STUDY ON DETERIORATION OF HISTORIC MASONRY IN THE FORBIDDEN CITY IN BEIJING AIDED BY GIS

Abstract. The Forbidden city in Beijing is one of the first culture heritage to be listed as UNESCO World Heritage in 1987. The mass and complexity of this imperial palace brings challenges to scientific surveys and documentations. This graduation project adopted the technology of GIS to record, evaluate and analyze historic masonry and their deteriorations across the palace. Aided by ArcGIS, the deterioration degree of every accessible masonry element was accurately and efficiently evaluated and recorded, as well as connected to its precise location among the Forbidden City. All accessible masonry elements in Forbidden City were divided into different types as buildings, walls, foundations, and stairs. The common deteriorations of masonry in Forbidden City were defined and graded according to their degree of severity so that the deterioration was quantified, and a database was established. Before the survey, the mechanism of masonry deterioration in the Forbidden City was presumed to be related to several possible factors. Adopting ArcGIS to set up a database enabled to visualize the distribution of masonry deterioration in the site and lead to a preliminary conclusion, as well as a further mathematic analysis of the data to better understand the cause of deterioration.