ghg-inventory-1990-2013

The potential woody change layers were visually checked to confirm change and then the
changes were combined with the 2001 reference layer to create the 1990 and 2008 woody
land cover layers. Area and proximity rules were used to convert these layers from woody
land cover to woody land use, making allowances for unstocked areas within forest
extents and areas of regenerating shrubland in a forest context. This process is described
in Shepherd and Newsome (2009a).
To determine the spatial location of the other land-use categories and subcategories as at
1990 and 2008, information from two Land Cover Databases, LCDB1 (1996) and
LCDB2 (2001) (Thompson et al, 2004), hydrological data from Land Information
New Zealand (a government agency) and the New Zealand Land Resource Inventory
(NZLRI) (Eyles, 1977) was used (Shepherd and Newsome, 2009b).
The NZLRI database defined the area of high and low producing grassland. Areas tagged
as ‘improved pasture’ in the NZLRI vegetation records were classified as high producing
grassland in the land-use maps. All other areas were classified as low producing
grassland. Figure 6.2.1 illustrates this mapping process.
Figure 6.2.1
New Zealand’s land-use mapping process
Note:
LINZ = Land Information New Zealand.
An interpretation guide for automated and visual interpretation of satellite imagery was
prepared and used to ensure a consistent basis for all mapping processes (Ministry for the
Environment, 2012). Independent quality control was performed for all mapping. This
206 New Zealand’s Greenhouse Gas Inventory 1990–2013