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

Managing styles


In GeoServer, we can manage style items the way we managed layers. Unlike layers, we can make styles global by not assigning them to a single workspace. This makes them usable with layers in different workspaces. On the other hand, as styles can be very specific (that is, they can use rules based on attribute data), we can also make them local by assigning them to a workspace. The styling scheme of GeoServer is very similar to QGIS and any other GIS software. We can use point, line, polygon, and raster symbolizers to describe visual properties. These symbolizers can be explained as follows:

  • Point: A symbol bound to a pair of coordinates. The symbol can be an image, or any other regular shape (for example, a square, triangle, or circle). If the symbol is a shape, it can have a stroke and a fill.
  • Line: A linear symbol described with a stroke width and a stroke color.
  • Polygon: A symbol applied to an area described by coordinate pairs in the CRS of the map. It has a stroke with...