基于DEM的网络3D GIS地形关键数据提取和还原方法研究

发布时间：2018-07-09 22:30

本文选题：地形特征点 + 关键地形数据点　；参考：《沈阳工业大学》2013年硕士论文

【摘要】：地理信息系统的显示已经开始从二维符号向三维图形转化。三维地理信息系统能够在空间进行数据的分析和管理，能够以人的视角来模拟、分析、管理和表示真实的空间事物，可以使人们能够和更加真实的模拟三维世界进行各种交互。但是，，网络三维地理信息系统除了包含符号描述的地理信息还涉及到大量的描述地理信息的栅格数据，其中大量的三维地形数据是地理信息显示的基础，因此大量的三维地形数据在网络三维地理信息系统中的传输就成为一个主要问题。通过对基于格网的模型简化技术的研究，发现在三维地形数据中有一些关键的数据点，它们在格网简化时起了重要作用。因此，把模型简化思想运用到三维地形数据的传输，即把关键的数据点提取出来传输到客户端，在客户端恢复三维地形数据，再建立三维模型。因此本文主要研究了如何提取关键的三维地形数据点，以及依据这些数据点如何近似还原的三维地形数据并生成三维地形。关键的三维地形数据点包括三维地形模型中描述地形特征，如山峰、山谷点、山脊点、洼地点、鞍部点等地形特征的数据点；以及对地表形态有较大影响作用的重要地形数据点。针对地形特征点采用基于坡度和曲率的方法进行提取；对地形起伏变化有较大影响的重要地形点，依据用坡度、坡度变化率，采用典型的基于最大坡降的算法和基于差分的算法分别进行重要地形数据点的提取，并对以上两种算法进行了讨论和分析。由于DEM描述的三维地形数据是基于规则网格数据，因此在客户端依据插值算法可以计算出未被提取的网格数据点的高程实现三维地形数据的还原，建立三维地形模型。因为采用上述的一系列算法实现对地形数据的提取和还原是有损的，所以针对还原后的数据进行误差分析。最终通过实验验证了该算法的可行性。
[Abstract]:The display of GIS has begun to transform from two-dimensional symbols to three-dimensional graphics. 3D GIS can analyze and manage the data in space, simulate, analyze, manage and express the real spatial things from the perspective of human, and enable people to interact with more realistic simulation of 3D world. However, Web 3D GIS not only contains symbolic description of geographic information, but also involves a large number of grid data describing geographic information, in which a large amount of 3D terrain data is the basis of geographic information display. Therefore, the transmission of a large amount of 3D terrain data in the network 3D GIS becomes a major problem. Based on the research of model simplification technology based on grid, it is found that there are some key data points in 3D terrain data, which play an important role in mesh simplification. Therefore, the idea of model simplification is applied to the transmission of 3D terrain data, that is, the key data points are extracted and transmitted to the client, the 3D terrain data is recovered at the client side, and the 3D model is established. Therefore, this paper mainly studies how to extract the key 3D terrain data points, and how to approximate restore the 3D terrain data and generate 3D terrain data according to these data points. The key 3D terrain data points include the data points which describe the terrain features in the 3D terrain model, such as mountain peak, valley point, ridge point, depression point, saddle point and so on. And the important topographic data points which have great influence on the surface morphology. The method based on slope and curvature is used to extract the topographic feature points, and the important terrain points which have great influence on the variation of topographic undulation, according to the slope, the rate of slope change, The typical algorithms based on the maximum slope gradient and the algorithm based on difference are used to extract the important topographic data points, and the above two algorithms are discussed and analyzed. Because the 3D terrain data described by Dem is based on regular grid data, the elevation of unextracted grid data points can be calculated on the client side according to the interpolation algorithm, and the 3D terrain model can be established. Because it is harmful to use the above algorithms to extract and restore the topographic data, the error analysis of the restored data is carried out. Finally, the feasibility of the algorithm is verified by experiments.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P208

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