Monitoring landscape change in Kathmandu metropolitan region using multi-temporal satellite imagery

摘要

The increasing availability of time series satellite images and improving techniques have allowed mapping and detecting landscape change in densely populated and topographically complex urban areas. This research aims to trace land use patterns and spatiotemporal landscape change in Kathmandu metropolitan region for the last five decades. Incorporating with other ancillary data, the CORONA (1967), Landsat (1978, 1991, and 2000), and ALOS (2010) satellites images were processed applying hybrid image classification method. Twelve land use types were mapped. Dynamic spatial patterns of urban landscape are observed where the built-up areas gradually increased in the 1970s but had a speedy growth since the 1990s. Prime agricultural landscape in the valley floor has been converted to built-up areas. Forest and shrubs landscapes in rural areas are mostly changed to agricultural uses. Expansion of built-up area has progressively become uniform in recent decades. A refill type of development in the city core and adjacent areas has shown a decreasing trend of the neighborhood distances and an increasing trend of physical connectedness between the different land uses. This process indicates a higher probability of homogenous landscape development particularly built area in upcoming decades which may further degrade the urban ecosystem services and cause environmental problems in the metropolitan region.