The Antiquities and Monuments Office has been working on both photographic and surveying records of historic buildings of outstanding heritage value in Hong Kong. These records document the existing physical condition of historic buildings, which will provide reference for the restoration works in the future. Using scientific methods, we survey buildings, analysing the original architectural design, including its structure, details and proportion, and precisely recording the survey results in image format. A complete set of measured drawings are prepared, with location plan, floor plan, roof plan, elevation drawing, cross-sectional drawing and a large-format detailed plan. Occasionally, stereoscopic imagery is used to show a perspective view of the building. The drawings are a valuable resource for studying Hong Kong's architectural development, heritage and history, fostering awareness of historic buildings among both the public and scholars.

Measured drawings were prepared manually in the early days. As technology advanced, state-of-the-art surveying instruments and computer software were used, reflecting the transformation of surveying and drawing technology. In recent years, the recording technology for historic buildings has evolved from two-dimensional photo images and drawings to three-dimensional laser scanning. This enables much faster and more accurate recording of spatial information of historic buildings in exhaustive detail, and the efficient transformation of the relevant survey data into measured drawings and three-dimensional models, which provides great help in the research, conservation and promotion of historic buildings.