Development of building height data in Peru from high-resolution SAR imagery

Building data, such as footprint and height, are important information for pre- and post-event damage assessments when natural disasters occur. However, these data are not easily available in many countries. Because of the remarkable improvements in radar sensors, high-resolution (HR) Synthetic Aperture Radar (SAR) images can provide detailed ground surface information. Thus, it is possible to observe a single building using HR SAR images. In this study, a new method is developed to detect building heights automatically from two-dimensional (2D) geographic information system (GIS) data and a single HR TerraSAR-X (TSX) intensity image. A building in a TSX image displays a layover from the actual position to the direction of the sensor, because of the side-looking nature of the SAR. Since the length of the layover on a ground-range SAR image is proportional to the building height, it can be used to estimate this height. We shift the building footprint obtained from 2D GIS data toward the sensor direction. The proposed method was applied to a TSX image of Lima, Peru in the HighSpot mode with a resolution of about 1 m. The results were compared with field survey photos and an optical satellite image, and a reasonable level of accuracy was achieved.