Book Image

QGIS Blueprints

By : Mearns
Book Image

QGIS Blueprints

By: Mearns

Overview of this book

QGIS, the world’s most popular free/open source desktop geographic information system software, enables a wide variety of use cases involving location – previously only available through expensive specialized commercial software. However, designing and executing a multi-tiered project from scratch on this complex ecosystem remains a significant challenge. This book starts with a primer on QGIS and closely related data, software, and systems. We’ll guide you through six use-case blueprints for geographic web applications. Each blueprint boils down a complex workflow into steps you can follow to reduce time lost to trial and error. By the end of this book readers should be able to build complex layered applications that visualize multiple data sets, employing different types of visualization, and give end users the ability to interact with and manipulate this data for the purpose of analysis.
Table of Contents (9 chapters)
8
Index

Chapter 1. Exploring Places – from Concept to Interface

How do we turn our idea into a location-based web application? If you've heard this question before or asked it yourself, you would know that this deceptively simple question can have answers posed in a limitless number of ways. In this book, we will consider the application of QGIS through specific use cases selected for their general applicability. There's a good chance that the blueprint given here will shed some light on this question and its solution for your application.

In this book, you will learn how to leverage this ecosystem, let the existing software do the heavy lifting, and build the web mapping application that serves your needs. When integrated software is seamlessly available in QGIS, it's great! When it isn't, we'll look at how to pull it in.

In this chapter, we will look at how data can be acquired from a variety of sources and formats and visualized through QGIS. We will focus on the creation of the part of our application that is relatively static: the basemap. We will use the data focused on a US city, Newark, Delaware. A collection of data, such as historical temperature by area, point data by address, and historical map images, could be used for a digital humanities project, for example, if one wanted to look at the historical evidence for lower temperatures observed in a certain part of a city.

In this chapter, we will cover the following topics:

  • The software
  • Extract, Transfer, and Load
  • Georeference
  • The table join
  • Geocoding
  • Orthorectification
  • The spatial reference manipulation
  • The spatial reference assignment
  • Projection
  • Transformation
  • The basemap creation and configuration
  • Layer scale dependency
  • Labeling
  • The tile creation