Detailed features of the old Star Ferry pier and clock tower have been recorded and stored as 3D images through an advanced laser scanning technology.

The data enables the Government to consider how to incorporate these special features in the design of the new Central harbourfront.

Collective memory: Civil Engineering & Development Department officers use a laser scanner to scan the old Star Ferry Pier. Chief Land Surveyor Dominic Siu explains the process.

Government departments are also taking photographic records for the pier, which has served Hong Kong for decades.

Civil Engineering & Development Department Chief Land Surveyor Dominic Siu said laser scanning has been used to digitalise detailed information before demolition of the Star Ferry pier to help preserve people's "collective memory".

He said laser scanning can acquire huge amounts of 3D points, or "'point clouds", in a very short time.

Digital record

"Through the point clouds, the scanning system can also measure distances and directions, and produce structural and cross-sectional plans, 3D models and computer flythrough animation, which can unfold concerned buildings from all perspectives. With a record of more than 150 million measured points, details, features and even settings of the pier and the clock tower have been precisely stored in a digital way," he said.

"Different substances have different degrees of reflection intensity. Laser scanning can isolate colours, texture and co-ordinates of buildings. Such data can be saved in an electronic format which enable the Government to consider how to incorporate some special features of the clock tower and the pier in the design of the new Central harbourfront."

Mr Siu said the $2-million laser scanner was purchased by the Civil Engineering & Development Department in 2003, mainly for landslip forensic investigation. The scanner is also used for recording data on monuments or objects aiding historical research.

3D recordings have been made of Lei Cheng Uk Han Tomb, Tai Fu Tai Mansion in San Tin and fire boat Alexander Grantham.