UK-Wales Elevation Model: Difference between revisions
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[[Image:UkWales_MynyddClogau.png|right|thumb|400px|Wind farm at Mynydd Clogau, Wales. Transparent areas are where no LiDAR scans are made. If loading the data in an elevation grid object, these areas can easily be void-filled with other sources such as the 50m gridded data from OS Land Form or OS Terrain.]] | [[Image:UkWales_MynyddClogau.png|right|thumb|400px|Wind farm at Mynydd Clogau, Wales. Transparent areas are where no LiDAR scans are made. If loading the data in an elevation grid object, these areas can easily be void-filled with other sources such as the 50m gridded data from OS Land Form or OS Terrain.]] | ||
== Introduction == | == Introduction == | ||
The UK - Wales Elevation model in 5m grid resolution is a digital terrain model (DTM) produced from higher resolution LiDAR scans originally obtained from the Natural Resources Wales. The original model at 2m resolution is named ‘LiDAR Composite Dataset – DTM – version 2m.’ The derived elevation model delivered with windPRO is at 5m resolution – and is bi-linearly resampled by EMD to obtain a slightly coarser resolution - 5m – this is done in order for the data to be operational for the large areas needed in the context of wind farm analysis’. Coverage for the data is approximately 70% of | The UK - Wales Elevation model in 5m grid resolution is a digital terrain model (DTM) produced from higher resolution LiDAR scans originally obtained from the Natural Resources Wales. The original model at 2m resolution is named ‘LiDAR Composite Dataset – DTM – version 2m.’ The derived elevation model delivered with windPRO is at 5m resolution – and is bi-linearly resampled by EMD to obtain a slightly coarser resolution - 5m – this is done in order for the data to be operational for the large areas needed in the context of wind farm analysis’. Coverage for the data is approximately 70% of the country. | ||
== Accuracy == | == Accuracy == | ||
The following accuracy statement was | The following accuracy statement was provided by the Natural Resources of Wales for the LiDAR datasets (at higher resolution). For the 5m gridded data, expect a slightly lower acurracy. | ||
* Vertical (height): Specifications requiere RMSE of 0.15m or better. More recent surveys have shown the error to be 0.05m. | * Vertical (height): Specifications requiere RMSE of 0.15m or better. More recent surveys have shown the error to be 0.05m. | ||
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== Usage Notes == | == Usage Notes == | ||
# Download and processing time is in minutes - so please be patient! Due to the large amounts of high-resolution elevation data and the tile-based storage system, you will experience that downloading the data for a site may last a few minutes. Please consider downloading 'smaller' areas (say 10km x 10km instead of 20km x 20km) | # Download and processing time is in the order of minutes - so please be patient! Due to the large amounts of high-resolution elevation data and the tile-based storage system, you will experience that downloading the data for a site may last a few minutes. Please consider downloading 'smaller' areas (say 10km x 10km instead of 20km x 20km) | ||
# Since only 70% of the territory of Wales are covered by the LiDAR scans - you may need to void-fill some areas. If you download the data into an elevation grid object, these void-areas can easily be filled with other ready available sources such as the 50m gridded data from OS Land Form or OS Terrain. | # Since only 70% of the territory of Wales are covered by the LiDAR scans - you may need to void-fill some areas. If you download the data into an elevation grid object, these void-areas can easily be filled with other ready available sources such as the 50m gridded data from OS Land Form or OS Terrain. | ||
# Higher resolution data exist for selected areas in the region based on more recent LiDAR surveys: These are in resolutions from 0.25m to 2m – and may be accessed directly from the geodata-portal of Wales (see link below). More information about the Wales Lidar products can be found in the [[:File:LiDAR_Guidance_2018.pdf|LiDAR Guidance]] document from the Natural Resources Wales. | # Higher resolution data exist for selected areas in the region based on more recent LiDAR surveys: These are in resolutions from 0.25m to 2m – and may be accessed directly from the geodata-portal of Wales (see link below). More information about the Wales Lidar products can be found in the [[:File:LiDAR_Guidance_2018.pdf|LiDAR Guidance]] document from the Natural Resources Wales. | ||
Revision as of 14:12, 14 June 2019
Introduction
The UK - Wales Elevation model in 5m grid resolution is a digital terrain model (DTM) produced from higher resolution LiDAR scans originally obtained from the Natural Resources Wales. The original model at 2m resolution is named ‘LiDAR Composite Dataset – DTM – version 2m.’ The derived elevation model delivered with windPRO is at 5m resolution – and is bi-linearly resampled by EMD to obtain a slightly coarser resolution - 5m – this is done in order for the data to be operational for the large areas needed in the context of wind farm analysis’. Coverage for the data is approximately 70% of the country.
Accuracy
The following accuracy statement was provided by the Natural Resources of Wales for the LiDAR datasets (at higher resolution). For the 5m gridded data, expect a slightly lower acurracy.
- Vertical (height): Specifications requiere RMSE of 0.15m or better. More recent surveys have shown the error to be 0.05m.
- Horizontal (planar): Absolute spatial error is 0.40m
Usage Notes
- Download and processing time is in the order of minutes - so please be patient! Due to the large amounts of high-resolution elevation data and the tile-based storage system, you will experience that downloading the data for a site may last a few minutes. Please consider downloading 'smaller' areas (say 10km x 10km instead of 20km x 20km)
- Since only 70% of the territory of Wales are covered by the LiDAR scans - you may need to void-fill some areas. If you download the data into an elevation grid object, these void-areas can easily be filled with other ready available sources such as the 50m gridded data from OS Land Form or OS Terrain.
- Higher resolution data exist for selected areas in the region based on more recent LiDAR surveys: These are in resolutions from 0.25m to 2m – and may be accessed directly from the geodata-portal of Wales (see link below). More information about the Wales Lidar products can be found in the LiDAR Guidance document from the Natural Resources Wales.
Availability from within windPRO
The data are available directly from within windPRO in 5-meter grid resolution. The data can be accessed from the online-services in the following objects:
- Line Object (with purpose to height contour lines)
- Elevation Grid Object
Reference System
The following reference systems were used in the original data:
- Horizontal: OSGB36 British National Grid (EPSG: 27700)
- Vertical: Elevations recorded above Ordnance Datum Newlyn
License and Attribution
The product belongs to the open geospatial data of the Natural Resources Wales. The data are license under a under a ‘Open Government License for Public Sector Information’. This license is compatible with the Creative Commons Attribution License 4.0. Please use the following attribution when using this dataset:
- Source: Contains Natural Resources Wales Information ©. Natural Resources Wales and database right. Adapted and distributed by EMD and windPRO.
Acknowledgements
- The Welsh Government, Natural Resources Wales and the public of Wales are thanked for producing this digital elevation dataset – and disseminating it in the public domain and thus for aiding the development of renewable energy.
- Integration of this dataset into EMD services - was co-supported through the InnoWind project (www.innowind.dk) - which is co-funded by the Danish Innovation Fund
External Links
- Geodata from the Wales: http://lle.gov.wales/home
- InnoWind project - http://www.innowind.dk