General
The New Zealand Land Cover Database (LCDB) is a digital map of the surface of New Zealand created using satellite imagery. It contains detailed information on categories of land cover and their boundaries and is a record of land cover changes over time. Two editions of the New Zealand Land Cover database have been completed (LCDB-1 and LCDB-2). These show the state of New Zealand’s land cover in 1996-1997 and in 2000-2001 respectively. LCDB-1 used SPOT 2 and SPOT 3 satellite imagery to resolve 16 land cover classes (Table 1). LCDB-2 was released in 2004 and used LANDSAT 7 ETM+ satellite imagery and the thematic classification was increased to 43 classes (Table 2). The increased thematic depth of LCDB-2 reflected the superior spectral resolution of the LANDSAT 7 sensor but many users observed a decline in classification accuracy. While both LCDB-1 and LCDB-2 included automation in their image preparation and early classification stages, both were primarily reliant, in their later stages of compilation, on visual inspection of imagery and manual digitizing. A further two editions of the LCDB will be produced under the current LCDB programme contract, and it is envisaged that future funding will be found for development beyond this.
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LCDB-1 |
LCDB-2 |
LCDB-3 |
LCDB-4 |
| Base imagery date |
1996-97 |
2000-01 |
2008 |
2012 |
Release date
|
June 2000 |
2004 |
June 2012 |
June 2014 |
| Predominant imagery |
SPOT 2 and SPOT 3 |
Landsat 7 ETM+ |
SPOT |
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| Lead agency |
Terralink |
Terralink |
Landcare |
Landcare |
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Thematic detail
LCDB-2 classes were designed to provide backward comparability with the earlier LCDB-1. Some of these classes proved to be unreliable to distinguish or less important for end use applications. The LCDB-3 classes resulted from a sequence of user forums conducted in 2010 and aims to address some of the issues with the LCDB-2 set while still maintaining comparability.
Land Cover classifications
of LCDB1 and LCDB2 and that of the proposed LCDB3
|
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LCDB-1
(16
classes)
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LCDB-2
(43
classes)
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LCDB-3
(33, rationalised LCDB-2)
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Artificial Surfaces
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Urban Area
Urban Open Space
Mines and Dumps
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Built-up Area (settlement)
Urban Parkland/Open Space
Surface Mine
Dump
Transport Infrastructure
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Built-up Area (settlement)
Urban Parkland/Open Space
Surface Mines and Dumps
Transport Infrastructure
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Bare or Lightly-vegetated Surfaces
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Coastal Sand
Bare Ground
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Coastal Sand and Gravel
River and Lakeshore Gravel and Rock
Landslide
Alpine Gravel and Rock
Permanent Snow and Ice
Alpine Grass/Herbfield
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Coastal Sand and Gravel
River and Lakeshore Gravel and Rock
Landslide
Alpine Gravel and Rock
Permanent Snow and Ice
Alpine Grass/Herbfield
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Water Bodies
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Inland Water
Coastal Wetland
Inland wetland
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Lake and Pond
River
Estuarine Open Water
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Lake and Pond
River
Estuarine Open Water
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Cropland
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Primarily Horticulture
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Short-rotation Cropland
Vineyard
Orchard and Other Perennial Crops
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Short-rotation Cropland
Orchard Vineyard & Other Perennial Crops
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Grassland, Sedgeland and Marshland
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Primarily Pastoral
Tussock Grassland
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High Producing Exotic Grassland
Low Producing Grassland
Tall Tussock Grassland
Depleted Grassland
Herbaceous Freshwater Vegetation
Herbaceous Saline Vegetation
Flaxland
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High Producing Exotic Grassland
Low Producing Grassland
Tall Tussock Grassland
Depleted Grassland
Herbaceous Freshwater Vegetation
Herbaceous Saline Vegetation
Flaxland
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Scrub and Shrubland
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Scrub
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Fernland
Gorse and or Broom
Manuka and/or Kanuka
Matagouri
Broadleaved Indigenous Hardwoods
Sub Alpine Shrubland
Mixed Exotic Shrubland
Grey Scrub
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Fernland
Gorse and/or Broom
Manuka and/or Kanuka
Broadleaved Indigenous Hardwoods
Sub Alpine Shrubland
Mixed Exotic Shrubland
Grey Scrub
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Forest
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Planted Forest
Major Shelterbelts
Willows and Poplars
Indigenous Forest
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Minor Shelterbelts
Major Shelterbelts
Afforestation (not imaged)
Afforestation (imaged, post LCDB1)
Forest - Harvested
Pine Forest - Open Canopy
Pine Forest - Closed Canopy
Other Exotic Forest
Deciduous Hardwoods
Indigenous Forest
Mangrove
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Exotic Forest
Deciduous Hardwoods
Indigenous Forest
Mangrove
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The rationalised classification means that, for example,
mines will not be distinguished from dumps as they are in LCDB-2 and the
age-class breakdown of exotic forests (of interest largely to the forestry
industry) will not be maintained. A map-to-image automated change detection process is being used to highlight areas for operator investigation.. This detection method often highlights errors present in LCDB-1 & 2 and correction of these errors is part of the LCDB-3 mapping process.
A stakeholder check and revision
process will be developed in consultation with the Governance Group and
contributing stakeholders. This will allow stakeholders to contribute to a
schedule of field checking and revision of a draft version of each new LCDB
edition. Key stakeholder groups with knowledgeable field staff who have
indicated support for this process include Regional Councils, Rural Fire
Authorities and Dept of Conservation. By LCDB-5, field devices and the rural
reach of mobile data networks are expected to be able to support an entirely
on-line process for requesting field checking and revision. Through LCDB-3 and
LCDB-4 online processes will be progressively developed and deployed to support
this mode of operation, but it is recognised that support for off-line field
processes will also be needed.
The core products of this work, subject to changes agreed
with the Governance group will be :
- A database of nominally 2008 Land Cover (LCDB-3):
- Incorporating:
- LCDB-1/2 boundaries for areas of no detected change
- New (LCDB-3) boundaries for areas of detected change
- Correction in LCDB-1/2 class where error is notified or noticed during difference detection
- LCDB-1/2/3 classifications for all polygons
- An accuracy assessment to quantify the error in the LCDB-3 databases.
- Constrained by:
- An insensitivity to change within major structural groups within which a spectral discrimination is constrained. For example, indigenous forest and some scrub classes
- A database of nominally 2012 Land Cover (LCDB-4):
- Incorporating:
- LCDB-1/2/3 boundaries for areas of no detected change
- New (LCDB-4) boundaries for areas of detected change
- Correction in LCDB-1/2/3 class where error is notified or noticed during difference detection
- LCDB-1/2/3/4 classifications for all polygons
- An accuracy assessment to quantify the error in the LCDB-4 database.
- Constrained by:
- An insensitivity to change within major structural groups within which a discrimination is constrained.
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