Talk:Raster Analysis with GRASS tools in QGIS

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1 Introduction

This Wiki page has been created for Advanced Topics in Geographic Information Systems (GEOM4008) student at Carleton University. The main purpose of this tutorial is to introduce and familiarize future users to understand the Raster Terrain analysis with Geographic Analysis Support Analysis Support System (GRASS) tools in QGIS. A lot of scientific observations and research produces raster datasets. Raster are essentially grids of pixels that have a specific value assigned to them.

2 Objective

The objective of this tutorial would be to introduce the procedure of plugin functionalities of GRASS tools with in QGIS workspace and give some examples of Terrain Analysis modules on our area of interest (AOI) – Ottawa, Ontario.

3 Data

Certain types of raster allow you to gain more insight into the terrain that they represent. Digital Elevation Models (DEMs) are particularly useful in this regard. In this tutorial we will use DEM to find out more about our AOI.

4 Methods and Data Setup

4.1 QGIS Setup

Before beginning the tutorial install QGIS version 2.8.2, download QGIS to your computer. Please follow the steps below:

• Click this link to download.

• Choose which version is compatible with the computer you are working on Follow the steps in the pop-up downloading window

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.

• Click the QGIS icon to open the program. This will open the QGIS window.

• After the QGIS opened up add the Raster data to QGIS space

4.3 Adding Raster Layers to QGIS

• Click Add Raster layer to add the raster data.

• After the data added,

• Then right click on the data properties to project to right coordinate

• Go to Properties.

• Go to General, search or select the right coordinate system from coordinate reference system.

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.

• To add GRASS pluggin , Manage and Intall Plugins.. • Enter GRASS in the search menu to install or if the plug is already installed, it will be in the Installed selection to double click it. • After you installed, the GRASS layers will appear on the user interface.