Remote sensing: land cover

Land cover is an intrinsic element of most remote sensing analysis. An obvious example is the use of remotely sensed imagery for straightforward land cover classification (Franklin and Wulder, 2002; Alvarez et al., 2003). Less obvious, perhaps, is the role of land cover in disease mapping (Tran et al., 2002) or climate change studies (Kalluri, 2002). The reason land cover has such a key position in the field of remote sensing relates to the way remotely sensed data are acquired. Remote sensing involves measuring electromagnetic radiation (commonly, reflected sunlight) from features on the Earth’s surface (Aplin, 2003). Land-based features may be categorized according to land cover classes (e.g., grass, concrete, water, etc.) (Smith et al., 2003), and since different land cover features reflect radiation in different ways, remotely sensed images provide a basic representation of land cover variation on the Earth’s surface. Even where land cover information is not the ultimate goal of remote sensing studies, it is often a useful aid for further analysis. Given this importance of land cover to the field of remote sensing and, in particular, the many physical geographical applications of remote sensing, this Progress Report will focus on recent developments in land cover research. In general, there are two main areas of remote sensing-based land cover research, (1) environmental management and (2) environmental understanding. Environmental management refers to the control and use of land cover distributions to exploit land resources while safeguarding environmental concerns. Environmental understanding refers to the scientific analysis of processes (both natural and those caused by humankind) involved in determining land cover. Each of these general research areas is discussed in turn but, given that there is considerable overlap between environmental management and environmental understanding, some general points are made that refer to both topics. Initially, reviews of recent developments in land cover classification and land cover change lead into discussions on environmental management and environmental understanding. Finally, a brief summary of general developments in the field of remote sensing is provided.