Which term refers to angles measured east or west from a North-South line?

The term that refers to angles measured east or west from a North-South line is known as bearing angles. In surveying, a bearing angle is typically expressed in terms of the angle measured from either the North or South direction, going around clockwise or counterclockwise to indicate whether the angle is towards the east or west. This is an essential concept in navigation and land surveying, as it helps in pinpointing exact locations and directions relative to cardinal points.

For example, a bearing might be noted as N30°E, indicating that the angle is measured 30 degrees east from due north. This method is practical for accurately describing the orientation of lines or boundaries on the earth's surface. In contrast, azimuth angles are measured clockwise from the North and are usually expressed in degrees from 0° to 360°, while vertical angles are measured in the vertical plane in relation to horizontal and are not typically concerned with east-west measurements. Horizontal angles are measured in a horizontal plane but do not specifically denote a north-south reference for east-west orientation.