Satellite Imagery and Lidar Data for Efficiently Describing Structures and Densities in Residential Urban Land Uses Classification

Urban areas are complicated due to the mix of man-made features and natural features. A higher level of structural information plays an important role in land cover/use classification of urban areas. Additional spatial indicators have to be extracted based on structural analysis in order to understand and identify spatial patterns or the spatial organization of features, especially for man-made feature. It’s very difficult to extract such spatial patterns by using only pixel-based approaches. Sections of building occupation densities which are integral parts of other uses may be difficult to identify. A lot of public resources have been directed towards seeking to develop a standardized classification system and to provide as much compatibility as possible to ensure the widespread use of such categorized data obtained from remote sensor sources. The definition of “building densities”, for example, includes those uses similarly classified. This paper examines the utility of high-resolution remote sensing image and airborne laser altimetry data for mapping residential land uses within the spatial limits of Barcelona City Council (Spain). It was possible to discriminate different densities of residential development, and to separate these from commercial/industrial and agricultural areas. Difficulties arose in the discrimination of lowdensity residential areas due to the range of land cover types within this specific land use, and their associated spatial variability. The greater classification errors associated with these low-density developed areas were not unexpected. It was found that these errors could be mitigated somewhat with techniques that consider the mode of training data selection and by incorporation of methods that account for the presence and amount of impervious surfaces. This paper focuses on a methodology developed based on the pixel-based approach and three dimension analysis of artificial and residential areas. The combination of high spatial resolution airborne LiDAR and SPOT imagery offers great application opportunities, especially in the urban areas. Since residential urban areas are complicated, a comprehensive approach is needed and different setting have to be investigated to cope with different type of urban areas and to different type of cities. * Corresponding author.