What are inverted sights in surveying?

Answer 1

In surveying, the term "inverted sights" refers to a method of taking measurements using a leveling instrument, such as a theodolite or a total station. It involves a specific orientation of the instrument and the sighting process.

When taking normal (direct) sights, the surveyor looks through the telescope of the instrument and aligns the crosshairs on a target or benchmark located at a higher elevation than the instrument. This is the typical method used in most surveying situations.

However, in certain situations where the target or benchmark is at a lower elevation than the instrument, the surveyor needs to use inverted sights. In such cases, the surveyor flips the telescope of the instrument upside down, and the sighting process is conducted with the instrument in this inverted position. This allows the surveyor to aim at the target or benchmark located at a lower elevation.

The use of inverted sights is necessary when surveying situations such as:

1. Taking readings across a deep valley or gorge where the target point is at a lower elevation.

2. Surveying steep slopes or cliffs where the instrument is set up at a higher elevation than the target point.

3. Conducting surveys in tunnels or other confined spaces where the target is located below the instrument.

During the use of inverted sights, the surveyor needs to take certain precautions to ensure accuracy. These precautions may include adjusting the leveling of the instrument, compensating for the inverted image, and accounting for any parallax or errors introduced by the inverted sighting process.

Inverted sights are a specialized technique used in specific surveying scenarios where the target or benchmark is at a lower elevation than the instrument. By employing this method, surveyors can accurately measure height differences and obtain reliable survey data in challenging terrain or confined spaces.

Answer 2

Inverted sight is the underside of a structure.In this the inverted sights are negative.