Angle of elevation and depression
Here is a picture
https://www.mathsisfun.com/definitions/angle-of-elevation.html
If you have a device that measures angle above or below level (a bubble sextant does or a transit as used by surveyors) you can figure out how far something is above or below you.
For example if you are standing on the ground and looking at the top of a building 100 meters away and you device says the angle between horizontal and the top is 30 degrees that means the angle of elevation is 30 degrees.
That means that the tangent of 30 degrees = height of building above your eye / 100 meters horizontal to building from you
depression angle is the same thing but BELOW horizontal
The concepts of angle of elevation and angle of depression are used in trigonometry and geometry to describe the angle between a horizontal line and a line of sight from an observer to an object.
Angle of Elevation:
The angle of elevation is the angle between the horizontal line of sight and the upward direction from the observer to the object. It is usually measured above the horizontal line. This angle is used when the object being observed is located at a higher level than the observer.
To find the angle of elevation, you typically need two measurements: the height of the object and the horizontal distance from the observer to the object. Once you have this information, you can use the trigonometric tangent function (tan) to calculate the angle of elevation.
Here's how to find the angle of elevation:
1. Determine the vertical height (h) of the object above the observer.
2. Measure the horizontal distance (d) between the observer and the object.
3. Use the formula: angle of elevation = arctan(h/d).
arctan refers to the inverse tangent function.
Angle of Depression:
The angle of depression, on the other hand, is the angle between the horizontal line of sight and the downward direction from the observer to the object. It is usually measured below the horizontal line. This angle is used when the object being observed is located at a lower level than the observer.
To find the angle of depression, you also need two measurements: the depth of the object below the observer and the horizontal distance from the observer to the object. By using the same trigonometric tangent function (tan), you can calculate the angle of depression.
Here's how to find the angle of depression:
1. Determine the vertical depth (d) of the object below the observer.
2. Measure the horizontal distance (h) between the observer and the object.
3. Use the formula: angle of depression = arctan(d/h).
arctan refers to the inverse tangent function.
Remember, when using trigonometric functions to find angles, always make sure your calculator is set to the correct angle mode (degrees or radians) that matches the measurements you are working with.