This work addresses the use of remote sensing imagery to quantify the built environment and its spatial and temporal changes. It identifies the building footprint map, building location map, and built-up area map as information products that can be used to quantify physical exposure, one of the variables required in disaster risk assessments. The paper also reviews urban land use maps and urban classes in land cover maps as potential source for deriving exposure information. The paper focuses on the latest generation of satellite borne remote sensing imaging systems that deliver high resolution optical imagery able to resolve buildings and other three dimensional man made constructions. This work also reviews the semantics, the spatial unit used to define physical exposure, image processing procedures and change techniques.