Hydrological & Terrain Analysis using WhiteboxTools - Revision history

Smitchs: /* Downloading the DEM */

2026-01-07T19:36:20Z

Downloading the DEM

BrownWidow: /* Step 5: Finalizing TWI Visualization */

2025-12-10T01:53:26Z

Step 5: Finalizing TWI Visualization

BrownWidow: /* Step 4: Terrain Analysis */

2025-12-10T01:51:43Z

Step 4: Terrain Analysis

BrownWidow: /* Step 3: Hydrological Processing */

2025-12-10T01:43:10Z

Step 3: Hydrological Processing

BrownWidow: /* Step 2: Preprocessing */

2025-12-10T01:37:58Z

Step 2: Preprocessing

BrownWidow: /* Step 1: Importing the DEM into QGIS & Preparing Your Workspace */

2025-12-10T01:36:17Z

Step 1: Importing the DEM into QGIS & Preparing Your Workspace

BrownWidow: /* Step 0.5: Downloading the DEM */

2025-12-10T01:35:54Z

Step 0.5: Downloading the DEM

BrownWidow: /* Downloading WhiteboxTools */

2025-12-10T01:35:07Z

Downloading WhiteboxTools

BrownWidow: /* Download WhiteboxTools */

2025-12-10T01:34:47Z

Download WhiteboxTools

BrownWidow: /* Step 0: Installing WhiteboxTools */

2025-12-10T01:34:25Z

Step 0: Installing WhiteboxTools

@@ Line 54: / Line 54: @@
 X<sub>max</sub> = -115.0165557861328<br>
-Y<sub>min</sub> = 51.03926216055825<br>
+Y<sub>max</sub> = 51.03926216055825<br>
 Before submitting the request, ensure the output format is set to "GeoTiff".

@@ Line 277: / Line 277: @@
 <br clear="all"/>
-== Step 5: Finalizing TWI Visualization ==
+== '''[[Finalizing TWI Visualization]]''' ==
 Now that both layers are ready, we can stack them to create the final TWI visualization. Make sure the hillshade is below the TWI layer in the Layers panel.

@@ Line 170: / Line 170: @@
 <br clear ="all" />
-== Step 4: Terrain Analysis ==
+== '''[[Terrain Analysis]]''' ==
 === Slope ===
@@ Line 176: / Line 176: @@
 Slope is a basic tool in terrain analysis that describes how steep each cell is. It is required later for the Topographic Wetness Index (TWI), where slope influences how easily water flows downslope. Steeper slopes encourage faster runoff, while gentler slopes promote moisture retention.
-WhiteboxTools calculates slope by comparing each cell's elevation to its surrounding neighbours, providing a smooth and realistic steepness estimate across the terrain.
+WhiteboxTools calculates [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#Slope '''Slope'''] by comparing each cell's elevation to its surrounding neighbours, providing a smooth and realistic steepness estimate across the terrain.
 In the QGIS Processing Toolbox, go to: '''WhiteboxTools '''→''' Geomorphometric Tools '''→''' Slope'''.
@@ Line 199: / Line 199: @@
 === Topographic Wetness Index ===
-The Topographic Wetness Index (TWI) highlights areas where water is more likely to accumulate on the landscape. It combines upslope contributing area with slope to estimate how easily water can pool or saturate a location. Higher TWI values typically indicate wetter, more saturated zones, while lower values identify ridges or well-drained areas.
+The Topographic Wetness Index (TWI) highlights areas where water is more likely to accumulate on the landscape. It combines upslope contributing area with slope to estimate how easily water can pool or saturate a location. Higher TWI values typically indicate wetter, more saturated zones, while lower values identify ridges or well-drained areas. In WhiteboxTools, the TWI tool is called [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#WetnessIndex '''WetnessIndex'''].
 WhiteboxTools uses two inputs for this step:
@@ Line 259: / Line 259: @@
 === Optional: Adding Hillshade for Enhanced Terrain Context ===
-Hillshade is not a requirement in this workflow but placing it beneath the TWI layer with partial transparency can enhance the terrain and make the wetness patterns much easier to see. It also produces a more visually appealing final map.
+Hillshade is not a requirement in this workflow but placing it beneath the TWI layer with partial transparency can enhance the terrain and make the wetness patterns much easier to see. It also produces a more visually appealing final map. To do this, we will use the [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/geomorphometric_analysis.html#Hillshade '''Hillshade'''] tool in WhiteboxTools.
 In the QGIS Processing Toolbox, go to:

@@ Line 97: / Line 97: @@
 A quick note: WhiteboxTools also includes a '''FillDepressions''' tool. Both breaching and filling can be used for hydrological correction, but breaching tends to preserve the natural shape of the terrain better, which is helpful for mountain regions like Kananaskis.
-== Step 3: Hydrological Processing ==
+== '''[[Hydrological Processing]]''' ==
 === Flow Direction ===
@@ Line 103: / Line 103: @@
 Once the DEM is hydrologically corrected, the next step is to calculate flow direction. This tells us the direction water would flow naturally move from every cell in the DEM.
-To do this, we will use the '''D8Pointer''' tool. The D8 algorithm assigns each cell a direction based on the steepest downhill neighbour. It's simple, efficient, and is the standard method used for most hydrological workflows.
+To do this, we will use the [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/hydrological_analysis.html#D8Pointer '''D8Pointer'''] tool. The D8 algorithm assigns each cell a direction based on the steepest downhill neighbour. It's simple, efficient, and is the standard method used for most hydrological workflows.
 In the QGIS Processing Toolbox, go to: '''WhiteboxTools '''→''' Hydrological Analysis '''→''' D8Pointer'''.
@@ Line 126: / Line 126: @@
 === Flow Accumulation ===
-With flow direction calculated, the next hydrological step is to create a flow accumulation model. Flow accumulation counts how many upstream cells drain into each location, allowing us to visualize drainage density, major channels, and areas prone to runoff.
+With flow direction calculated, the next hydrological step is to create a flow accumulation model. Flow accumulation counts how many upstream cells drain into each location, allowing us to visualize drainage density, major channels, and areas prone to runoff.  To do this, we will use the [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/hydrological_analysis.html#D8FlowAccumulation '''D8FlowAccumulation'''] tool in WhiteboxTools.
 In the QGIS Processing Toolbox, go to: '''WhiteboxTools '''→''' Hydrological Analysis '''→''' D8FlowAccumulation'''.

@@ Line 75: / Line 75: @@
 Before moving on to the next step, ensure you have saved your QGIS project.
-== Step 2: Preprocessing ==
+== '''[[Preprocessing]]''' ==
 === Breaching Depressions ===
@@ Line 81: / Line 81: @@
 Before running any hydrological tools, the DEM needs to be hydrologically corrected. Raw digital elevation models almost always contain small artificial depressions that happen because of noise, interpolation gaps, or missing elevation values. These depressions trap flow, which prevents tools like D8Pointer and D8FlowAccumulation, both used in subsequent steps, from producing a proper drainage network.
-To fix this, we use '''BreachDepressions''' in WhiteboxTools, which removes the depressions by cutting narrow channels through them so water can continue flowing downslope.
+To fix this, we use [https://www.whiteboxgeo.com/manual/wbt_book/available_tools/hydrological_analysis.html#BreachDepressions '''BreachDepressions'''] in WhiteboxTools, which removes the depressions by cutting narrow channels through them so water can continue flowing downslope.
 In QGIS, open the '''Processing Toolbox'''. At the bottom of the toolbox pane, expand '''WhiteboxTools '''→''' Hydrological Analysis '''→''' BreachDepressions.'''

@@ Line 58: / Line 58: @@
 Before submitting the request, ensure the output format is set to "GeoTiff".
-== Step 1: Importing the DEM into QGIS & Preparing Your Workspace ==
+== '''[[Importing the DEM into QGIS & Preparing Your Workspace]]''' ==
 Once your DEM has been downloaded, the first step is to load it into QGIS.

@@ Line 40: / Line 40: @@
 Once configured, WhiteboxTools tools will appear in the QGIS Processing Toolbox.
-== Step 0.5: Downloading the DEM ==
+== '''[[Downloading the DEM]]''' ==
 The digital elevation model (DEM) used in this tutorial is the Copernicus GLO-30 Digital Elevation Model, downloaded through the OpenTopography portal.

@@ Line 24: / Line 24: @@
 === Downloading WhiteboxTools ===
-To download WhiteboxTools, head on over to the [https://www.whiteboxgeo.com/download-whiteboxtools/ WhiteboxTools Download Page] and download the WhiteboxTools Open Core. After downloading, extract the .zip file and place the folder somewhere easy to find. For example, you may store it in: C:\Program Files\WhiteboxTools\
+To download WhiteboxTools, head to the [https://www.whiteboxgeo.com/download-whiteboxtools/ WhiteboxTools Download Page] and download the WhiteboxTools Open Core. After downloading, extract the .zip file and place the folder somewhere easy to find. For example, you may store it in: C:\Program Files\WhiteboxTools\
 === Configuring WhiteboxTools in QGIS ===

@@ Line 23: / Line 23: @@
 == '''[[Installing WhiteboxTools]]''' ==
-=== Download WhiteboxTools ===
+=== Downloading WhiteboxTools ===
 To download WhiteboxTools, head on over to the [https://www.whiteboxgeo.com/download-whiteboxtools/ WhiteboxTools Download Page] and download the WhiteboxTools Open Core. After downloading, extract the .zip file and place the folder somewhere easy to find. For example, you may store it in: C:\Program Files\WhiteboxTools\

@@ Line 21: / Line 21: @@
 * WhiteboxTools Open Core
-== Step 0: Installing WhiteboxTools ==
+== '''[[Installing WhiteboxTools]]''' ==
 === Download WhiteboxTools ===