Quantitative assessment of LiDAR dataset for topographic maps revision

Abstract

Topographical map production is a tedious process, where it involves flight planning for the aerial photographic mission, preparation of ground control points, photogrammetric processes and cartographic activities. The task is time consuming, labour intensive and costly. With the vast development of the Klang Valley in Malaysia, customary revision of the topographic maps using the conventional method is expensive. At present, LiDAR (Light Detection and Ranging) technology is able to suffice accurate 3D (three dimensional : x, y, z) points of the earth surface in short delivery time. In this study, the possibility of LiDAR dataset (Digital Surface Model) as an important source of information towards topographic maps revision will be investigated. The study area comprises of an undulating topography situated at Melawati in the Klang Valley region, Malaysia, covering an area of one square kilometer. The accuracy of the derived LiDAR dataset both in vertical (RMSEz) and horizontal (RMSExy) components were quantified. Furthermore, the accuracy for the published topographic maps at the scale of 1:10 000 and 1:50 000 were also investigated in both components. The results obtained are then compared with the specification published by the Malaysian Map Accuracy Standards. It were found that, the vertical (RMSEz) accuracy achieved were ±0.21m, ±1.94m and ±6.88m for LiDAR dataset, topographic maps at the scale of 1:10 000 and 1:50 000 respectively. Where else, for the horizontal component (RMSExy), the accuracy estimates derived were found to be ±0.51m, ±1.33m and ±11.63m for the mentioned dataset respectively.