The line of collimation method of reduction of levels does not provide a check on:
Options:
Explanation:
In surveying, the line of collimation method (also called the height of instrument method) is used for reducing levels. While it allows checks using the arithmetic of levels for back sights (BS) and fore sights (FS), it does not provide a direct check on intermediate sights (IS). This is because intermediate sights are only used to calculate reduced levels and do not contribute to the balancing of level differences.
Answer:
The line of collimation method of reduction of levels does not provide a check on: Intermediate sights.