Architectural conservationists will create a 3-D digital replica of a historic area of Shanghai using photo-based modeling technology.

Liantang old town, in Qingpu district, dates back as far as the Spring and Autumn Period (770-476 BC). However, over the years, a large part has disappeared.

As the local government looks to restore the area, experts at Shanghai Jiao Tong University will use old photos and modern technology to create Liantang digitally.

"Part of the core area has been demolished, so we had a talk with the government about using our photo-based modeling techniques to help restore the original appearance of the destroyed buildings," said Cao Yongkang, director of the college's International Research Center for Architectural Heritage Conservation.

Cao's team uses software that analyses old images of structures, as well as shots of the surrounding area as it is today, to produce accurate spatial data that can guide any restoration work. The technology is still in the early stages in China and was first used here in 2001, when the center was asked to help with research into restoring the tomb of Xu Guangqi, a mathematician and scientist in the Ming Dynasty (1368-1644), in Shanghai's Xujiahui area.

Last year, Cao and his team carried out risk evaluations on several structures of cultural significance in the Tibet autonomous region. In addition, the center is creating a database of the information its researchers have discovered about historical buildings.

"Traditionally, this kind of information has been scattered, and it's difficult to share on a large scale," Cao said.

"Our system can improve heritage protection, and we're working toward creating a complete archive."

The center has also established an international education center in Shanghai to further studies into technology for protecting architectural heritage, digital measurement and nondestructive testing, and to raise the technical abilities in China.