Annotated Driving Directions

In order to complete MeeshQuest functionality we will be adding the ability to print out annotated driving directions. For driving directions to be useful, people often need the distinction of GO STRAIGHT, TURN RIGHT or TURN LEFT. In Part 2 we introduce a new command which adds these labels to its output.

In order to determine which "direction" someone should go, we will define a simple set of rules based on the angle formed by the road you are on and the road you need to "turn" onto.

On the chart below, line (A,B) represents the road that you are on, or the current road. Line BC represents the next road you want to take on your route. From the chart you will notice that road (B,C) falls within the GO STRAIGHT section of the circle. If we drew a line from points B to D then the next road would fall in the TURN RIGHT section of the circle.