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The Civil Engineering and Development Department (CEDD) of the Government of the Hong Kong Special Administrative Region (HKSAR) has recently completed its first territory-wide airborne Light Detection and Ranging (LiDAR) survey. The survey is primarily intended to obtain detailed topographical information to support natural terrain hazard assessment. The technology employed is capable of recording reflected signals from the natural hillside below vegetation cover, which can be used for deriving high-resolution ground profiles and digital terrain models for mapping landslides and other landform features. The LiDAR data are also being used for other applications such as urban planning, flood analysis and aviation controls in Hong Kong.

Over 6,000 million data were collected over Hong Kong with over 6,000 field test points confirming a vertical data accuracy of about 3cm root mean square (rms) on clear flat ground. Apart from describing the administrative and technical issues of the survey, especially those for the densely populated urban environment of Hong Kong, this paper also outlines a number of the geotechnical applications being used by the CEDD, including identification of relict landslides, change detection of topography after landslides and delineation of anthropogenic features.