Three-dimensional map line element note automatic placing method

Abstract

The invention discloses a three-dimensional map line element note automatic placing method, can be applied to automatically placing and adjusting writing nodes in a three-dimensional geographic scene. The method comprises the following stages of 1, pretreatment stage: attaching note reference lines to the surface of the earth, and building a note reference line layered tree structure; 2, a parallel traversal screening stage: dynamically building view point related reference lines, and executing shielded cutting based on a shadow map and monotonicity segmentation of the reference lines; and 3, a screen space note confliction processing stage: projecting the reference lines to a screen space, processing mutual confliction relation between the notes, and generating a renderable note object. By dynamically building the view point related note reference lines, the note automatic placing method can adapt to different view distance and variations of the viewing angle, and reflect the trend of line elements; in addition, shielding of surface features on the notes is avoided due to shielded cutting based on the shadow map, and the problem of confliction between the notes is solved by using a non-backtracking graph coloring algorithm in the screen space.

Description

technical field [0001] The invention belongs to the fields of computer graphics and cartography, and in particular relates to a method for automatically placing annotations of three-dimensional map line elements. Background technique [0002] The current research on map annotation placement has the following aspects: [0003] (1) Two-dimensional map annotation [0004] Christensen et al. summarize approximate algorithms for annotation placement of point features on static maps. DoNascimento et al. proposed a framework for automatic placement of map annotations that supports the combination of human interaction and automation methods, which can make full use of expert domain knowledge, improve the quality of map annotations, and increase the processing efficiency of annotations. Rylov et al. Assessing the quality of map annotation placement in image space according to the homogeneity of the map's background. Wu et al. proposed a grid-based annotation placement method, whic...

AI Technical Summary

Problems solved by technology

[0011] Purpose of the invention: Aiming at the defects of existing 3D map annotation placement methods, the present invention discloses a method for automatically placing annotations of 3D map line elements, which can meet the needs of 3D line elements for expressing the difference level details of their annotation reference lines, Improve the real-time calculation efficiency of annotations placed along the line, solve the problem of occlusion of annotations by ground objects, and enhance the readability of annotations

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