International Symposium and Exhibition on Geoinformation 2009. August 10-11, 2009 The Potential of High Density Scanner Technique for Terrestrial Surface Displacement Studies in Malaysia Z. Othman 1 , R. K. Azahari 1 , C. H. Rozaimi 1 , M.S. Rahim 2 , M.Y.M. Khairani 2 , M. Faizah 2 , Y.W.Chien 2 1 Department of Civil Engineering, College of Science and Technology, Universit i Teknologi Malaysia, Jalan Semarak 54100 Kuala Lumpur, Malaysia, Email: othman08@ic.utm.my 2 Department of Surveying and Mapping, Nat ional Land and Surveying Inst itut e, Behrang, 35950 Tanjong Malim, Perak, Malaysia,Email: rahim@instun.gov.my Abstract – High Densit y Scanner, as a technology, has gone through an impressive development phase. The development of High Density Scanner (HDS) for the generation of Digital Terrain Model (DTM) has made great progresses in objects measuring, reaching high resolutions and completeness in models reconstruction. Nowadays it is an essential tool that can be used to detect, to better classify and to monitor Terrestrial Surface Displacement (TSD). When studying terrestrial surface displacement, it becomes important to utilize quantitative techniques to develop metric multi temporal 3D models of the TSD and its surroundings. Malaysia is one of the country that facing a lot of TSD event every year especially in the rainy season. Several surveying methodologies are used to investigate the activity of existing TSD: point based (Total Station, GPS) and area based techniques (Photogrammetry and Remote Sensing). The advent of affordable High Density Scanner has opened up a new opportunity in rapid TSD modeling. HDS technology is a surveying method conceived more than ten years ago that in a short time can supply DSM (Digital Surface Model) and good quality DTM as a result of elaborations with specific filtering and interpolation algorithms; only recently has this technique shown growth in development and applications. The objective of this paper is to find the applicability of High Density Scanner (HDS) for Terrestrial Surface Displacement (TSD) studies. A working group consisting of staff from University Technology Malaysia (UTM) International Campus Kuala Lumpur and National Institute of Land and Survey (INSTUN), Behrang, Perak has being setup to carry out t his study. The research area is located wit hin the confinement of INSTUN. Keywords : Terrestrial surface displacement; High Density Scanner; Digital Terrain Model I. Introduction In recent years, Malaysia facing a lot of landslides event especially after the heavy rains. Frequent occurrences of landslides at those areas during the rainy/ monsoon seasons (November – February) have resulted in public fear for the safety of their life and properties. This phenomenon has been accelerated by the rapid development especially at hilly terrain, construction of highways, mining activities, riverbank instability, etc. Since 1970 until 2007, more than 300 landslides occurred throughout Malaysia and more t han 40 landslides event have been report in Klang, Valley especially at the hilly terrain resident area - see [13]. This makes, landslides monitoring techniques an important study subject for the related professional disciplines in Malaysia. A landslide is a general term given t o describe the various forms of mass movement such as down-slope movement of soils, rocks and organic materials under the influence of gravity force. Landslide can be trigger by gradual processes such as weathering or external mechanisms, for examples, undercutting of slope erosion, intense rainfall or sharp fluctuations in ground levels, loading on upper slope, etc. Landslides occur when a portion of a hill slope becomes too weak to support its own weight. This weakness is initiated when rainfall or some other sources of water increases the water content of the slope, reducing the strength of the materials. The raised water table after a rainstorm would saturate the soil rendering it weak and therefore the slope failure would naturally occur due to gravitational forces. They become a problem when they interfere