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Project Overview

A major new residential development in the North of England required a detailed topographical survey to assist with site planning, earthworks, and drainage design. Ely Aerial Imaging was commissioned to deliver a high-accuracy survey of the 50-hectare site. The client’s requirement was for sub-20mm accuracy in multiple output formats, including digital elevation models (DEM), orthomosaics, and 3D point clouds.

Objectives


  1. Provide a high-resolution topographical map of the site with sub-20mm accuracy.

  2. Deliver data in multiple formats: orthomosaics, contour maps, DEM, and 3D models.

  3. Complete the survey within a short timeframe to meet the client’s project milestones.


Methodology

1. Pre-Flight Planning


  • Site Assessment: A preliminary site visit identified potential obstacles, airspace permissions, and suitable locations for ground control points (GCPs).

  • Flight Path Design: Using specialized mission planning software, Ely Aerial Imaging designed an overlapping grid flight pattern to ensure comprehensive coverage and redundancy.

  • Weather Considerations: The survey was scheduled on a day with clear skies and minimal wind to ensure optimal data capture.


2. Equipment


  • Drone Used: DJI Matrice 300 RTK equipped with a Zenmuse P1 photogrammetry camera.

  • Ground Control Points (GCPs): 20 evenly distributed, high-visibility GCPs and 10 checkpoints were placed across the site and surveyed using an RTK-enabled GNSS receiver for precise georeferencing.


3. Data Collection


  • Drone Flights: The drone flew at an altitude of 70 meters, capturing high-resolution imagery with 80% front and side overlap. A total of 2,000 images were captured in a single day of flying.

  • Ground Control Points: Each GCP's coordinates were recorded to centimetre-level accuracy using the GNSS receiver. GCPs ensured that drone imagery could be georeferenced to the real-world coordinate system.


4. Data Processing


  • Photogrammetry Software: Reality Capture was used to process the imagery and generate a georeferenced 3D model.

  • GCP Integration: The GCP data was incorporated into the processing workflow to enhance model accuracy.

  • Outputs Generated: Orthomosaic: High-resolution georeferenced imagery of the site. Digital Elevation Model (DEM): Surface-level data used for elevation profiling. 3D Point Cloud: Dense point cloud data for further CAD modelling. Contour Maps: Contours generated at 0.5m intervals.


5. Quality Control


  • The outputs were rigorously checked against known coordinates. Sub-20mm accuracy was verified.


Results


  • Accuracy Achieved: The final survey achieved a root mean square error (RMSE) of 16mm, exceeding the client’s sub-20mm accuracy requirement.

  • Delivery Time: The entire project, from planning to data delivery, was completed in just five days.

  • Deliverables: Ely Aerial Imaging provided the client with: A high-resolution orthomosaic. A DEM with accurate elevation data. A 3D model in both .OBJ and .LAS formats. Contour maps in .DXF format for CAD integration.


Challenges and Solutions


  1. Large Site Coverage:

  2. Accuracy Requirements:

  3. Data Volume:


Client Feedback

The client praised the professionalism and technical expertise of Ely Aerial Imaging. The sub-20mm accuracy and variety of deliverables enabled seamless integration into their design workflow, significantly accelerating project timelines.

Conclusion

This project highlights the capability of Ely Aerial Imaging to deliver precise, high-quality survey data using cutting-edge drone technology and advanced photogrammetry workflows. The successful completion of this project demonstrates that drone imaging is a viable and cost-effective alternative to traditional surveying methods for large-scale developments.

Ely Aerial Imaging is a leading provider of professional drone-based imaging and surveying solutions, specialising in high-accuracy data collection for construction, infrastructure, environmental, and development projects. Based in the UK, the company leverages cutting-edge UAV technology and advanced photogrammetry software to deliver precise aerial surveys, 3D mapping, orthomosaics, and thermal imaging. Known for their commitment to quality, innovation, and safety, Ely Aerial Imaging consistently meets the demands of complex projects, offering clients reliable, cost-effective, and timely results. Whether for topographical surveys, progress monitoring, or inspection work, Ely Aerial Imaging is at the forefront of transforming traditional workflows with drone technology.


To discuss your project call our office on 01353 880988 email info@elyaerialimaging.com or visit www.elyaerialimaging.com 


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