A 3D annotation optimal placement algorithm for the point features in the small scale geographic scene

摘要

? 2016, Surveying and Mapping Press. All right reserved. ? 2016, Surveying and Mapping Press. All right reserved. The 3D annotations placement rules of point features in geographic scene are “obscured then not showing” and “obscured then directly showing” normally. The defects of those rules are annotation information lost or large numbers of occlusion, so their universalities are not strong and they are not suitable for the annotation placement of small-scaled geographic scene. This paper summarizes the contents, position and placement methods of 3D annotation and takes the aim at “not loss of annotation information and less annotation obscured as far as possible” of the research problem of the annotation placement of small-scaled geographic scene. The configuration rule of 3D annotation Identifies as “obscured then optimized to display”. The designed algorithm based on the perspective transformation matrix, the inverse perspective transformation matrix and the grid algorithm takes the genetic algorithm (GA) whose fitness evaluation function uses the 3D Annotation quality evaluation function as the core to realize the feasible optimal solution of 3D annotations of point features in geographic scene. By the multi-views, multi-platforms contrast experiment, this algorithm is applicable for multi-views 3D annotation placement widely. The 3D annotation effect is better than mainstream GIS platforms (such as SuperMap desktop, ArcScene), which assumes that the algorithm's 3D annotation quality value is relatively increased 144%, 232%. The algorithm fits in with the target configuration. The 3D annotations placement rules of point features in geographic scene are “obscured then not showing” and “obscured then directly showing” normally. The defects of those rules are annotation information lost or large numbers of occlusion, so their universalities are not strong and they are not suitable for the annotation placement of small-scaled geographic scene. This paper summarizes the contents, position and placement methods of 3D annotation and takes the aim at “not loss of annotation information and less annotation obscured as far as possible” of the research problem of the annotation placement of small-scaled geographic scene. The configuration rule of 3D annotation Identifies as “obscured then optimized to display”. The designed algorithm based on the perspective transformation matrix, the inverse perspective transformation matrix and the grid algorithm takes the genetic algorithm (GA) whose fitness evaluation function uses the 3D Annotation quality evaluation function as the core to realize the feasible optimal solution of 3D annotations of point features in geographic scene. By the multi-views, multi-platforms contrast experiment, this algorithm is applicable for multi-views 3D annotation placement widely. The 3D annotation effect is better than mainstream GIS platforms (such as SuperMap desktop, ArcScene), which assumes that the algorithm's 3D annotation quality value is relatively increased 144%, 232%. The algorithm fits in with the target configuration.