ZHANG Jinghua , FENG Zhiming , JIANG Luguang
Land cover; Land use; Classification system; Land use and land cover change
Land use and land cover change (LUCC) is one of the most important aspects within the scope of global change. As a critical portion of LUCC study, classification of land use and land cover types not only affects the classification results, but also determines applications of relevant data. In the paper, studies of land use and land cover classification systems were reviewed. It could be concluded that the land use and land cover classification laid more emphasis on the land use classification before the 1970s. The land use classification system emphasized the differences between land functions and was mainly applied to land use inventory investigation and land use mapping. After then, the classification system based on land cover rapidly developed due to the development of satellite remote sensing and computer technology. This classification system emphasized the differences between land categories and was mainly applied to land cover change studies. The review shows that almost all current land use and land cover classification systems tend to be suitable only for a specific research purpose at a certain scale. The incompatibility amongst the current classification systems has resulted in numerous inconveniences and difficulties in the courses of aggregation, analysis, and sharing of land use and land cover data due to the absence of consistent standards. Therefore, a standardized classification system is extremely warranted. However, a universal classification system suitable for all kinds of research purposes is neither possible nor necessary. The reasons lie in that on the one hand, the minimum classification unit could be dependent on the mapping scale as well as the spatial resolution of remote sensing data; on the other hand, land use and land cover types of varying detailed degrees are required for different research purposes. Furthermore, it would be probable that some special land use and land cover types existed in specific regions, for example, the Qinghai-Tibet Plateau in China. At last, this review states that a standardized classification system should be hierarchically organized and could be extended. The land use and land cover types of higher hierarchy could be directly identified from remote sensing images without auxiliary information, which would make it convenient for data comparison and sharing. The land use and land cover types of lower hierarchy could be defined in terms of a specific study purpose, which could satisfy the specific study needs.