城市大比例尺地形图测绘主要采用全野外数字化测量方法,效率低、劳动强度大。随着无人机倾斜摄影测量技术的飞速发展,采用该技术开展大比例尺地形图测绘成为探索和试验的热点课题。利用无人机倾斜摄影成果——数字正射影像和实景三维模...城市大比例尺地形图测绘主要采用全野外数字化测量方法,效率低、劳动强度大。随着无人机倾斜摄影测量技术的飞速发展,采用该技术开展大比例尺地形图测绘成为探索和试验的热点课题。利用无人机倾斜摄影成果——数字正射影像和实景三维模型数据,采用二三维联动一体化测量软件,实现地理要素的测绘和更新。以济南市商河县老城区30 km 1∶500比例尺地形图更新为例,总结该技术应用于大比例尺地形图测绘的技术流程和技术优势。展开更多
A real-time algorithm for constructing contour maps from grid DEM data is pre-sented.It runs completely within the programmable 3D visualization pipeline.The interpolation is paralleled by rasterizer units in the grap...A real-time algorithm for constructing contour maps from grid DEM data is pre-sented.It runs completely within the programmable 3D visualization pipeline.The interpolation is paralleled by rasterizer units in the graphics card,and contour line extraction is paralleled by pixel shader.During each frame of the rendering,we first make an elevation gradient map out of original terrain vertex data,then figure out the final contour lines with image-space processing,and directly blend the results on the original scene to obtain a final scene with contour map using alpha-blending.We implement this method in our global 3D-digitalearth system with Direct3D?9.0c API and tested on some consumer level PC platforms.For arbitrary scene with certain LOD level,the process takes less than 10 ms,giving topologically correct,anti-aliased contour lines.展开更多
文摘城市大比例尺地形图测绘主要采用全野外数字化测量方法,效率低、劳动强度大。随着无人机倾斜摄影测量技术的飞速发展,采用该技术开展大比例尺地形图测绘成为探索和试验的热点课题。利用无人机倾斜摄影成果——数字正射影像和实景三维模型数据,采用二三维联动一体化测量软件,实现地理要素的测绘和更新。以济南市商河县老城区30 km 1∶500比例尺地形图更新为例,总结该技术应用于大比例尺地形图测绘的技术流程和技术优势。
基金supported by the National Hi-Tech Research and Development Program of China ("863" Project) (Grant Nos.2009AA12Z227,2009AA12Z215)the National Natural Science Foundation of China (Grant No.40801156)
文摘A real-time algorithm for constructing contour maps from grid DEM data is pre-sented.It runs completely within the programmable 3D visualization pipeline.The interpolation is paralleled by rasterizer units in the graphics card,and contour line extraction is paralleled by pixel shader.During each frame of the rendering,we first make an elevation gradient map out of original terrain vertex data,then figure out the final contour lines with image-space processing,and directly blend the results on the original scene to obtain a final scene with contour map using alpha-blending.We implement this method in our global 3D-digitalearth system with Direct3D?9.0c API and tested on some consumer level PC platforms.For arbitrary scene with certain LOD level,the process takes less than 10 ms,giving topologically correct,anti-aliased contour lines.
