Slope gradient analysis at different resolution using terrestrial laser scanner

Slope instability in landslide prone area is a costly problem, which can lead to travel disruption, property damages, and injury or loss of life. For many years, slope monitoring activities are largely carried out by conventional survey instruments such as Total Station, levelling and Global Positioning System (GPS). However, these techniques is a time consuming, hazardous, and costly process, and it can be difficult to ensure that problems are recorded and handled in a consistent manner. Terrestrial laser scanners (TLS) find rapidly growing interest in remote sensing and photogrammetry field as efficient tools for fast and reliable three-dimensional (3D) point cloud data acquisition. The TLS technology is based on the reflectorless and contactless acquisition of a point cloud of the topography using the time-of-flight distance measurement of an infrared laser pulse. This paper describes the capabilities of TLS in slope mapping studies. The main objective of this study is to evaluate the slope mapping pattern at different resolution. This study has been conducted at Cameron Highland, Malaysia, which approximately located at latitude 4d26\´36" and longitude 101d23\´4". Several data acquisitions on selected cut slopes were performed using the Topcon GLS1500 laser scanner. Ground control points were established using Real Time Kinematic GPS to provide a local coordinate system on laser scanning data. Resolution of a laser scanner determines a density of point cloud during data acquisition. In this experiment, there is a different number of resolution has been set during data acquisition in order to evaluate the result of slope mapping pattern. It was found that, resolution gives an effect in slope mapping pattern.