Performing network analysis

Network analysis allows you to find the most efficient route between two points along a defined network of connected lines. These lines might represent streets, pipes in a water system, the Internet, or any number of connected systems. Network analysis abstracts this common problem so that the same techniques and algorithms can be applied across a wide variety of applications. In this recipe, we'll use a generic line network to perform analysis using the Dijkstra algorithm, which is one of the oldest algorithms used to find the shortest path. QGIS has all of this functionality built-in.

Getting ready

First, download the vector dataset from the following link, which includes two shapefiles, and unzip it to a directory named shapes in your qgis_data directory:

https://github.com/GeospatialPython/Learn/raw/master/network.zip

How to do it...

We will create a network graph by defining the beginning and end of our network of lines and then use this graph to determine...