Terrain Analysis with GRASS tools in QGIS - Revision history

GrahamScott: /* Conclusion */

2022-09-30T18:48:17Z

Conclusion

GrahamScott: /* Sources of Error */

2022-09-30T18:43:54Z

Sources of Error

GrahamScott: /* 4 Methods and Data Setup */

2022-09-30T18:40:05Z

4 Methods and Data Setup

GrahamScott: /* 4 Methods and Data Setup */

2022-09-30T18:27:26Z

4 Methods and Data Setup

GrahamScott: /* 3 Data */

2022-09-30T18:26:08Z

3 Data

GrahamScott: /* 2 Objective */

2022-09-30T18:25:48Z

2 Objective

GrahamScott: /* 1 Introduction */

2022-09-30T18:25:25Z

1 Introduction

Smitch: Fixed several small grammar errors and typos, removed a misleading statement about CRS, and fixed a mistaken statement about GRASS database locations.

2017-11-28T17:06:15Z

Fixed several small grammar errors and typos, removed a misleading statement about CRS, and fixed a mistaken statement about GRASS database locations.

Kirkhenike at 01:56, 20 October 2017

2017-10-20T01:56:31Z

Show changes

Kirkhenike at 17:30, 18 October 2017

2017-10-18T17:30:19Z

@@ Line 157: / Line 157: @@
 == Conclusion ==
-We have successfully demonstrated how to use various Terrain Analysis tools offered in the free and open source software of GRASS within QGIS using a DEM of the Gatineau Park region. The Raster Terrain Analysis Plugin can be used to calculate the slope, aspect, hill shade, ruggedness index and relief for digital elevation models (DEM). It is very simple to handle and provides an intuitive graphical user interface for creating new raster layers. This workflow is a preliminary understanding of the basic functions available with GRASS plugins, different types of manipulations as mentioned can be conducted easily under this platform. Many different sources of literature can be found online to provide more theoretical understanding into the processing methods and how to curtail the analysis process to develop different data sets as well as work around's. Below one can find some links to literature, they discuss various DEM processing and application methods. Additional "How To" links for Youtube videos have been linked for an in action use of the GRASS programs and plugins.
+In this tutorial, learning how to use various Terrain Analysis Tools in the free and open source software of QGIS using the GRASS Plugin has been successfully demonstrated. The Raster Terrain Analysis Plugin can be used to calculate the slope, aspect, hill shade, ruggedness index and relief for digital elevation models. It is very simple to handle and provides an intuitive graphical user interface for creating new raster layers. This workflow is a preliminary understanding of the basic functions available with GRASS plugins, different types of manipulations as mentioned can be conducted easily under this platform. Many different sources of literature can be found online to provide more theoretical understanding into the processing methods and how to curtail the analysis process to develop different data sets as well as work around's. Below one can find some links to literature, they discuss various DEM processing and application methods. Additional "How To" links for Youtube videos have been linked for an in action use of the GRASS programs and plugins.
 == Reference ==

@@ Line 151: / Line 151: @@
 == Sources of Error ==
-• Many of the sources of error are user or administration based, what is meant by this, understanding ones own nomenclature. Though this seams simple in this example, as more renderings are produced of the same area with different levels of scale, changing the resolution between each scale set and ensuring the analysis produced is not biased in any way. Bias' may include incorrect matching of DEM and Raster resolutions, a difference in projections and so on.
+• Many of the sources of error are user or administration based. This means understanding ones own nomenclature. Though this seams simple in this example, as more renderings are produced of the same area with different levels of scale, changing the resolution between each scale set and ensuring the analysis produced is not biased in any way. Bias' may include incorrect matching of DEM and Raster resolutions, a difference in projections, and so on.
 • Know that many other sources of error do exist, those mentioned above only included user error and not error in the original data. This workflow assumes the original data is accurate before any analysis is conducted.
 == Conclusion ==

@@ Line 32: / Line 32: @@
 • Once you have completed the installation of QGIS and found all the data you want to use, create a folder on your computer and place the data in your created folder.
-• Click the QGIS icon to open the program.[[File:qgis.jpeg]] This will open the QGIS application.
+• Click the QGIS icon to open the program. This will open the QGIS application. [[File:QGIS Application.jpg|50px]]
 • After QGIS opens up, add the Raster data to QGIS space as detailed below...
@@ Line 41: / Line 41: @@
 • Find the layer option in the header, click ‘add layer’ and then click’ add raster layer’. Add the Raster layer to the data set.
-[[File:raster.jpeg]]
+[[File:Raster Option.jpg|350px]]
 • Once your data has been added, right click on the data, select properties, and then select source. Set the projection to the proper projection and coordinate system for your location:
-[[File:source.jpeg]]
+[[File:Source.jpg|350px]]
@@ Line 58: / Line 58: @@
 • After it is installed, the GRASS toolbar layer will appear on the user interface.
-[[File:grass.jpeg]]
+[[File:Grass plugin.jpg|350px]]
 '''4.5 Creating GRASS Database'''
@@ Line 68: / Line 68: @@
 • In the new map set browse to your existing directory or create a new one and then click next.
-[[File:nhm17.jpg|300]]
+[[File:nhm17.jpg|400px]]
 • To create the GRASS location, click on create new location and name it appropriately and click next.
@@ Line 82: / Line 82: @@
 •  Finally create the GRASS new mapset by giving it appropriate name. Name the mapset appropriately.
-[[File:nhm21.jpg|350]]
+[[File:nhm21.jpg|350px]]
 == Data Processing  ==

@@ Line 17: / Line 17: @@
 ''' 4.1 QGIS Setup'''
-Before beginning the tutorial install QGIS version 2.8.2; first, download QGIS to your computer.
+Before beginning the tutorial, you must install QGIS version 3.22.2; first, download QGIS to your computer.
 Please follow the steps below:
-• [http://qgis.org/en/site/forusers/download.html Click this link to download].
+• [http://qgis.org/en/site/forusers/download.html Click this link to download QGIS to your personal computer].
-• Choose which version is compatible with the computer you are working on.  Follow the steps in the pop-up downloading window.
+• Choose which version is compatible with the computer you are working on. For me, this is version 3.22.2. Follow the steps in the pop-up downloading window. But note, the latest version is preferred for this tutorial.
-• Know there are many sources that can provide QGIS work space software packages. For this tutorial, the link and the steps below are specific to this source and the available versions of QGIS.
+• There are many sources that can provide QGIS workspace software packages. For this tutorial, the link and the steps below are specific to this source and the available versions of QGIS.
 '''4.2 Opening QGIS'''
-• Once you completed the installation and found all the data you want to use, create a folder in your computer and place the data in this folder.
+• Once you have completed the installation of QGIS and found all the data you want to use, create a folder on your computer and place the data in your created folder.
-• Click the QGIS icon to open the program.[[File:qgis.jpg]] This will open the QGIS window.
+• Click the QGIS icon to open the program.[[File:qgis.jpeg]] This will open the QGIS application.
-• After the QGIS opens up, add the Raster data to QGIS space as detailed below...
+• After QGIS opens up, add the Raster data to QGIS space as detailed below...
 '''4.3 Adding Raster Layers to QGIS'''
-• Find and click  [[File:addraster.jpg]]  Add the Raster layer to the data set.
+• Find the layer option in the header, click ‘add layer’ and then click’ add raster layer’. Add the Raster layer to the data set.
+[[File:raster.jpeg]]
-• Once the data have been added, right click on the data properties to set the projection to the proper projection and coordinate system:
+• Once your data has been added, right click on the data, select properties, and then select source. Set the projection to the proper projection and coordinate system for your location:
-• Go to Properties.[[File:properties.jpg]]
+[[File:source.jpeg]]
-• Go to General, search or select the right coordinate system from coordinate reference system. The projection displayed "NAD83/UTM zone 18N" is specific for data that are to be analysed.
-[[File:general.jpg|300]]
 '''4.4 Installing and Setting up the GRASS Plugin'''
-After the initial QGIS window has been opened and data added, next the GRASS Plugin be installed. The GRASS Plugin allows the tools from GRASS to be used within QGIS.
+After the initial QGIS window has been opened and data has been added, next the GRASS Plugin. The GRASS Plugin allows the tools from GRASS to be used within QGIS.
-• To add GRASS plugin , find Plugins in the menue bar, then Manage and Install Plugins in the drop down menue
+• To add the GRASS plugin, select Plugins in the menu bar, then select Manage and Install Plugins in the drop-down menu.
+•  Search for GRASS in the search bar to install or if the plugin is already installed, it will be an option under the Installed column, select it here.
-[[File:pluginnn.jpg]]                                                                                                                                                                                                                         [[File:grassnhm2.jpg|300px|thumb|right]]
-•  Enter GRASS in the search menu to install or if the plugin is already installed, it will be an option under the Installed column, select it here.
 • After it is installed, the GRASS toolbar layer will appear on the user interface.
-[[File:grasstools.jpg|300px|]]
+[[File:grass.jpeg]]
-'''4.5  Creating GRASS Database'''
+'''4.5 Creating GRASS Database'''
 • A GRASS Database is require to use these processes. Similar as a work space in ArcMap, except that a GRASS database MUST be stored all within a designated save location. To create the GRASS database, click on the New Map Set boxed in red.

@@ Line 12: / Line 12: @@
 == 3 Data ==
-The type of raster data that is to be used is referred to as DEM or Digital Elevation Model, it contains information that is specific to determining things like Aspect and Slope. Slope and Aspect are important as they refer to the degree of pitch, the length of the pitch and the direction of the pitch. The combination of these two data inputs will create the model by witch we can analyze various depressions and flow pathways in the AOI (Area of Interest) or Gatineau Park.
+The type of raster data that we will be using is referred to as DEM or Digital Elevation Model. It contains information that is specific to determining things like Aspect and Slope. Slope and Aspect are important as they refer to the degree, length, and direction of the pitch. The combination of these two data inputs will create the model by which we can analyze various depressions and flow pathways in the AOI or Gatineau Park.
 == 4 Methods and Data Setup ==

@@ Line 8: / Line 8: @@
 == 2 Objective ==
-The purpose of this tutorial is to touch on the concept of terrain based analysis using raster data. It will also include a work flow with detailed information into each step as to why the specified steps are important. Other general concepts and functionalities are also to be found with quick tips and tricks. Due to the specificity of GRASS tools and the QGIS workspace many steps will have to be repeated to ensure proper procedures and develop the appropriate data. The Area Of Interest (AOI) includes Gatineau Park, this analysis details the steps to create an elevation and depression model based on various resolutions. One can find supporting literature and videos linked in the Reference section.
+The purpose of this tutorial is to touch on the concept of terrain-based analysis using raster data. It will also include a plan with detailed information into each step as to why the identified steps and processes are important. Other general concepts and functionalities are also to be found with quick tips and tricks. Due to the specificity of GRASS tools and the QGIS workspace many steps will have to be repeated to ensure proper procedures and develop the appropriate data. The Area of Interest (AOI) for this tutorial is Gatineau Park, and the analysis details in the steps create an elevation and depression model based on various resolutions. One can find supporting literature and videos linked in the Reference section.
 == 3 Data ==

← Older revision		Revision as of 18:25, 30 September 2022
Line 4:		Line 4:


	This Wiki page was created for Advanced Topics in Geographic Information Systems (~~GEOM4008~~) students at Carleton University. The main purpose of this tutorial is to introduce and familiarize future users to understand the Raster Terrain analysis within Geographic Analysis and Support Systems (GRASS) tools in QGIS. Many familiar topics will touched upon, know that a basic understanding of geomatics or similar fields of study are needed as the complexity and the terminology are subjective based on geomatics and data processing techniques.		This Wiki page was created for Advanced Topics in Geographic Information Systems (GEOM 4008) students at Carleton University. The main purpose of this tutorial is to introduce and familiarize future users to understand the Raster Terrain analysis within Geographic Analysis and Support Systems (GRASS) tools in QGIS. Many familiar topics will be touched upon, know that a basic understanding of geomatics or similar fields of study are needed as the complexity and the terminology are subjective based on geomatics and data processing techniques.


	== 2 Objective ==		== 2 Objective ==

@@ Line 4: / Line 4: @@
-This Wiki page was created for Advanced Topics in Geographic Information Systems (GEOM4008) students at Carleton University. The main purpose of this tutorial is to introduce and familiarize future users to understand the Raster Terrain analysis within Geographic Analysis and Support Systems (GRASS) tools in QGIS. Many familiar topics will touched upon, know that a basic understanding of geomatics or similar fields of study are needed as the complexity and the terminology are subjective based on geomatics and data processing like techniques.
+This Wiki page was created for Advanced Topics in Geographic Information Systems (GEOM4008) students at Carleton University. The main purpose of this tutorial is to introduce and familiarize future users to understand the Raster Terrain analysis within Geographic Analysis and Support Systems (GRASS) tools in QGIS. Many familiar topics will touched upon, know that a basic understanding of geomatics or similar fields of study are needed as the complexity and the terminology are subjective based on geomatics and data processing techniques.
@@ Line 42: / Line 42: @@
 • Find and click  [[File:addraster.jpg]]  Add the Raster layer to the data set.
-• Once the data has been added, right click on the data properties to set the projection to the proper projection and coordinate system:
+• Once the data have been added, right click on the data properties to set the projection to the proper projection and coordinate system:
 • Go to Properties.[[File:properties.jpg]]
-• Go to General, search or select the right coordinate system from coordinate reference system. The projection displayed "NAD83/UTM zone 18N" is specific for data that is to be analysised. Other suitable projections for this application include "Lambert Conformal Conic" and "WGS 1984".
+• Go to General, search or select the right coordinate system from coordinate reference system. The projection displayed "NAD83/UTM zone 18N" is specific for data that are to be analysed.
 [[File:general.jpg|300]]
@@ Line 54: / Line 54: @@
 After the initial QGIS window has been opened and data added, next the GRASS Plugin be installed. The GRASS Plugin allows the tools from GRASS to be used within QGIS.
-• To add GRASS pluggin , find Plugins in the menue bar, then Manage and Install Plugins in the drop down menue
+• To add GRASS plugin , find Plugins in the menue bar, then Manage and Install Plugins in the drop down menue
 [[File:pluginnn.jpg]]                                                                                                                                                                                                                         [[File:grassnhm2.jpg|300px|thumb|right]]
@@ Line 67: / Line 67: @@
 '''4.5  Creating GRASS Database'''
-• A GRASS Database is require to use these processes. Similar as a work space in ArcMap, the same should be done, however a designated save location is much more user friendly if one plans to use this software on more than one occasion. To create the GRASS database, click on the New Map Set boxed in red.
+• A GRASS Database is require to use these processes. Similar as a work space in ArcMap, except that a GRASS database MUST be stored all within a designated save location. To create the GRASS database, click on the New Map Set boxed in red.
 [[File:nhm16.jpg|400px]]

@@ Line 162: / Line 162: @@
 == Conclusion ==
-We have successfully demonstrated how to use various Terrain analysis tools offered in the free and open source software of GRASS with in QGIS using a DEM of the Ottawa region. The Raster Terrain Analysis Plugin can be used to calculate the slope, aspect, hillshade, ruggedness index and relief for digital elevation models (DEM). It is very simple to handle and provides an intuitive graphical user interface for creating new raster layers.
+We have successfully demonstrated how to use various terrain analysis tools offered in the free and open source software of GRASS with in QGIS using a DEM of the Ottawa region. The Raster Terrain Analysis Plugin can be used to calculate the slope, aspect, hill shade, ruggedness index and relief for digital elevation models (DEM). It is very simple to handle and provides an intuitive graphical user interface for creating new raster layers. This workflow is a preliminary understanding of the basic functions available with GRASS plugins, different types of manipulations as mentioned can be conducted easily under this platform. Many different sources of literature can be found online to provide more theoretical understanding into the processing methods and how to curtail the analysis process to develop different data sets as well as work around's. Below one can find some links to literature, they discuss various DEM processing and application methods. additional how to links for Youtube videos have been linked for an in action use of the GRASS programs and plugins.
 == Reference ==
@@ Line 169: / Line 169: @@
 GRASS GIS Integration: https://docs.qgis.org/2.8/en/docs/user_manual/grass_integration/grass_integration.html. [Web] accessed: Dec 22, 2015.
 QGIS Application : http://hub.qgis.org/projects/quantumgis/wiki/Adding_New_Tools_to_the_GRASS_Toolbox. [Web] accessed: Dec 22, 2015.
+DEM Raster Resolution and Order Sequencing : http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9671.2004.00169.x/epdf. [Web] accessed Oct 18, 2017.
+Watershed Basin Analysis Using GRASS : https://www.youtube.com/watch?v=6BQltTwsU7A. [Web] accessed Oct 18, 2017.