All Wales Phase 1 Terrestrial - Mospolys Layer voronoi
This is a spatial dataset of Phase 1 mosaic polygons. The polygons are a grid of squares coloured in chequerboard fashion according to Phase1_Code and in proportion to their extent to enable the visualisation of mosaics in a GIS. The mosaic polygons were created by the NRW Phase 2 Tools from the All Wales Phase 1 Terrestrial - Vegetation Layer - Voronoi - GIS dataset and the All Wales Phase 1 Terrestrial - Mosaic Layer Voronoi - GIS dataset.
The original field surveys were carried out as part of a national habitat survey programme required to implement conservation at a local level. An all-Wales 1km square dataset was created for the generation of national statistics on habitat coverage, and the maps were digitised as part of the project to map Open Access land. The dataset was subsequently imported into a GIS to enable its disaggregation into various different geographical regions within Wales. Voronoi was carried out to enable full representation and visualisation of the components of complex mixed-habitat upland polygons.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS116722
- Alternative Title
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- Phase 1 Mospolys voronoi.lyr
- Metadata Language
- English
- Lineage
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Voronoi procedure carried out on the cleaned version of the vegetation layer, and mosaic browser created from this.
Closely co-ordinated teams of surveyors carried out field recording of habitats onto 1:10,000 scale maps (rarely 1:25,000 during the upland stage). The minimum size of habitat patch recorded lies predominantly within the range 0.1-0.25 ha, although smaller areas were mapped in the lowlands. The survey methods employed during the initial upland stage are given in more detail in a WFU report (Day, A. (1989) Upland Vegetation Survey 1979-1989 Background Methodology and Summary of Data Collected. NCC, Bangor). Methods for the lowland survey followed the Handbook for Phase 1 Habitat Survey with some minor modifications adopted for use in Wales (Howe E.A. and Blackstock T.H. (1991) Supplementary Notes for Phase I Survey in Wales. CCW, Bangor).
The voronoi procedure was carried out in MapInfo to split complex upland mixed habitat polygons into component parts using a tool written in-house by the GIS and Spatial Data Team within NRW. A study of survey reliability was conducted during the lowland phase (Kerry, Rimes, Smith, Williams. 1994. An Assessment of Errors in Phase I Habitat Survey in Wales. Bangor: Countryside Council for Wales, Report No. 94/4/1). It showed the field mapping to be 83% repeatable (Stevens, Blackstock, Howe, Stevens. 2004. Repeatability of Phase 1 habitat survey. J. Environ. Manage. 73, 53-59). The electronic data have undergone a series of checks for accuracy both by the contractor and subsequently within CCW. The extent of upland flush and upland species-rich ledges may be over-estimated by the voronoi procedure.
- Dataset Reference Date (Publication)
- 1997-12-31
Temporal Extent
- Begin date
- 1979-01-01
- End date
- 1997-12-31
- Topic category
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- Environment
Extent
Extent
- Geographic Extent
- Wales (WLS)
))
Distribution
- Format Type and Description
-
-
Geographic Information System
(
)
- Specification
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ESRI Feature Class
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Geographic Information System
(
)
Quality
Data quality
- Quality Scope
- Dataset
- Lineage
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Voronoi procedure carried out on the cleaned version of the vegetation layer, and mosaic browser created from this.
Closely co-ordinated teams of surveyors carried out field recording of habitats onto 1:10,000 scale maps (rarely 1:25,000 during the upland stage). The minimum size of habitat patch recorded lies predominantly within the range 0.1-0.25 ha, although smaller areas were mapped in the lowlands. The survey methods employed during the initial upland stage are given in more detail in a WFU report (Day, A. (1989) Upland Vegetation Survey 1979-1989 Background Methodology and Summary of Data Collected. NCC, Bangor). Methods for the lowland survey followed the Handbook for Phase 1 Habitat Survey with some minor modifications adopted for use in Wales (Howe E.A. and Blackstock T.H. (1991) Supplementary Notes for Phase I Survey in Wales. CCW, Bangor).
The voronoi procedure was carried out in MapInfo to split complex upland mixed habitat polygons into component parts using a tool written in-house by the GIS and Spatial Data Team within NRW. A study of survey reliability was conducted during the lowland phase (Kerry, Rimes, Smith, Williams. 1994. An Assessment of Errors in Phase I Habitat Survey in Wales. Bangor: Countryside Council for Wales, Report No. 94/4/1). It showed the field mapping to be 83% repeatable (Stevens, Blackstock, Howe, Stevens. 2004. Repeatability of Phase 1 habitat survey. J. Environ. Manage. 73, 53-59). The electronic data have undergone a series of checks for accuracy both by the contractor and subsequently within CCW. The extent of upland flush and upland species-rich ledges may be over-estimated by the voronoi procedure.
Keywords
Keywords
- Type
- Theme
Citation
- Date (Publication)
- 2008-06-01
Keywords
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NRW Thesaurus
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- upland vegetation
- vegetation surveys (vegetation monitoring)(see also biologicalsurveys)
- Habitat Survey of Wales
- habitat surveys (habitat monitoring)
- vegetation (see also specific types eg.coastal or heathland vegetation and vegetation surveys)
- Phase 1 Habitat Survey
- Upland vegetation Survey
- Phase 1 Survey (Phase I)
- Type
- Theme
Citation
- Date (Publication)
- 2024-06-19
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
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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There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Use Constraints
- Use constraints type
- Other restrictions
- Other constraints
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© CNC/NRW All rights Reserved. Contains Ordnance Survey Data. Ordnance Survey Licence number AC0000849444. Crown Copyright and Database Right Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and copyright of the owners. It is the recipient's responsibility to ensure the data is fit for the intended purpose.
Attribution Statement
- Other constraints
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Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Contains Ordnance Survey Data. Ordnance Survey Licence number AC0000849444. Crown Copyright and Database Right.
Licence
- Other constraints
- Open Government Licence
Metadata
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313136373232 XML
- Metadata Language
- English
- Parent Identifier
-
Terrestrial Phase 1 Habitat Survey
NRW_DS24715
- Resource type
- Dataset
- Metadata Date
- 2024-08-01T15:00:26.199Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
-
1.0