Stream & Catchment Delineation Using QGIS (r.watershed) скачать в хорошем качестве

Stream & Catchment Delineation Using QGIS (r.watershed)

The video demonstrates how to take raw elevation data (DEM) and transform it into meaningful geographical layers like river lines and drainage basins. Initial Setup [00:34]: The creator starts by importing a raster image (DEM) obtained from the USGS into a new QGIS project. Processing with r.watershed [01:41]: He uses the r.watershed tool from the GRASS toolbox. A key tip he provides is setting the "minimum size of exterior watershed basin" (threshold) to a value like 700 to determine the level of detail for the drainage network [02:37]. Analyzing Outputs [04:11]: The tool generates several layers, including: Drainage Direction and Slope Length. Stream Segments: Which represent the river flow [05:15]. Unique Labels: Which represent the individual sub-catchments or basins [06:15]. Vectorization [07:05]: He demonstrates how to convert these raster results into vector formats (Shapefiles). He converts stream segments into line vectors and sub-basins into polygon vectors [09:04]. Styling & Merging [11:10]: The video concludes with visual styling (changing colors for rivers and basins) and showing how to manually merge sub-catchments into one larger catchment area using the editing tools [12:42].