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In this exercise,您将学习如何通过使用GeneralizerTransformer in FME - this operation is commonly referred to as除草.
reducing-unnecessary-coordinates.fmwt
Note: Since you areworking on a public facing database,有时可以覆盖和/或修改表。If your translation produces unexpected results,see theResetting the PostGIS Training Database文章.或者,您可以下载提供的文件,并用适当格式的读卡器替换PostGIS读卡器。
In this scenario,您希望简化自行车路径网络以显示常规路径,而不是每个转弯。We will use the Douglas (Generalize) algorithm to reduce the density of coordinates by removing vertices,从而简化了线条。
The Generalizer transforms or measures geometry features based on a specified algorithm.有4种算法:归纳法,平滑的,Measuring,and Fitting.In this exercise,you will use a Generalizing algorithm because you want to reduce the density of coordinates by removing vertices.
Next,specify the Generalization Tolerance.泛化公差是泛化算法使用的一个参数,它与特征坐标以相同的单位进行测量。更多技术细节,see the通用文档.
You will be using the default algorithm,Douglas (Generalize) because it will remove vertices which causes a deviation of less than the Generalization Tolerance,但其余顶点的位置不变。该算法能够很好地减少一条直线上的点数;however,它不擅长保持线条相对于其他实体的形状或空间关系。
本教程中使用的数据源于City of Vancouver,不列颠哥伦比亚省。它包含根据开放政府许可证(温哥华)获得许可的信息。
?2019安全亚搏在线软件公司|合法的