All Wales Phase 1 Terrestrial - Vegetation Layer - Voronoi

This is a GIS dataset containing spatial polygons showing the boundaries and attributes of vegetation polygons.

A voronoi procedure was applied to the All Wales Phase 1 Terrestrial - Vegetation Layer - GIS dataset to subdivide upland mixed habitat polygons into their component habitats as identified by the All Wales Phase 1 Terrestrial - Habitat Layer - GIS dataset. New polygons derived by the voronoi procedure have Voronoi_UID's prefixed 'v_'. New polygons created from Habitat Layer points mapped with a string of habitats, e.g. D.1.1 + D.2/E.2.1, are attributed 'mosaic' in the Phase 1 Code field, and the component habitats and their proportions are listed in the Mosaic browser table (see metadata for All Wales Phase 1 Terrestrial - Mosaic Layer voronoi - GIS dataset). The two tables link on the Voronoi_UID field. 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.

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 mapping of 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 in the vector data.

Identifier: NRW_DS115875

Alternative Title

Phase 1 Vegetation voronoi.lyr

Metadata Language: English

Lineage: Voronoi procedure carried out on the cleaned version of the vegetation layer (see metadata for Terrestrial Phase 1 Habitat Survey).

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. All field mapping was carried out by trained and closely co-ordinated teams of surveyors. 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 habitats that tend to occur in small patches such as upland flush and upland species-rich ledges may be over-estimated by the voronoi procedure.

Additional Information: Voronoi maps are constructed from a series of polygons formed around the location of a sample point. Voronoi datasets form a derived mosaic allowing statistically derived polygons to be created from point data.

Dataset Reference Date (Publication): 2014-11-20

Temporal Extent

Begin date: 1979-01-01

End date: 1999-12-31

Topic category

Biota
Environment
Farming

Owner

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Originator

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Extent

Geographic Extent: Wales (WLS)

Format Type and Description

Geographic Information System ( )

Specification

ESRI Feature Class

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
Degree: false

Lineage: Voronoi procedure carried out on the cleaned version of the vegetation layer (see metadata for Terrestrial Phase 1 Habitat Survey).

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. All field mapping was carried out by trained and closely co-ordinated teams of surveyors. 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 habitats that tend to occur in small patches such as upland flush and upland species-rich ledges may be over-estimated by the voronoi procedure.

Keywords

GEMET - INSPIRE themes, version 1.0

Habitats and biotopes

Type: Theme

Citation

Date (Publication): 2008-06-01

Code: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus

lowlands
Phase 1 Habitat Survey
future of the uplands

Type: Theme

Citation

Date (Publication): 2024-06-19

Code: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Code: British National Grid (EPSG::27700)

Content Information

NRW Profile

Custom Elements

NRW Related Title: Upland vegetation survey 1979-1989 : background, methodology and summary of data collected

NRW Related Title: Supplementary notes for phase 1 survey in Wales

NRW Related Title: An assessment of errors in Phase I habitat survey in Wales. Confidential

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

File Identifier: 4f4c4942-4343-5764-6473-313135383735 XML

Metadata Language: English

Parent Identifier: Terrestrial Phase 1 Habitat Survey
NRW_DS24715

Resource type: Dataset

Metadata Date: 2024-07-30T12:59:37.218Z

Metadata Standard Name: NRW

Metadata Standard Version: 1.0

pointOfContact

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Publishing Body

Access the portal

Full access to the portal and metadata.

All Wales Phase 1 Terrestrial - Vegetation Layer - Voronoi

Identification

Temporal Extent

Extent

Extent

Distribution

Quality

Data quality

Keywords

Keywords

Citation

Keywords

Citation

Spatial Reference System

Content

Content Information

NRW Profile

Custom Elements

Constraints

Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

Use Constraints

Attribution Statement

Licence

Metadata

Metadata

Publishing Body