Final answer:
A straight line of true direction on a map is not always the shortest distance between two points on Earth.
Step-by-step explanation:
In geography, a straight line of true direction on a map is not always the shortest distance between two points on Earth. This is because maps are two-dimensional representations of the Earth's curved surface. When traveling on Earth, the shortest distance between two points is actually the arc of a great circle, which is the path that follows the curve of the Earth.
For example, if you want to fly from Chicago to Rome, a straight line on a map would not be the shortest distance. Instead, the shortest distance would be following the arc of a great circle, which takes into account the curvature of the Earth.
Therefore, when using a map, it's important to consider the scale and understand that the distances portrayed may not always be the true distances on the ground.