Book Image

Hands-On Geospatial Analysis with R and QGIS

By : Shammunul Islam, Brad Hamson
Book Image

Hands-On Geospatial Analysis with R and QGIS

By: Shammunul Islam, Brad Hamson

Overview of this book

Managing spatial data has always been challenging and it's getting more complex as the size of data increases. Spatial data is actually big data and you need different tools and techniques to work your way around to model and create different workflows. R and QGIS have powerful features that can make this job easier. This book is your companion for applying machine learning algorithms on GIS and remote sensing data. You’ll start by gaining an understanding of the nature of spatial data and installing R and QGIS. Then, you’ll learn how to use different R packages to import, export, and visualize data, before doing the same in QGIS. Screenshots are included to ease your understanding. Moving on, you’ll learn about different aspects of managing and analyzing spatial data, before diving into advanced topics. You’ll create powerful data visualizations using ggplot2, ggmap, raster, and other packages of R. You’ll learn how to use QGIS 3.2.2 to visualize and manage (create, edit, and format) spatial data. Different types of spatial analysis are also covered using R. Finally, you’ll work with landslide data from Bangladesh to create a landslide susceptibility map using different machine learning algorithms. By reading this book, you’ll transition from being a beginner to an intermediate user of GIS and remote sensing data in no time.
Table of Contents (12 chapters)
GRASS, Graphical Modelers, and Web Mapping

Digitizing a map

In this section, we'll learn how to digitize a map, which will allow us to work with this map for further spatial analysis. In doing so, we need to know the coordinates of some of the point locations on this image. We'll use these location coordinates to digitally get coordinates of all points on the image. These points are called Ground Control Points (GCPs).

Now we'll digitize an image of a district of Bangladesh, Gazipur, using GCPs:

  1. Click on Manage and Install Plugins under Plugins.
  2. Now we see the Plugins window. We need to write Georeferencer GDAL in the Search bar, click on Georeferencer GDAL, and then click on Close, as shown in the following screenshot:
  1. We need to open the Georeferencer window by clicking on Georeferencer under Raster from the menu bar, which again shows Georeferencer, which we need to click again.
  2. A new window for...