Identify the type of body movement holding a hand out above the ground to show the height of something

Illustrator.

Explanation:

There are three types of gestures, namely, adaptors, emblems, and illustrators.

Adaptors are gestures of touching behaviors. They indicate internal states of arousal and anxiety.

Emblems are usually agreed-on meaning gestures. For example, raising a thumb to show "OK.

Illustrator are most common type gestures. They are used to illustrate the verbal message also with the gesture.

The answer would be - illustrator.