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Abstract
Land cover changes in the urban area of Western Sydney are analysed based upon the interpretation of two Landsat 5 images for 1989 and 2008. The project addresses three research questions: (1) what is the distribution of land cover types? (2) How complex is the urban landscape of Western Sydney? (3) What are the change dynamics and driving forces of land cover change?
In order to answer the above questions, two thematic classification maps are produced in ERDAS IMAGINE by the maximum likelihood supervised classification method. After generating a land cover conversion matrix, one observes that mixed land cover has increased by 6289.74 ha, of which 5022.54 ha was converted from green areas. Three landscape-related factors were identified that influenced this change to mixed land cover: the degree of terrain slope, distance from the centre of an LGA, and distance to the road network. The analysis of the amount of area that has experienced changes identified three factors as being influential: (1) the steeper the slope is, the fewer mixed land cover changes incurred; (2) the further the distance to an LGA centre and to the road network, the more mixed land cover changes were incurred; (3) the urban expansion incurred surrounding the existing urban area.
A total of 13 landscape metrics were calculated using FRAGSTATS, and assessed by principal components analysis (PCA) with the aid of the R software package. Three landscape metrics captured most of the variability of the landscape pattern: patch shape index (SHAPE), patch area index (AREA), and edge contrast index (ECON). The analysis of these metrics and the three factors mentioned above shows: (1) a general relationship between change in slope and changes to the landscape metrics; (2) the patch size tends to be smaller and the patch shape tends to be regular with closer distance to the centre of an LGA and to the road network; (3) the area that is closer to the centre of an LGA and to roads becomes less fragmented, because the land was subdivided and the patches tend to coalesce. The study demonstrates that by combining remote sensing technology, GIS software and landscape metrics some useful approaches to land cover change analysis can be developed that assist in understanding the growth pattern of an urban area.