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

Accessing vector data


Now that you've learned the basics of raster data, let's examine vector data. This is the other fundamental data type which is used in GIS. Let's get some vector data at the top of that srtm layer. From the Browser Panel, we open up the administrative boundaries layer (the one with the shp extension) containing our study area, and the waterways and traffic layers from the OpenStreetMap data. We can also use the Add Vector Layer button from the side toolbar:

Note

If you don't see the points after opening the traffic data, you might have just opened the traffic areas layer. Geofabrik extracts distinguishable areas from lines and points by appending an a to the file name. The traffic_a_free_1.shp file contains polygons related to traffic (for example, parking lots), while the one named traffic_free_1.shp contains points. You can remove obsolete layers by right-clicking them in the Layers Panel and selecting Remove.

Now there are three vector layers with three different icons...