Application of Land Use Changes Detection for Identification of Landslide Risk Areas in Pulau Penang using A Decade of Landsat 7 ETM+ Images

Abstract

Landslide has been one of major natural threats in Penang Island, Malaysia. Rapid urban development and crop land expansion have encroached forest areas. Both activities are believed to have contributions to slope instability that can lead to landslide events. Using a decade of Landsat 7 ETM+ images, from 1999-2009, detection of land use changes can be carried out. This paper investigates the relation between land use changes and landslide sites. The images were subset to conform to main island of Penang Island state. Dark object correction, histogram equalizes, and histogram matching were applied to the images to remove atmospheric effect. Image to image registration was selected as geometric correction method by which the first image acquired in 27 December 1999 was used as a reference image. Normalized Difference Vegetation Index (NDVI), Tasseled Cap Transformation (TCT) and Principal Component Analysis (PCA) images were derived from corrected images. As for land use change detection technique, the image subtraction method was selected. Land use change detection was based on difference of multi date of NDVI, TCT, PCA and panchromatic images. As the final stage, detected land use changes were overlaid with landslide and hill project maps. As the result, most of landslide sites were located at changed areas as well as the hill project. NDVI and TCT greenness-based change detection gave better identification of changed areas followed by PC1, panchromatic and TCT-wetness