Mapping urban impervious surfaces of Nanjing from the dense Landsat imagery

The marked expansion of the urban impervious surfaces induced by continuous growth of economy and population of China over the past three decades has posed a variety of challenges to studies on urban hydrology, climatology and urban planning practice. Thanks to the characteristics of objectivity, efficiency and integrity, remote sensing has been recognized as a powerful alternative for dynamic monitoring impervious surfaces in the context of urbanization, compared to the conventional field survey, which is time-consuming, costly and labor-intensive. Linear spectral unmixing analysis built upon the selected and refined endmembers following the Vegetation-Impervious-Soil (V-I-S) model was applied to the dense Landsat observations consisting of images from approximately biennial and triennial time steps for the time period 1992 to 2011 to extract impervious surfaces information. Results suggested that the imperviousness increased year by year and a radiating sprawl of the imperviousness was witnessed in Nanjing. The recorded changes in the impervious surfaces were principally driven by Nanjing's urbanization processes, demographic pressure and political factors. In this paper, we found the effectiveness and reliability of linear spectral unmixing analysis contributing to the dense mapped changing profiles of the imperviousness will provide insights, implications for subsequent urban environmental studies and also act as a reference for other similar cities when pursuing a sustainable urban management.