Bearna, Galway
Volumetric Analysis
PROJECT OVERVIEW
AltiGeo was appointed to carry out a drone survey and volumetric analysis for a large residential development site in Bearna, located west of Galway City. The proposed scheme forms an extension to the existing Cnoc Fraoigh / Heather Hill housing development and comprises 197 residential units, including apartments, duplexes, terraced houses, semi-detached houses, and detached houses.
Survey Requirement
The client required an accurate photographic record and online viewable model of the site to assess the existing ground conditions and volumetric analysis of soil heaps to calculate potential cut and fill for the site. The under-construction site covered a large development area with varying levels, earthworks, access routes, and surrounding context, making drone photogrammetry an efficient method of data capture.
Drone Survey Method
The drone survey was carried out between 10:30am and 12:30pm. A total of 2,303 images were captured with metadata, using an 80% image overlap to ensure sufficient coverage and accuracy across the site.
The flight altitude was 75m, covering an area of approximately 28.2 hectares. RTK positioning along with Ground Control points and check points were recorded with a GeoMax Zenith 35 GNSS to ensure cm level accuracy.
Photogrammetric Model
The captured drone imagery was processed into a geolocated photogrammetric model of the site. This provided an accurate 3D digital record of the existing site condition, allowing the model to be explored easily online.
The photogrammetric model was then used as the basis for volumetric analysis, allowing cut-and-fill quantities and earthwork conditions to be reviewed from the captured survey data.
Scan Details
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Date of scan: 18 April 2024
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Time and duration: 10:30am – 12:30pm
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Weather: Cloudy and windy
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Flight altitude: 75m
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Images captured: 2,303
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Image overlap: 80%
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Area scanned: 28.2 hectares
Deliverables
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Geolocated photogrammetric model
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Photographic record of existing site condition
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Drone survey dataset
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Volumetric analysis outputs
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Online Viewable 3D model for site review and coordination