The characterisation and measurement of land cover change through remote sensing: problems in operational applications?

Abstract

This paper examines issues surrounding the detection, measurement and characterisation of landscape changes by remote sensing and other means. First it compares the remotely sensed Land Cover Map of Great Britain (LCMGB), 1990, with the UK Land Cover Map 2000 (LCM2000). Then it considers the more general circumstances where users compare any two thematic maps incorporating independent inaccuracies, to record changes. The paper concludes that the measurement of small to medium scale changes over large areas requires levels of precision in mapping which are near impossible to achieve with satellite image classifications alone; indeed they may be difficult to achieve in any form of survey unless it is tailor-made and rigorously applied specifically to the recording of real changes. The paper argues that users of all such data products therefore need to treat with extreme caution their maps of differences and their conclusions about change. It suggests that users need also to develop intelligent approaches, which draw upon a broader knowledge of the directions, patterns and scale of the changes to be recorded, in order to refine their assessments.