Accuracy evaluation for large-scale map using modern geospatial tools

Abstract

With the advancement of recent technologies, various methods have evolved in response to the rising demand for 2-D/3- D mapping in Geographical Information Systems (GIS). Although there are different traditional methods for 3-D mapping, they are time-consuming, provide low accuracy, and involve complex processes. Therefore, point cloud data technology based on laser and photo scanning is gaining popularity in 3-D mapping data on construction sites. Preparing a 3-D map with more details requires a high-quality laser scan with greater accuracy. The purpose of this study is to prepare the 3-D map and assess and compare the horizontal and height accuracy of point, line, or polygon features using a Total Station (TS)/Smart Station (SS), Differential Global Positioning System (DGPS), and Terrestrial Laser Scanner (TLS). Furthermore, the accuracy provided by the tools used has been assessed for 2-D/ 3-D mapping at large scales, such as 1:500 or 1:1000. The coordinates for the polygon feature, line feature, and point feature were measured using DGPS, Smart Station, and TLS. The comparative planimetric and height accuracy of georeferenced point cloud data collected using TLS has been compared with SS and DGPS data collected from the field survey. The outcome of the present study demonstrated that the horizontal and vertical accuracy of 1 mm and 33 cm for horizontal and vertical had been achieved using a terrestrial laser scanner compared with the smart station, while comparing smart station with differential global positioning system, the observed differences is 1 mm in horizontal and maximum of 12.0 m in vertical measurements. Finally, the overall expended time on the reference network using SS consumed more data acquisition and post-processing time i.e., about 2 hours 30 minutes, than other advanced instruments, such as DGPS and TLS.