Book Image

Practical GIS

Book Image

Practical GIS

Overview of this book

The most commonly used GIS tools automate tasks that were historically done manually—compiling new maps by overlaying one on top of the other or physically cutting maps into pieces representing specific study areas, changing their projection, and getting meaningful results from the various layers by applying mathematical functions and operations. This book is an easy-to-follow guide to use the most matured open source GIS tools for these tasks. We’ll start by setting up the environment for the tools we use in the book. Then you will learn how to work with QGIS in order to generate useful spatial data. You will get to know the basics of queries, data management, and geoprocessing. After that, you will start to practice your knowledge on real-world examples. We will solve various types of geospatial analyses with various methods. We will start with basic GIS problems by imitating the work of an enthusiastic real estate agent, and continue with more advanced, but typical tasks by solving a decision problem. Finally, you will find out how to publish your data (and results) on the web. We will publish our data with QGIS Server and GeoServer, and create a basic web map with the API of the lightweight Leaflet web mapping library.
Table of Contents (22 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface
14
Appendix

Preparing a map


In this example, we will create our first real map, a road map of our study area. We will start by a hybrid map like the one we can see in Google Maps by changing to satellite imagery. For this task, we will need the roads layer from the OSM dataset (gis.osm_roads_free_1), the rivers layer (gis.osm_waterways_free_1), the water bodies (gis.osm_water_a_free_1), and the land-use layer (gis.osm_landuse_a_free_1). We will also need the GeoNames and the administrative boundaries layer. First of all, to speed up our work, let's extract only the relevant features. We should do the following steps to every vector layer except the administrative boundaries. If some of your layers are not that large, you can skip these steps for those layers:

  1. Add the layer from the Browser Panel, or with the Add Vector Layer tool.
  2. Open the layer's Properties window, go to the General tab, and click on the Create spatial index button.
  3. Apply a filter on the administrative boundaries layer to only show the...