What Is Linear Measurement Surveying | Types of Linear Measurement Surveying
Introduction of Measuring Distance
Distance measurement is usually regarded as the most fundamental of surveying observations. In traditional ground surveys, although many angles might be read, the length of at least one line has to be measured to supplement the angles in locating points.
In-plane surveying, the distance between two points means the horizontal distance. When the points are at different elevations, the distance is the horizontal length between vertical lines in the points.
Lengths of lines could be specified in different units. In the USA, the foot, decimally divided, is usually used through the meter is becoming more and more common. Geodetic surveys and lots of highway surveys use the meter.
In machine and architectural function, and on some construction projects, the unit is a foot divided into inches and fractions of an inch.
In surveying, the most commonly employed units are such as length, area, volume, and angle.
Two different systems are in use for specifying units of observed quantities, both the English and metric systems.
Due to its widespread adoption, the metric system is called the International System of Units and abbreviated SI
Traversing over great distances, with much greater control of swing errors.
The inclusion of the many more measured distances into control networks, rendering classical triangulation outdated. This results in a much greater control scale error.
Setting-out and photogrammetric control, over the large areas, by polar coordinates from a single baseline.
Deformation monitoring into sub-millimeter accuracies using high-precision EDM, such as the Mekometer ME5000.
This instrument has a range of 8 km, and an accuracy of ±0.2 mm ±0.2 mm/km of the distance measured ignoring unmodelled refraction effects.
Instrumental Errors: These errors occur due to imperfections or malfunctions in the surveying instruments used for measuring distances, such as theodolites, total stations, or EDM (Electronic Distance Measurement) devices. Instrumental errors can result from issues like misalignment, incorrect calibration, faulty components, or inadequate maintenance of the equipment.
Environmental Factors: Environmental conditions can affect the accuracy of linear measurements. Factors like temperature, humidity, atmospheric pressure, and wind can introduce errors, especially in instruments that are sensitive to these parameters. For example, temperature variations can cause expansion or contraction of measurement tapes or EDM equipment, leading to inaccuracies.
Refraction: Refraction is the bending of light rays as they pass through different media, such as the Earth's atmosphere. When surveying over long distances, particularly over water bodies or uneven terrain, refraction can cause errors in linear measurements. This effect is more significant for optical instruments like theodolites and less pronounced