Geospatial Survey of Dam

PROJECT OVERVIEW

Consulting engineers required spatial and visual data of a dam, the buildings and surrounding areas to complete geotechnical assessment, inspection, planning and design of upgrade works. This included a high resolution terrain model of the entire site, photorealistic 3D model for visualisation, and high definition survey of pumping station.

Due to the large area, hard to access nature of the dam and multiple stakeholder involvement, conventional survey would be inefficient and costly.

Project Scope

DIOSPATIAL SOLUTION

Diospatial developed a complete reality capture spatial solution that utilised the most ideal capture techniques to best achieve the spatial and visualisation needs of the project.

First, a robust network of ground control points were established throughout the site to ensure all spatial data was geo-located and spatially accurate.

The capture technique that would best achieve the spatial data requirements was chosen—including drone LiDAR, drone photogrammetry, and terrestrial laser scanning.

Drone LiDAR was used to create the digital terrain model. The LiDAR was captured at a very high point density to allow for high resolution and accurate terrain modelling, even in areas of vegetation cover. From the LiDAR point cloud, ground and non-ground returns were classified and from this a surface mesh model was produced to show the bare earth terrain beneath vegetation. Elevation contours and rudimentary watershed analysis was extracted from the LiDAR point cloud.

Drone-based imagery was captured and used to create a spatially accurate and rich 3D visualisation of the site. Specific attention was given to the down stream left abutment where imagery was captured underneath the tree canopy. In post-processing, Diospatial data technicians “removed” the tree canopy from the 3D model to allow for inspection and clear visualisation of the terrain beneath.

High definition terrestrial laser scanning was completed of the pumping station to produce a high definition, high accuracy point cloud to support detail design of upgrades.

All spatial deliverables were compiled in to a web-based 3D digital twin and hosted via an online portal, Pointerra. This allowed project stakeholders to easily view and interrogate the data, take measurements and collaborate, without the need for specialist software or powerful computing hardware.