The principles, methods and process of automated extraction of naturalstream networks of watershed based on raster DEM are described.
论述了如何基于栅格dem自动提取流域自然水系的原理、方法和流程。
2
Google has marked today's lunar eclipse with a special 'doodle' and live video stream to show the progress of the natural phenomenon.
为了纪念今天的月全食，谷歌推出了一个特别的“涂鸦”，用实时视频流展示了这一自然景观的全过程。
3
A natural pass (elevation 1, 640 feet [500 metres]) that was cut through the Cumberland Plateau in the eastern United States by former stream activity.