In this way, there is only minimal distortion of the passages. The kind of error found in a loop has a big effect on how the loops can be closed. Random errors are generally small errors that occur during the process of surveying. They result from the fact that it is impossible to get absolutely perfect measurements each time you read a compass, inclinometer or tape measure. For example, your hand may shake as you read the compass, the air temperature may affect the length of the tape, and you may not aim the inclinometer precisely at the target.
Systematic errors occur when something causes a constant and consistent error throughout the survey.
The key to systematic errors is that they are constant and consistent. If you understand what has caused the systematic error, you can remove it from each shot with simple math. For example, if the compass has a five degree clockwise bias, you simply subtract five degrees from each azimuth. Blunders are fundamental errors in surveying process. Blunders are usually caused by human errors.