3D Terrain Surface Optimization Method Based on Local Curvature Entropy and Quadtree Structure

Abstract

The invention provides a three-dimensional terrain curved surface optimization method based on the local curvature entropy and a quadtree structure, and the method comprises the steps: taking scattered point cloud data with the ground surface elevation attributes as a data source; carrying out the subdividing of regular grid node elevation attributes through employing an IDW method, and carrying out the interpolating calculation; taking the local curvature entropy as the measurement basis for the subdividing of a grid; taking a largest boundary grid of input data as the root nodes of a quadtree; carrying out the recursion judgment of the quadtree in a depth-first mode; carrying out the quartering of the grid which meets the conditions; enabling the quartered grid to serve as child nodes of a current node and to be added to the quadtree, and obtaining an LOD model based on the quadtree structure until all nodes meeting the subdividing condition are completely judged; making the most of the advantages of rapid traversal of the quadtree structure, updating the tree structure through judging the relation between the father and child nodes on a tree, and achieving the elimination of gaps between adjacent grids with different details.

Description

technical field [0001] The invention relates to a method for optimizing a three-dimensional terrain surface based on local curvature entropy and a quadtree structure, and belongs to the fields of three-dimensional graphics and three-dimensional digital terrain modeling. Background technique [0002] Terrain 3D visualization modeling and real-time expression technology is one of the core technologies in the field of geographic information technology, and also one of the key and basic technologies for the construction of 3D geographic information systems. The digital expression of terrain usually adopts digital elevation model (Digital Elevation Model, referred to as DEM), which is a solid ground model that expresses ground elevation in the form of a set of ordered numerical arrays, and is a mathematical expression of terrain undulations. [0003] DEM can be divided into two categories according to the way of sub-domain division: regular grid and irregular triangular grid. Re...

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Problems solved by technology

However, since the curvature can only represent the terrain details of a certain point, the sensitivity is high

If the curvature is directly used as the subdivision evaluation standard, the transition between terrain hierarchical grids will be very jumpy, and the level of detail of adjacent grid blocks may be very different, especially in flat areas, which are prone to oversimplification. The distribution of the simplified terrain surface is uneven, resulting in discontinuity and incompleteness in the browsing process of the terrain model

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