Research On Sampling Method To Improve Accuracy Of Strip Digital Terrain Model

Digital Terrain Model (DTM) is a way of digitized presentation for terrain information, DTM suited for railway engineering is called strip digital terrain model, it is foundation and core to locate railway line by computer, Engineers can locate best line project easily and design automatically for horizontal plane, vertical plane, cross-section of railway line in office.The most important thing making use of DTM is to guarantee validity; the accuracy of DTM is degree of approximation of DTM'surface and actual terrain surface. It mainly depends upon original data sampling error and DTM model error. Under the condition of fixed DTM software and sampling method, the distribution and density of sampling points is critical factor to accuracy of DTM.In order to study the regularity of distribution and density of sampling points to accuracy of DTM, some data trails are done to seek regularity of different sampling methods for typical terrain. Leading jobs are: select typical terrain, topographic map digitizing, sampling, forming triangular irregular network, height interpolation, evaluation of accuracy and so on. Based on these trails, some useful conclusions are put forward to improve the accuracy of DTM for TIN. The conclusion provides reference for topographic map digitizing and forming high-accuracy DTM, and also for digital mapping.