1 The Effect of Changing Grid Size in the Creation of Laser Scanner Digital Surface Models

Raw laser scanning data are captured and supplied as 3D points. These point data require an appropriate interpolation function to be applied to them in order to represent a continuous height surface. Many software packages require that points be interpolated onto a regular grid, in order that the resultant surfaces can be displayed as a Digital Surface Model (DSM). Such interpolation procedures introduce error across the surface, and these errors will be accommodated by any subsequent analysis on the DSM, such as image segmentation or feature extraction. Whilst it is generally understood that interpolation introduces error, there is a paucity of information regarding the characteristics of the errors created using different methodologies. Out limited understanding of the magnitudes and the spatial structure of errors creates uncertainty for users of derived products, such as the Digital Elevation Mode