3D Terrain Visualisation for GIS: A Comparison of Different Techniques

Geographic Information System (GIS) applications are now moving towards 3D as it has a better representation of the real world. Most GIS applications now can be visualised not only in 2D but also in 3D. Currently most of the applications are capable of operating in an online environment such as Google Earth, Microsoft Virtual Earth and World Wind. Recently, many people use these online applications for their daily work and also for decision making. Terrain visualisation is an important aspect for these three applications, in visualizing the world in 3D. The quality of terrain visualisation depends on the techniques used by the developer. The research for generating good quality terrain visualisation for depicting the real world is ongoing and faces big challenges. There are many techniques available that can be used to visualize the terrain in 3D such as photorealistic and non-photorealistic rendering (NPR). The aim of this paper is to compare different techniques of terrain visualisation in GIS environment. The techniques involved in this experiment are colour shading, terrain overlaid with satellite image and silhouette rendering algorithm for NPR. The comparison is based on the quality of terrain visualisation, representation of object on terrain, representation of slope, and error in terrain. Three different areas in the Universiti Putra Malaysia (UPM) were chosen for this experiment; grid Digital Elevation Model (DEM) generated from R2V software was used as topographic data and Quick Bird satellite image of UPM for satellite data. Each of the areas was tested by the three different techniques of terrain visualisation. The results from these different techniques of terrain visualisation are discussed in detail. The results of this paper will be of help to the users in identifying the best technique of terrain visualisation suitable for GIS data.