Posted on February 14, 2023 (Updated on July 10, 2025)

Error when using r.watershed in QGIS 2.10.1 with Grass

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What is the difference between Qgis and Qgis with grass?

GRASS has full/real topology support, that means that a single boundary can share several areas . QGIS is primarily non-topological or “spaghetti” , adjacent area boundaries are duplicated. And they relate in the way that Qgis can display and edit GRASS vectors through the GRASS plugin, preserving the topology.
 

What is R watershed?

r. watershed offers two methods to calculate surface flow: single flow direction (SFD, D8) and multiple flow direction (MFD). With MFD, water flow is distributed to all neighbouring cells with lower elevation, using slope towards neighbouring cells as a weighing factor for proportional distribution.

How do you delineate a drainage basin in Qgis?

How to Delineate a Watershed in 8 Steps

  1. Find DEM data.
  2. Fill Sinks.
  3. Generate the Stream Network.
  4. Generate a Polyline of the Stream Network.
  5. Project Outlet Point.
  6. Extract Coordinates of Outlet Point.
  7. Generate Watershed of the Stream Network.
  8. Raster to Vector.

 

How do I get GRASS to work in QGIS?

Right click on the new mapset and select Open Mapset to activate GRASS Tools. GRASS Tools will open in a panel on the right. The best practice for working with GRASS GIS is to use the PERMANENT mapset for reference data and use other mapsets for new data that you create.

How do I enable GRASS in QGIS?

To launch GRASS from within QGIS, you need to activate it as with any other plugin:

  1. First, open a new QGIS project.
  2. In the Plugin Manager, enable GRASS in the list: The GRASS toolbar and the GRASS panel will appear: Fig. 12.10 GRASS toolbar. Fig. 12.11 GRASS Panel.


Which plugin do you use in Qgis for watershed delineation?

Plug-ins installation



First go to the main tool bar at the top, click on Plugins then Manage and Install Plugins… And to help us with 3D modeling, we will install the plug-in Qgis2threejs, which will use the elevation values in our DEM to create a 3D model of our catchment area.
 

What are the three types of watershed?

Watersheds are classified depending upon the size, drainage, shape and land use pattern.

  • Macro watershed (> 50,000 Hect)
  • Sub-watershed (10,000 to 50,000 Hect)
  • Milli-watershed (1000 to10000 Hect)
  • Micro watershed (100 to 1000 Hect)
  • Mini watershed (1-100 Hect)


What are the 3 main functions of a watershed?

WATERSHED FUNCTIONS



There are three processes within a watershed that can protect water quality if pre- served: water capture, water storage, and water release.

What is the use of GRASS in QGIS?

The GRASS plugin in QGIS is designed for users who are new to GRASS and not familiar with all the modules and options. As such, some modules in the Toolbox do not show all the options available, and some modules do not appear at all.

Is GRASS included in QGIS?

12.1.1.



To launch GRASS from within QGIS, you need to activate it as with any other plugin. First, open a new QGIS project. Before you can use GRASS, you need to create a mapset. GRASS always works in a database environment, which means that you need to import all the data you want to use into a GRASS database.

Which version of QGIS should I use?

The 64bit version is recommended for almost all users, unless you are attempting to install the software on a extremely old computer that has a 32 bit processor. It is also recommended that you install the latest release rather than the long term release so that you have access to the latest QGIS features.