This map is not only ideal for indication geographical features, but also for direction or movement a map is handy. With direction/movement I mean for example the movement of army groups in battles, direction of rivers and sea currents and various more. For example, I would like to create a map similar to this image about a prehistoric river, notice the two arrows to indicate the direction of the flow. (This is just one example, there are various more.)
To be able to do this, we can just use a LineString, but then with indication that the start and/or end of the line should end as an arrow.