Peatland Survey
We where commissioned by the Cairngorm National Park Authority to survey, map and model a very remote part of their estate above the town of Ballater, circa 300Ha last month for an upcoming Peatland Restoration project. The requirement: high resolution Orthomosaic, DTM, point clouds and a full 3d model. As you can see below the terrain was challenging, no access roads and over 220m in elevation change through the site.
We utilised the highly capable DJI Mavic 3 Enterprise with RTK to capture the data with the Emlid Reach RS2+ capturing the GCP data. Overall we captured 7000 images and 10 GCPs. Data processing was completed using Agisoft Metashape with some of the outputs generated through Virtual Surveyor and QGIS. We achieved 2.15cm/px resolution with an RMSE accuracy of 2.5cm in the X and Y and 3.2cm in the Z axis, Overall accuracy throughout the project was 4.76cm
Above are the Orthomosaic and Digital Terrain Model with a pdf overview with contours. File sizes at full resolution start to become huge 37Gb and 7Gb respectively, but do not worry we delivered numerous versions at differing resolutions for ease of viewing and analysis. Contours where generated at 1,2,5 and 10m intervals, Orthos and DTMs where delivered at Full, 5,10 and 20cm resolutions. The point cloud had 2,180,049,920 points taking nearly 10 hours to process. The 3d model had 23,442,944 faces, over 11m vertices taking just over 23 hours to process.
Why so much detail and resolution you may ask? Well having a solid baseline before work commences enables you to analyse and plan much more accurately without having to have boots on the ground, trampling through the peatland and heather damaging the environment you are trying to protect. Subsequent surveys can be re flown and data captured at lower resolution to monitor the project and then a final high resolution survey undertaken years later so that you can compare to the original.
Above are actual screen shots not photos of the 3d model we produced. Producing a 3d model on this scale and resolution This allows the client to accurately view and plan the restoration works needed.
