OSGB格式三维模型投影坐标转换方法

Projected coordinate transformation method of 3D model in OSGB format

在倾斜摄影测量领域,ContextCapture和其它商业软件对以多套投影坐标系交付三维模型的支持并不完善。在对OSGB格式三维模型目录和文件结构进行系统分析的基础上,提出一种简单易行的投影坐标转换方法,先使用OSG获得待转换模型的顶点及中心坐标,再进行投影坐标转换并偏移,之后先在OSGB文件数据流中检索转换前坐标的位置,最后将转换前坐标替换为转换后坐标。基于该方法开发的软件运行速度快,转换后的模型显示准确、无变形、无闪烁。该方法很容易扩展到其它三维模型格式。

In the field of oblique photogrammetry,the support of ContextCapture and other commercial softwares to deliver 3D models in multiple projected coordinate systems is not ideal.Based on a systematic analysis of the directory and file structure of 3D model in OSGB format,this paper proposes a simple and easy method of projected coordinate transformation.Firstly,OSG is used to obtain the vertex or center coordinates of the nodes,and then the projected coordinates are transformed and offset.Finally,the position of original coordinates is retrieved in the binary data stream,and then the original coordinates are replaced by the converted coordinates.The coordinate transformation software developed based on this method runs fast,and the transformed model displays accurately without deformation and flicker.This method can be easily extended to other 3D formats.