You must remember the Beijing Declaration approved by the ISPRS 2008 Congress. It calls on international communities to work together and commit adequate resources to promote the peaceful use of geospatial technology for the benefit of society and the environment. Now I am pleased to tell you that a very successful investigation and mapping of the Ming Great Wall have been completed recently with the help of digital photogrammetry and aerial imageries.
"How long is China's Great Wall"His a question asked for about five hundreds years. One of the reasons is that some parts of the Great wall were built on the mountainous areas and traditional field surveying could not measure its real length in 3d space. 1:35,000 air photos were used to generate the 3D digital models of Ming Great Wall and its slope length was measured with digital photogrammetric tools. About 800 professionals from geomatics and cultural heritage disciplines participated the project. On the April 18, 2009, it was revealed that the Great Wall in the Ming Dynasty era stretched 8,851.8 km, further than the previous estimate of around 6,000 km. It has an artificial wall of 6259.6 kilometers, 359.7 kilometers of trench wall, and 2232.5 kilometers of natural defensive barriers such as hills and rivers.
As the result of two year's through investigation, all the important items of the heritage of Great Wall have been surveyed and image maps at 1:10,000 scale covering the stripe of Ming Great Wall have been produced. A special GIS is now under development by integrating the results of heritage investigation with geo-spatial database. It will be used as an operational system in the protection, research and sustainable development of the world Heritage site.
As the chief scientist of this mapping project, I am very proud of the successful application of imagery in mapping large scale world cultural heritage, and the fruitful collaboration between Geomatics and cultural heritage disciplines. As there are many other ongoing or completed projects about peaceful application of geo-spatial technology, I hope to share experiences with you in ISPRS sponsored events in the near future. The mid-term symposia of ISPRS eight technical commissions in 2010 will certainly provide us good opportunities to report our works and to exchange ideas. Please visit ISPRS website and you will find the information about these mid-term symposia.
Chen Jun
ISPRS secretary General