anemometers and wind vane ars usally kept on high buildings and tower.why is that so?

Anemometer and wind vane are usually kept at high buildings and tower to provide accurate wind directions. For this they need to be high above the ground. Near the ground, obstacles such as buildings and trees cause winds be deflected or swirl around, so that it is not possible to determine the correct wind direction. Anemometer and wind vane are placed at places where no nearby taller objects can interfere with the air movement.