Method for generating variable resolution digital elevation model

Abstract

The invention relates to a method for generating a variable resolution digital elevation model. The method comprises the following steps of: establishing an east-north-sky right-handed coordinate system according to a measured topographic region, establishing a new plane coordinate system X'O'Y' in an XOY plane by using a measurement station point as a center, and establishing a polar coordinate system by using the original point of the new plane coordinate system as a pole and the direction far away from the center of the measurement station point as a polar axis; acquiring a three-dimensional data discrete point of the measured topographic region under the east-north-sky right-handed coordinate system; determining an angle sampling range in the polar coordinate system according to the measured topographic region, setting angle sampling intervals, and calculating the quantity of elevation sampling points required in the angle range; determining a radial sampling range along each angle direction, determining radial sampling change rates and sampling intervals, and calculating the quantity of the elevation sampling points required in the radial direction; and acquiring polar coordinates of all the elevation sampling points within the angle sampling range and the radial sampling range, constructing an irregular triangulation network according to the data discrete point, and calculating through interpolation to obtain elevation values of all the elevation sampling points. The method can be widely applied to data storage and expression during topographic and geomorphic measurement.

Description

technical field [0001] The present invention relates to a method for generating a digital elevation model, in particular to a variable-resolution digital elevation model that is suitable for expressing a digital elevation model obtained by close-range photogrammetry or ground laser scanning and that can maintain the different elevation accuracy of the original terrain generate method. Background technique [0002] A digital elevation model (DEM) is a digital representation of a terrain surface using a set of ordered terrain sampling points. Digital elevation models commonly used in the prior art include regular grid (Grid) and irregular triangular network (TIN). The regular grid is to divide the coverage area of ​​the digital elevation model into regularly arranged square grids, store the elevation value at the center point of each grid, and record the position of the starting point and the grid spacing, then the plane position of any grid point It can be obtained by calcu...

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Problems solved by technology

[0003] When using close-range photogrammetry or terrestrial laser scanning to measure terrain, the accuracy of terrain measurement varies with distance in a certain way. The farther away from the measurement point, the lower the accuracy of terrain measurement. The terrain accuracy can be expressed as an accuracy standard, which cannot be changed according to the level of terrain accuracy. The irregular triangulation only records the elevation of some discrete points, and the resolution has no rules to follow. Neither of them can be effectively expressed by using close-range photogrammetry or Characteristics of Terrain Data Acquired by Terrestrial Laser Scanning

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