Historic Aerial Imagery to Monitor Temporal Change in Intertidal Habitats
Long-term and broad-scale datasets are essential to any investigation of change in natural communities. This dataset includes the collation of aerial imagery for 44 sites around the Welsh coastline, selected to contain rocky shore, saltmarsh or Sabellaria alveolata across temporal scales providing suitable data for comparisons of change through time, both anthropogenic and biological. In order for comparisons to present day imagery, current aerial imagery was also obtained in this study. Photographic aerial images containing features of conservation value (specifically rocky shores, Sabellaria alveolata inhabited shores and saltmarsh areas) within Wales were obtained. Historic photographic aerial images that contained features of conservation value (specifically rocky shores, Sabellaria alveolata inhabited shores and saltmarsh areas) within Wales were selected from expert knowledge and Countryside Council for Wales's collection of habitat maps. The aim of this project was to collate, digitise and georeference aerial photographic imagery for sites that had multi-year overlap. Accuracies of less than 5 m RMS was obtained (with the exception of Treath Lafan, 1995, and the Dyfi Estuary, 1975). At these saltmarsh locations, there were too few ground control points to achieve this accuracy.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS115512
- Alternative Title
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- Delweddau hanesyddol o'r awyr er mwyn arolygu newid yng nghynefinoedd rhynglanwol tros amser
- Metadata Language
- English
- Lineage
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Rocky shores sites included Bull Bay, Cemlyn Bay, Cemaes Bay, Holyhead, Penrhyn (East side of Holyhead bay) and Trearddur Bay. Sabellaria sites included Aberaeron, Mochras and Llanddulas and S. alveolata. Those images remaining as photographic prints were digitised using an Epson GT-15000 scanner at 1200 dots per inch (dpi). Images in adjacent locations were mosaicked with the image panorama generating software Autopano Giga 2.6, with a root mean square error (RMS) of less than 5 m where possible. Aerial images were then georeferenced in ArcMap10.0, using Ordnance Survey maps where features were readily visible both on the map and on the image. On occasion, images were georeferenced using aerial imagery that was already georeferenced. Accuracies of less than 5 m RMS was obtained. Georeferenced images were then rectified with the ArcMap10 Nearest Neighbour (for discrete data) function as uncompressed TIFFs, before compression to JPEG format with 100% image quality. Image clarity and descriptions were given for individual images. Spatial reference for all data is British National Grid. Present-day low-altitude imagery was captured with a time-lapse compact Canon camera (D10) with no flash and infinity focus. The camera was attached to either a kite or a helium balloon and led over the sites of interest. The resultant images were mosaicked with Autopano Giga 2.6 achieving the lowest RMS possible and visual clarity. Ground control points were marked during the aerial fly over with a dGPS (Leica GS50 or Magellan MobileMapper 6). On several occasions, dominant habitat types were also walked round in the field providing habitat ground-truthing, logging polylines in the GPS systems. The data from the GPS systems were post-processed using ephemeris data from a fixed station (Morpeth), to achieve accuracies of less than 1.5 m for ground control points and less than 3 m for walk-around data.
- Dataset Reference Date (Publication)
- 2013-12-31
Temporal Extent
- Begin date
- 1969-01-01
- End date
- 2013-12-31
- Topic category
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- Biota
- Imagery base maps earth cover
))
Distribution
- Format Type and Description
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Geographic Information System
()
- Specification
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[A] Report held within Ffynnon in full and low resolution format - NRW-14-025647, NRW-14-016317. [B] Locations of intertidal historical aerial images based in MapInfo and ArcGIS format. [C] A full set of images that are hled in the Report in JPEG format [D] Historic and current Aerial Imagery from 1992-2013 in JPEG Format
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Geographic Information System
()
Quality
Data quality
- Quality Scope
- Dataset
- Lineage
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Rocky shores sites included Bull Bay, Cemlyn Bay, Cemaes Bay, Holyhead, Penrhyn (East side of Holyhead bay) and Trearddur Bay. Sabellaria sites included Aberaeron, Mochras and Llanddulas and S. alveolata. Those images remaining as photographic prints were digitised using an Epson GT-15000 scanner at 1200 dots per inch (dpi). Images in adjacent locations were mosaicked with the image panorama generating software Autopano Giga 2.6, with a root mean square error (RMS) of less than 5 m where possible. Aerial images were then georeferenced in ArcMap10.0, using Ordnance Survey maps where features were readily visible both on the map and on the image. On occasion, images were georeferenced using aerial imagery that was already georeferenced. Accuracies of less than 5 m RMS was obtained. Georeferenced images were then rectified with the ArcMap10 Nearest Neighbour (for discrete data) function as uncompressed TIFFs, before compression to JPEG format with 100% image quality. Image clarity and descriptions were given for individual images. Spatial reference for all data is British National Grid. Present-day low-altitude imagery was captured with a time-lapse compact Canon camera (D10) with no flash and infinity focus. The camera was attached to either a kite or a helium balloon and led over the sites of interest. The resultant images were mosaicked with Autopano Giga 2.6 achieving the lowest RMS possible and visual clarity. Ground control points were marked during the aerial fly over with a dGPS (Leica GS50 or Magellan MobileMapper 6). On several occasions, dominant habitat types were also walked round in the field providing habitat ground-truthing, logging polylines in the GPS systems. The data from the GPS systems were post-processed using ephemeris data from a fixed station (Morpeth), to achieve accuracies of less than 1.5 m for ground control points and less than 3 m for walk-around data.
Keywords
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2008-06-01
Keywords
- NRW Thesaurus
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- sabellaria alveolata
- polychaete worms
- honeycomb worm
- rocky shore
- coastal habitats (see also specific habitat: saltmarsh,sanddune,maritime heath)
- saltmarsh (salt-marsh) (salt marsh)
- imagery
- photographs (images)
- satellite images
- Type
- Theme
Citation
- Date (Publication)
- 2023-12-31
Keywords
- SeaDataNet Parameter Discovery Vocabulary
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- Habitat extent
- Type
- Theme
Citation
- Date (Revision)
- 2021-01-06
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
- NRW Related Title
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Historic aerial imagery to monitor temporal change in intertidal habitats
Constraints
Constraints
Limitations on Public Access and Use
- Restriction type
- Other restrictions
Access Constraints Directive
- Limitations
- no limitations
Access Constraints Text
- Other constraints
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The following data is considered OS derived data and is therefore jointly owned by NRW and the Ordnance Survey. NRW may release, publish or disseminate this data freely; providing recipients are made aware of use restrictions (See general use restrictions).
Use Constraints
- Use constraints type
- Other restrictions
- Other constraints
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© CNC/NRW and © Crown copyright 2013. All rights reserved. Natural Resources Wales, AC0000849444 Third parties seeking to re-use this data require a Licence issued by NRW. It allows re-use, reproduction and dissemination in any format or medium but only for non-commercial purposes, according to the terms and conditions of the Licence. Those seeking commercial re-use require a commercial licence available from the OS.
Metadata
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313135353132 XML
- Metadata Language
- English
- Resource type
- Dataset
- Metadata Date
- 2024-12-09T14:34:45.527Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
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1.0