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Member:sungbeanJo_GG [2020/11/24 20:20] sungbean |
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| - | There were two sources of ground elevation data used | + | The trial has successfully demonstrated ROSEN’s |
| - | within this trial, the Environment Agency (EA) LiDAR and | + | methodology to estimate the depth of cover over |
| - | Ordnance Survey Terrain 5 data. | + | pipelines. This includes producing an accurate |
| - | The EA [6] offer LiDAR data with a spatial resolution of | + | pipeline centreline from data obtained during a |
| - | between 25 cm and 2 m. It is currently stated by the EA | + | routine internal inspection, combined with ground |
| - | that accurate elevation data is available for over 75% of | + | elevation data available from the Environment |
| - | England. The absolute height error is quoted to be less | + | Agency (EA) to calculate depth of cover. |
| - | than ±15 cm. This is the root mean square (RMS) error. | + | • The results of the calculation have been validated |
| - | The Ordnance Survey (OS) Terrain 5 data [7] has a quoted height error of ±1.5 m. This is the RMS error for urban | + | against infield depth of cover measurements obtained using a pipe and cable locator. The accuracy |
| - | and major communication routes. For rural and mountain | + | of the depth of cover results has been calculated |
| - | and moorland areas the error is higher at ±2.5 m. The | + | using a root mean square (RMS) error method. This |
| - | spatial resolution for all OS Terrain 5 data is 5 m. | + | has determined an overall accuracy of ±0.15 m using EA LiDAR data. |
| - | Figure 2: Example Depth of Cover Report | + | • Infield ground surface measurements were compared with the EA LiDAR and OS Terrain data. A |
| - | (Aerial imagery source: Esri, DigitalGlobe, GeoEye, Earthstar Geographisc, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN and the GIS User Community) | + | |
| - | Figure 1: Example of points provided from post inspection data processing | + | |
| - | RESEARCH / DEVELOPMENT / TECHNOLOGY | + | |
| - | Given the better spatial resolution and greater accuracy | + | |
| - | of the EA LiDAR data, this was the preferred dataset for | + | |
| - | use in this trial. However, examination of the available | + | |
| - | EA LiDAR data identified that there was not full data | + | |
| - | coverage of the trial pipeline. A 6 km missing section | + | |
| - | of EA LiDAR data was supplemented with OS Terrain 5 | + | |
| - | data for the trial. | + | |
