All Wales Phase 1 Terrestrial - Mosaic Layer Voronoi
This dataset is a GIS browser table that contains information on the habitats present and their proportions and areas in mosaic polygons. This method of dealing with mosaics is based on the approach used for mosaics in Phase 2 vegetation survey GIS datasets.
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 and the mosaic browser lists habitats in mosaic polygons and gives proportions and area data.
Habitat mixtures were treated as equal splits, e.g. D.1.1 and E.2.1 in the string 'D.1.1 + E.2.1' were allocated proportions 1 : 1, and mosaics were treated as subsidiary divisions, e.g. the components of the string 'D.1.1 + D.2/E.2.1' were allocated proportions 2 : 1 : 1. Habitats in brackets were allocated proportions of 2 percent. The Phase 2 Tools were used to create a mospolys (mosaic polygons) layer to which the Phase 1 legend can be applied for better visualisation in GIS.
- Identification
- Extent
- Distribution
- Quality
- Keywords
- Spatial Reference System
- Content
- Constraints
- Maintenance
- Metadata
Identification
- Identifier
- NRW_DS115876
- Alternative Title
-
- Phase 1 Mosnotes voronoi.lyr
- Phase 1 Mospolys voronoi.lyr
- Metadata Language
- English
- Lineage
-
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)
- 2014-11-20
Extent
Extent
- Geographic Extent
- Wales (WLS)
))
Distribution
- Format Type and Description
-
-
Geographic Information System
(
)
- Specification
-
[A] GIS layers in MapInfo tab. Format
-
Geographic Information System
(
)
Quality
Data quality
- Quality Scope
- Dataset
- Conformity
- Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
- Explanation
-
This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
- Degree
- false
- Lineage
-
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
-
NRW Thesaurus
-
- Phase 1 Habitat Survey
- future of the uplands
- lowlands
- Type
- Theme
Citation
- Date (Publication)
- 2024-06-19
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
- NRW Related Title
-
Handbook for phase 1 habitat survey : a technique for environmental audit. Field Manual
- NRW Related Title
-
Handbook for phase 1 habitat survey : a technique for environmental audit
- NRW Related Title
-
Upland vegetation survey 1979-1989 : background, methodology and summary of data collected
- NRW Related Title
-
An assessment of errors in Phase I habitat survey in Wales. Confidential
Constraints
Constraints
Limitations on Public Access and Use
- Restriction type
- Other restrictions
Access Constraints Directive
- Limitations
- no limitations
Access Constraints Text
- Other constraints
-
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
-
© 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
-
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
- 4f4c4942-4343-5764-6473-313135383736 XML
- Metadata Language
- English
- Parent Identifier
-
Terrestrial Phase 1 Habitat Survey
NRW_DS24715
- Resource type
- Dataset
- Metadata Date
- 2025-02-04T10:10:35.774Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
-
1.0