Abstract: In the process of old residential area reconstruction, it is necessary to extract the information data of external structural surface and internal structural surface of residential buildings. Aiming at the problems of traditional surveying and mapping methods such as heavy workload, high cost and long period, this paper takes an old residential area reconstruction project of a customs building in Honghe prefecture of Yunnan province as an example, based on the point cloud data obtained by three-dimensional laser scanning technology, scans the building's external facade, internal structure of stairs and roof. Based on Leica Cyclone software, we carry out experimental research on point cloud data registration, filtering and denoising, and data hierarchical management. After integrating point cloud data, it has drawn the facade, section and plan of the old building with CAD software, and checked and evaluated the measurement accuracy and accuracy of the scanning results with traditional measurement methods such as total station and distance meter. The average accuracy of the two-dimensional mapping can reach to 1.54 cm. The research results show that 3D laser scanning technology can obtain 3D point cloud data of field data, completely record all data forms of the field with high-density, high-precision, high-quality point cloud data, and has a complete solution for data acquisition and mapping of the subsequent old community reconstruction project.

Key words: 3D laser scanning, reconstruction of old communities, point cloud data, two-dimensional mapping scheme, data processing