standards to provide accurate and high quality spatial data. SSE Renewables can be triangulated to give highly detailed elevation grids. To accurately geo-reference the data, ground truth surveys were also carried out by an experienced survey team from a number of control sites within the survey area, using Leica GPS stations.
Post-processing of the data is key to delivering an accurate product and Geomatics Group has been refining bespoke filtering and classification techniques for producing “bare-earth” Digital Terrain Models (DTM) for the past decade. This wealth of experience and a commitment to using the highest scientific standards has meant that Geomatics Group consistently deliver data of the highest quality, with a height accuracy typically in the region of +/-7cm.
The data delivered to SSE Renewables included: • LIDAR point cloud data with an average density of 4 points per square metre in ASCII xyz and LAS format
• LIDAR DTM and DSM at 1m grid in ASCII Grid format, plus xyz format for importing to AutoCAD
• Contour maps at 50cm intervals in AutoCAD format (.DWG or .DXF)
• Metadata as standard • Ortho-rectified aerial photography - georeferenced 24 bit TIFF images suitable for direct use in AutoCAD (.DXF or .DWG) at 25cm true pixel resolution
The Solution The data delivered has been used by SSE Renewables in a variety of ways to help in site selection, pre-planning and design. The contour maps were analysed in a CAD environment, providing detailed information on the effect of geological features, as well as surface features such as trees and buildings on wind speed. Wind drag and its potential to reduce energy yields were identified, enabling SSE Renewables to site and orientate the turbines, to support maximum electricity generation. High resolution DEMs derived from the LIDAR data were integrated with digital aerial photographs to improve access planning and to aid the planning application. Using GIS techniques, the integrated data was used to generate authentic 3D visualisations of the proposed site, which were particularly useful in the public consultation process. Archaeological consultants also used the aerial shots and the bare earth rasters to scan for archaeological finds such as hidden cairns or ring forts, especially under forestry.
Vegetation within the survey area were automatically isolated within the datasets, providing valuable information on tree height for line of sight applications and to determine the volume of tree stocks that would be affected by the development. Also, the development
of accurate topographic mapping was critical to civil and electrical design along the ridgelines and transmission line corridor.
The acquisition of new aerial LIDAR and other remotely sensed data can reduce the overall project survey costs and provide civil designers with accurate data in a short timeframe, for a multitude of wind farm design applications. The benefits to a project developer can include considerable time savings in survey acquisition and lower overall mapping, survey and engineering costs.
This technique is most effective for large sites and those covered in forest. Uses of LIDAR data in wind farm site selection and planning include:
• Site identification • Wind modelling and assessment • Transmission line routing • Road design • Cut and fill calculations • Line of sight analysis • 3D visualisation • Slope and aspect calculations • Risk management • Landscape Character Assessment • Visual Impact Assessment • Assessment of water environment impacts • Hydrological, Hydrogeological & Geological Assessments
• Detailed peat assessment and stabilisation studies • Drainage, run-off and sediment management
ENVIRONMENT INDUSTRY MAGAZINE |137|
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152