3D-Mesh MV

The 3D mesh is a possible representation variant of a 3D city model. It is a coherent combination of terrain surface with objects such as houses, trees, cars and is therefore also referred to as a digital surface model. The 3D mesh represents a snapshot of a realistic picture of a viewing space that can extend to entire cities, districts and federal states. For the 3D mesh, photogrammetric aerial data must be available which are recorded in aerial and laser scanning flights. The data required for a 3D mesh are point clouds and oblique aerial images. Adjacent points are connected in the triangulatation method/3D-Meshing to form three- and four-corners, which are called polygons or faces. Depending on the level of detail, the size of the individual elements of the polygons differs. The result is the polygon net, which is defined as the sum of the composition of all three- and four-corners produced. The polygon net of the three- and quadruple corners provides the basis for texturing the color information from high-resolution images. The result is the meshing of a closed, textured polygon net (grid net).三维网格（3D mesh）是三维城市模型的一种可选表示形式。它将地形表面与房屋、树木、车辆等物体进行连贯融合，因此也被称为数字表面模型。三维网格可呈现可视空间的真实场景快照，其覆盖范围可拓展至整个城市、行政区乃至联邦州。构建三维网格需依托航空飞行与激光扫描飞行采集的摄影测量航空数据（photogrammetric aerial data），所需基础数据包括点云与倾斜航空影像。通过三角剖分/三维网格构建法将相邻点连接为三角面与四边形面，此类面统称为多边形或面片。根据细节层次的不同，多边形各单元的尺寸存在差异。最终得到多边形网格，其定义为所有生成的三角面与四边形面的集合。上述由三角面与四边形面构成的多边形网格，可作为依托高分辨率影像提取色彩信息进行纹理映射的基础，最终得到闭合且已完成纹理映射的多边形网格（网格网）。