Sometimes scientific or other specific concepts are used in areas not related to the original. This happened with the geodetic term "reference point". According to the definition, a geodetic benchmark is a mark or sign fixed at a specific point on the earth's surface. The coordinates and height of this place are calculated by leveling with respect to a known and generally accepted value.
Level Height Systems
In Russia and some countries of the former USSR, the Kronstadt footstock is considered a zero mark for counting the surface level. All the geodetic signs indicated on the maps of these countries are calculated according to the Baltic system of heights adopted in 1977. In areas of the Far East, calculations are carried out according to the Okhotsk altitude system. Its error relative to BSV is less than one meter.
A footstock is a bar with divisions for determining the level of water in a river or other body of water. Sometimes permanently installed footstocks, like reference points and reference points in geodesy, are used by scientists to observe changes in the water level in the seas, and the vertical movements of layers of the earth’s surface.
About Kronstadt footstock and sea level determination
Initially, a change in the height of the water level in the Gulf of Finland was noted by horizontal notches on the walls of canals and pools, on the surfaces of locks. When a special service was organized in Kronstadt in 1777, water was monitored at the feet of the bottom of the Obvodny Canal.
Long-term (since 1731) and regular notes, observations of fluctuations in the water levels of the Gulf of Finland were processed by the hydrograph MF Reineke in 1840. A horizontal line was carved out on the stone support of one of the bridges across the Obvodny Canal using the averaged indications he calculated. After several decades, a metal plate with a horizontal mark was fixed at this level, which practically coincided with the zero reading of the foot rod.
Land-level transfer of land
This level indicator was transferred to the mainland by leveling along the line of the St. Petersburg-Oranienbaum railway and “tied” with a mark-bolt to one of the buildings at the Baltic Station. Since 1892, this bolt has been the main benchmark for all leveling measurements in the country.
In 1946, a single system of coordinates and heights was introduced on the territory of the Soviet Union. The initial level was taken to be the Baltic Sea level with a mark corresponding to zero on the Kronstadt footstock. This is the reference point of the state leveling system. From the absolute zero mark, heights and depths are calculated for all domestic maps and locations, orbits for spacecraft flights are determined.
Varieties of benchmarks in geodesy
On the ground, the reference point is indicated by a pyramid-shaped structure made of stones, boards or metal tubes. Depending on the destination, there are several types of benchmarks:
- Centuries-old are distributed in accordance with a special scheme throughout the country. They are installed according to the instructions in the given geographical points. They are used mainly for scientific purposes.
- Fundamental are equipped along all leveling lines of the first class (between centuries) and along the most important lines of the second class. The distance between the points is from 50 to 80 km. They are laid exclusively in the ground in the form of reinforced concrete pillars and pylons. Since the fundamental reference can only be used in certain cases, an ordinary reference satellite with accurate transferred data is installed near it. It is used as a support for leveling 3 and 4 classes.
- Ordinary benchmarks are wall, rock and ground. Fixed at a distance of 3.5 to 7 km from one another, these signs can be laid along all leveling lines.
The system of interconnected fundamental and ordinary reference points forms the GHS - the state geodetic network.
Cartographic designation of geodetic signs
On maps, the reference point is marked with special icons. They are distinguished as follows:
- for astronomical points;
- for GHS items;
- for central points fixed in the territory;
- for points of filming networks;
- for points of the state leveling geodetic network.
All these points are marked on the real surface of the Earth with metal pyramids or ordinary benchmarks. Geodetic centers indicating the location of the point are plotted on the map by coordinates, that is, as accurately as possible, with indications of elevations.
What is a reference point? Elevations included in the general geodetic network, barrows, hills, or detached buildings with spiers, towers, or bells are indicated by conventionally accepted combined icons. GHS points in maps with a large scale indicate absolutely everything. Astronomical points, which are landmarks, are indicated only in cases where they are the starting points in a given area.
Triangulation (reference) points, their installation
The State Geodetic Leveling Network is engaged in the installation of permanent signs. The ground parts of the benchmarks are mutually visible to each other at a certain distance. The design and height of the signs depends on the destination, local conditions, soil and distances from one point to another.
Geodetic points can be made in the form of metal or wooden pyramids, stone or reinforced concrete pillars. The height of each structure depends on the location of the binding. Any benchmark serves as a tripod or support for the measuring tool and observer.
The underground part of this design is made in the form of a concrete monolith poured with concrete. A mark cast from metal is embedded in the point itself, which is the center of the point. The inscription on the last indicates the number and type of the item. The name of the organization that performed the work and the year of installation are cast along with the label (usually made of cast iron).
Construction and benchmarks
Disc-shaped benchmarks made by iron casting are installed in the walls of industrial buildings, locks, foundations and
supports of bridges. This is done to monitor the static state of large structures. On disc marks, in addition to inscriptions, there are protrusions intended for installation of
leveling rails. The purpose of geodetic signs can be divided into the following categories:
- supporting, or control, which are the basis for determining the position of established brands, taking into account safety and stability over time;
- auxiliary - these are intermediate characters for the transfer of coordinates and values between deformation and reference marks;
- deformation marks, which are fixed directly on the walls of the observed structures or buildings (with spatial changes in the position of the object, these marks move with it).
Reference points in construction are a guarantee of timely detection of mobility or instability of a large object, such as a hydroelectric dam or a high-rise building.
Who needs it all
Due to the interconnected system of designated points, a state geodetic network is formed. Special catalogs contain lists with the specified coordinates of all such points. These data are used by topographers to study the surface of the planet, in engineering and geodetic surveys, for various needs of the country's economy.
Lists indicating coordinate values are brought to the army officers along with topographic maps. Gunners also know well that the reference point is a mark indicating a known height, a kind of support for shooting on the ground.
Reference points on the Celsius temperature scale are considered to be the values of boiling and freezing of water at sea level.
In business, this concept is used to describe a certain state of affairs when certain actions can lead either to complete failure or to success.
Health, entrepreneurship
Since the reference point is a certain reference indicator, the “clue”, this concept can be applied in many areas of human life.
Investigating the causes of frequent stresses in people constantly living in megacities, scientists have found that the unnatural visual environment is to blame. The distribution of right angles and lines, buildings of uniform color, a large number of static objects negatively affects the emotional state of a person. The psychophysiological direction in science, called visual ecology, argues that the absence of distinctive features of architectural decorative elements overloads the optic nerve.
The eye must highlight, fix some point, detail, element in the visual space, so that the brain perceives the environment as comfortable, close to natural and harmonious. Only then does a person have a sense of aesthetic and emotional satisfaction.
Reference points in business are a kind of airbag. They can be used to increase the competitive ability of the enterprise. If you take as a basis some marketing techniques or the state of affairs in the current period, you can identify complex measures that need to be taken to change the situation for the better.