RECORDING INFORMATION ON ARCHITECTURAL HERITAGE SHOULD MEET THE REQUIREMENTS FOR CONSERVATION Digital Recording Practices at the Summer Palace

Abstract. The recording of Architectural heritage information is the foundation of research, conservation, management, and the display of architectural heritage. In other words, the recording of architectural heritage information supports heritage research, conservation, management and architectural heritage display. What information do we record and collect and what technology do we use for information recording? How do we determine the level of accuracy required when recording architectural information? What method do we use for information recording? These questions should be addressed in relation to the nature of the particular heritage site and the specific conditions for the conservation work.

In recent years, with the rapid development of information acquisition technology such as Close Range Photogrammetry, 3D Laser Scanning as well as high speed and high precision Aerial Photogrammetry, many Chinese universities, research institutes and heritage management bureaux have purchased considerable equipment for information recording. However, the lack of understanding of both the nature of architectural heritage and the purpose for which the information is being collected has led to several problems. For example: some institutions when recording architectural heritage information aim solely at high accuracy. Some consider that advanced measuring methods must automatically replace traditional measuring methods. Information collection becomes the purpose, rather than the means, of architectural heritage conservation.

Addressing these issues, this paper briefly reviews the history of architectural heritage information recording at the Summer Palace (Yihe Yuan, first built in 1750), Beijing. Using the recording practices at the Summer Palace during the past ten years as examples, we illustrate our achievements and lessons in recording architectural heritage information with regard to the following aspects: (buildings’) ideal status desired, (buildings’) current status, structural distortion analysis, display, statue restoration and thematic research. Three points will be highlighted in our discussion:

1. Understanding of the heritage is more important than the particular technology used: Architectural heritage information collection and recording are based on an understanding of the value and nature of the architectural heritage. Understanding is the purpose, whereas information collection and recording are the means.

2. Demand determines technology: Collecting and recording architectural heritage information is to serve the needs of heritage research, conservation, management and display. These different needs determine the different technologies that we use.

3. Set the level of accuracy appropriately: For information recording, high accuracy is not the key criterion; rather an appropriate level of accuracy is key. There is considerable deviation between the nominal accuracy of any instrument and the accuracy of any particular measurement.