New Zealand’s Land Use and Carbon Analysis
(LUCAS) releases latest land use data

New Zealanders will now be able to download the latest land use data following the completion of a major mapping exercise by the Ministry for the Environment.

The integrated land use map (LUM), which provides an in-depth snapshot of land use in New Zealand from 1990-2008, has been produced as part of the Land Use and Carbon Analysis System (LUCAS).

Users of the LUM will be able to:

• Measure changes in land uses between 1990 and 2008.
• Assess the relationship between land use and pressures on freshwater systems as a result of these changes.
• Use the data as an evidence-base for academic research projects.
• Use data as a base on which to overlay operational data to help shape decisions and policies.

LUM was derived from satellite imagery provided to government agencies as a result of an all-of-government licence negotiated by the Ministry for the Environment.

The data is available now for electronic download from www.koordinates.com, a geospatial data distribution site.

The land use map data has been issued with a Creative Commons Attribution licence that requires users to acknowledge the Crown as the original source of the data, with no restrictions on its use, re-use and right to share.

Steve Botica, manager of the Ministry’s LUCAS programme, said the data will encourage the free exchange of environmental data, allowing more people access, use and benefit from the information purchased by government.

“Improving access to the government’s spatial information is a goal of the New Zealand Geospatial Strategy. This approach also supports the NZ Government Open Access and Licensing (NZGOAL) framework.

“LUM was specifically developed to meet our Kyoto Protocol reporting requirements and, therefore, is different from the previously produced Land Cover Databases 1 and 2. I would encourage people to review the contextual material provided with the maps to ensure they gain a good understanding of the scope for LUM.”

Q What is LUM 1990-2008?
LUM 1990-2008 is a spatial database which contains land use attributes as at 1 January 1990 and 1 January 2008. The definition of each land use class is provided in the illustrated guide that is available for download along with the data.

Q. How was LUM 1990-2008 developed?
The LUM as at 1990 is derived from semi-automatic classification of 30 m spatial resolution Landsat 4 and Landsat 5 satellite imagery taken in, or close to, 1990. The first of the images used were taken in November 1988 and the last in February 1993.

The LUM as at 2008 was derived from semi-automatic classification of 10 m spatial resolution SPOT 5 satellite imagery. The SPOT 5 imagery was taken over the summers of 2006-07 and 2007-08 (November to April), to establish a national set of cloud-free imagery. Where the SPOT 5 imagery pre-dates 1 January 2008, a combination of aerial photography and field verification was used to identify where deforestation has occurred to ensure that the 2008 land-use map is as accurate as possible.

Q. What other datasets were used in the mapping process?
The semi-automated classification of satellite imagery primarily separates areas covered with woody vegetation from those without (in this case, planted forest, natural forest, and scrub or grassland with woody biomass). Therefore, in order to take advantage of existing information some land use classes were drawn from LCDB1, LCDB2, the Land Resource Inventory and Land Information New Zealand hydrological data.

The NZLRI database was used to define the area of high and low-producing grassland. Areas tagged as ‘improved pasture’ in the NZLRI vegetation records were classified as grassland – high producing in the land-use maps. All other areas were classified as grassland – low producing. Other datasets used in decision making include 15m resolution Landsat 7 ETM+ imagery acquired in 2000-2001, and SPOT 2 and 3 data acquired in 1996-1997.

Q. What is the difference between LCDBs and LUM 1990-2008?
LUM was produced to meet international reporting requirements under Article 3.3 of the Kyoto Protocol and therefore uses international definitions of land use.

Land cover mapping depicts features that physically exist on the surface. In other words, they show what you would see in an aerial photograph or satellite image.

Land use can be different from the physical land cover but can be inferred from the land cover. For example, an area with a land cover classification of bare earth may be recently harvested forest. In this case, the land cover is bare earth whereas the land use is forestry. LCDB2 contained a combination of land use and land cover, but LUM 1990-2008 is derived on the basis of land use.
These differences mean that in many instances, the polygon boundaries in the LUM will not necessarily match LCDB polygon boundaries.

Q. How accurate is the LUM 199-2008?
Under the LUCAS programme, the target classification accuracy is 95 percent. At this stage, accuracy assessment has not yet been undertaken. However, LUM-1990-2008 mapping data have been independently checked to determine the level of consistency in satellite image classification to the requirements set out by the Ministry. Through this process, approximately 28,000 randomly-selected points in the 1990 and 2008 woody classes were evaluated by independent assessors. From this exercise, 91 per cent of the time, independent assessors agreed with the original classification.

Q. How often will LUM 1990-2008 be updated?
Under the Kyoto Protocol Article 3.3, New Zealand is required to establish three sets of maps to determine land use and land use change between 1990 and 2008, and subsequently between 2008 and 2012. This means there will be another mapping exercise to establish a 2012 land use map. In the interim, there will be annual updates to improve the maps and identify land use changes such as deforestation.

Q. What do I need to do to download the LUM?
Simply visit http://koordinates.com/#/maps/environment/ to view and download LUM and all the other datasets released by Ministry for the Environment. You have 3 options to get LUM data. You can select and area of interest or the entire dataset. If you have a particular area of interest simply click on the “crop” button at the bottom of the webpage and drag over the area you are interested in. This will place a square over your area of interest. When you are ready to proceed, click the green “download or order” button. You will then be presented with options to either download or to order a delivery on DVD. You also need to select the data output format, map projection file type. Note that the entire LUM dataset is approximately 1.2gigabytes in zip format and about 1.9 gigabytes when you unzip it. It is highly recommended that you use the “crop” function or order data on DVD for a small fee.

ENDS

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