QGIS 101: Extract the Streams - Mapping catchments & streams from DEM - Part 3 of 3

Video 3 of 3, Mapping catchments and streams from DEM. In this video we will extract the streams from the Salma dam catchment in Afghanistan using the filled DEM we prepared in the first video, and the flow accumulation and flow direction grids we prepared in the second video.
If we want to understand the water balance of a catchment or drainage basin, we need to start by delineating the catchment/watershed. In this three-part sequence we will prepare the DEM (Video 1), map the catchment/watershed (Video 2) and extract the streams (Video 3).

00:00 Introduction
00:22 Step 7: Extract the streams
02:31 Select streams using the Raster Calculator
03:12 Select streams using Accumulation Grid Symbology
04:45 GRASS - Raster - r.stream.extract
06:46 No vector layer created? What to do...
07:22 Select streams inside catchment
08:28 Export streams
08:53 Formatting streams & catchment
09:29 Hide DEM outside the catchment using inverted polygon
10:45 Final words

Link to Video 1:    • QGIS 101: Prepare the DEM - Mapping catchm...  
Link to Video 2:    • QGIS 101: Map the Catchment - Mapping catc...  
Link to Video 3:    • QGIS 101: Extract the Streams - Mapping ca...   (THIS VIDEO)

This video is part of the online QGIS 101 training course.
For more QGIS videos see the QGIS playlist:    • QGIS 101  

#QGIS #Streams #Catchment