The Research Three-dimensional Digital Terrain Mapping Technology

In this paper, three areas that three-dimensional digital terrain map of related concepts, methods of data collection and three-dimensional digital terrain mapping were studied. The data acquisition methods of three-dimensional digital terrain map: data collection of digital photogrammetric, data collection of total station and three-dimensional airborne laser scanning system. the various methods of data acquisition principles, error sources and accuracy of analysis were analysed, on the basis of comparative study and analysis of the characteristics of a variety of acquisition methods and applications. Second, this article is also for the three-dimensional digital terrain symbols of the design of a simple programming based on VBA, three-dimensional digital topographic map was drawed under CAD, which three-dimensional digital terrain mapping were studied.Research showed that:â‘ The main field of ground-based measurements using total stations, the accuracy of 0.5-0.75mm, the method is relatively time-consuming, costly and very difficult for large-scale and small-scale region, the detailed planning and engineering design.â‘¡T he accuracy digital photogrammetry is in 0.6-0.8mm., This method of data collection is faster and relatively high costs for small-scale and large regional projects.â—‹3 The accuracy of SAR radar method is 0.25mm, fast acquisition, the cost is very high and the scope of application of high-resolution data acquisition.â—‹4 The accuracy of airborne laser scanning system is 0.5mm, high cost and high resolution for a diverse range of engineering design and terrain mapping.In this paper, an area of Jinan, Data acquisition the total station test and the area of three-dimensional digital terrain mapping are working, and analysing terrain map of the superior defect of three-dimensional digital mapping.