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QGIS Blueprints

QGIS Blueprints

By : Mearns
4.3 (3)
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QGIS Blueprints

QGIS Blueprints

4.3 (3)
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)
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8
Index

Chapter 4. Finding the Best Way to Get There

In this chapter, we will explore formal network-like geographic vector object relationships. Topological relationships are useful in many ways for geographical data management and analysis, but perhaps the most important application is optimal path finding. Specifically, you will learn how to make a few visualizations related to optimal paths: isochron polygons and accumulated traffic lines. With these visual elements as a background, we will incorporate social media feedback through Twitter in our web map application. The end result will be an application that communicates back and forth with the stakeholders about safe school routes.

In this chapter, we will cover the following topics:

  • Downloading OpenStreetMap data
  • Spatial queries
  • Installing Postgres/PostGIS/pgRouting
  • Building a topological network
  • DB Manager
  • Using the shortest path plugin to test the topology
  • Generating the costs to travel to a point for each road segment
  • Creating the isochron...
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QGIS Blueprints
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