Comparative Study on Methods For 3D Modelling with Traditional Surveying Technique and Total Station Technique

Abstract

Three-dimensional modelling of the natural surface of the Earth is very important in understanding the irregularities of the Earth surface. It is a vital tool in planning large development projects such as designing of high ways, airports, hydropower plants, reservoirs; building sites etc. Two technical approaches are being used for the above task in conventional land surveying. The first step is to carry out horizontal surveying and producing a survey plan which depicts the horizontal projection of the area of interest. The second step is to carry out levelling in order to obtain heights with reference to datum over evenly spread grid points covering the required area. With the introduction of Electro-Magnetic Distance Measurements, a new equipment known as total station is available for land surveyors to capture three dimensional coordinates of points on the ground. This new technology is comparatively much faster than the conventional two-fold technique of collection of horizontal coordinates through surveying and obtaining heights through levelling. This research paper evaluates accuracies of conventional surveying and levelling methodology and the modern Electro-Magnetic Distance Measurements. It also compares the precision of the output of the conventional surveying contour plan and the digital terrain model empirically and statistically in order to evaluate pros and cons of conventional and modern surveying techniques. For this evaluation, a total station and an automatic level was used to survey the study area, employing both methods and analysing data from each method empirically, statistically and comparing the outcome of aforesaid methods. After the analyses of data it was revealed that both techniques are comparatively equal in precision but the total station is far more efficient than the conventional surveying and levelling method. The final outcome of the study is that the total station is more suitable for an engineering survey done for general purposes. Keywords