The system we are implementing will be called the GPS Heatmap. We will download a set of road data and convert this data into a network of directed road segments. We will then either generate or download a collection of GPS recordings from various journeys, which we will use to identify commonly-traveled roads. Finally, we will generate a heatmap based on how often the roads are traveled, providing a visual summary of the most commonly-traveled roads captured by the GPS device. The resulting output will look something like the following:
Note
A heatmap typically uses a color gradient ranging from blue to red to draw the roads, with blue used for the less-traveled roads and red for the most commonly traveled roads. In the printed edition of this book, however, the heatmaps will appear in black and white, so we have selected a single shade of blue so that the heatmap still makes sense when printed.
To allow our GPS Heatmap program to work as efficiently...