# Slope Profiles Part 2: Measuring Slope Angles

The basic principle of slope angle measurements, which applies to the use of protractors, clinometers and total stations.

### Basic principle ↑

There are several ways to calculate slope angle. Common measuring equipment such as clinometers and total stations both use a similar method of raising the geometry of the slope below. By placing poles of equal heights at Points A and B, the line from the top of Pole A to Pole B is parallel to the actual slope. The line has the same angle as the slope below. The “easiest” way (which is not the same as the most accurate way) to measure this angle would be to place a protractor on the top of Pole A, drag a string from the top of Pole A to Pole B and read the angle. Note: This method would only be accurate if your protractor is perfectly flat at 180°. ### Clinometers ↑

Clinometers are essentially protractors that are a little bit more sophisticated. Clinometers provide more accurate measurements because their design helps the surveyor correct for holding error (i.e. ensuring that the base of the “protractor” component is perfectly horizontal). A clinometer Some compasses have clinometers built into them. … you can also make one of your own with a protractor, straw, and a weighted string (if you make one as shown in the picture, you’d have to subtract the angle from 90 degrees. Can you figure out why?).

### Total stations ↑

Total stations also use the same principle to calculate slope angle. The total station would be positioned at Point A, and the total pole would be positioned at Point B. 