Land-use Change

Urbanization requires conversion of land from agricultural to urban uses, a process well illustrated at Bayan Lepas, Penang Island, Malaysia. In 1969, paddy fields and quiet farm villages covered the land along the road leading to the airport. Today, Bayan Lepas is Malaysia's "Silicon Valley".

Study Aim and Research Strategy

This study documents change in land use in the Bayan Lepas area of Penang Island from 1969 to 2003.

The main objectives were to make and compare two maps of land use, the first using a topographic map based on a 1969 survey, the second using a set of satellite images acquired in 2003 by the ASTER instrument aboard Terra, a NASA satellite.

Land-use features were confirmed and photographed during field visits. The study suggests the kind of irrigation system in place in 1969 and reveals the extent of land reclamation since then, neither of which was known to the author before the study began.

To prepare the 2003 land-use map, the study used all 14 ASTER bands, including visible and near-infrared, infrared, and thermal infrared parts of the spectrum. Composite images and ratio images were prepared to help interpret the land-use map. Variations among these supporting images suggest other processing strategies with potential to improve the quality of land-use classification. Exploration of such strategies could form the basis for future work.

The methodology adopted for this study may be appropriate only because the analyst lacked other means to compare land use in 1969 and 2003. Land-use maps based on topographic maps may be conceptually different from land-use maps based on satellite image.

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