To obtain a plan of a part of the terrain, a topographic survey is performed . On the sample map below, you can see the designations of the objects, the relief, the contours of the territory. Such a document can be used to create various other schemes, plans, etc.
Mode
Topographic survey of the land can be carried out in digital or analog mode. The choice depends on how you store and provide information to the customer.
The analog mode involves the issuance of materials ( topographic plans or maps) on paper.
Digital mode is currently considered more preferable. In this case, all the information obtained during the topographic survey of the land is stored on magnetic media, disks, flash drives, etc.
Data acquisition technology
According to this criterion, the topographic survey of land is divided into:
- Ground.
- Aerial photography.
- Combined.
The first is carried out directly from the ground. Ground topographic survey of land is divided into several types depending on the technology used. She may be:
- Mensul.
- Total station.
- Vertical.
- Theodolite (horizontal).
- Phototheodolite.
Mensule shooting
When it is completed, a topographic plan is drawn on the ground. As a result, the resulting card is of high quality. However, mensul shooting involves a large amount of field work. Their implementation depends on the weather. Accordingly, labor productivity in this case is quite low. Currently, the menzul method is practically not used.
Total station survey
You can use this method regardless of weather conditions. On-site measuring information is collected. A map (plan) is compiled in office conditions (indoors).
One of the advantages of this method is the ability to automate the process of collecting and further processing the received data. This is achieved through the use of modern electronic devices.
Phototeodolite shooting
When it is carried out, photographing the area from two points of the basis is carried out. They call the distance measured with high accuracy, the ends of which are fixed on the ground by centers. Photographing is carried out with a parallel arrangement of the optical axes of the equipment.
The images obtained during the procedure make it possible to create a stereoscopic model of the area. For this, special devices are used. They can be used to obtain a topographic plan (map) based on the coordinates of the camera’s mounting points, determined by geodetic measurements, the height at which the center of the lens is located, and other external orientation parameters.
Aerial photography
It is considered the main method of state mapping of the area. Aerial photography is usually carried out in a stereotopographic manner.
The area is photographed by an aerial camera from a helicopter or plane. The task of the process is to obtain two adjacent images of the same area - stereo images. Their processing and drawing of the map is carried out on stereo devices in office conditions.
Generalized execution scheme
Specific instructions for topographic surveys are made taking into account its type and method, the instruments used, the scale of the map and other factors. Meanwhile, without going into details of this or that method, it is possible to draw up a generalized scheme for shooting. The following steps can be included in it:
- Drawing up a technical project.
- Collection of data on previously performed topographic and geodetic works on the ground.
- Choosing a shooting method.
- Creation of a core network (if it is absent on the ground).
- Shooting.
- Material processing.
- Creating a model.
- Printout of the card.
A filming network is necessary to thicken local and state networks to a certain density. Its norms depend on the type of shooting and are regulated by instructions and other industry acts.
Design
As a starting point for him is the task of conducting surveys. It is issued by the customer. The task shall indicate:
- The location of the object and its area.
- The scale of the map (plan).
- Duration of work.
In the task, significant, according to the customer, requirements for the accuracy and completeness of the image of the elements of the object can be formulated.
Shooting Selection
It depends on the area of the object, the scale of the map, the capabilities of the contractor and other factors. If, according to the results of the preliminary analysis of the object, it turns out that the survey can be performed in different ways, the cheapest is preferred.
At the end of the design phase, an estimate is made, issues of the organization of work and safety are specified.
Topographic survey of land for gasification
It is a set of works aimed at creating a map of the area for the subsequent design and construction of the gas pipeline. When conducting such a survey, certain conditions must be met:
- The map is drawn up at a scale of 1: 500. At the same time, all surface / underground communications and structures should be present on it. The map is coordinated with enterprises operating these facilities.
- The existing gas pipelines should be displayed on the plan, their characteristics are given.
- Topographic survey should be agreed with the gas company (for example, in Moscow it is Mosoblgaz). The original plan is stamped by an engineer.
- The drawings should be accompanied by a situational plan for the location of the object.
Procedure cost
The price of a topographic survey is formed from two indicators - the cost of the work itself and the payment of approval.
The cost of shooting depends on the area of the site and the surrounding area, which must be removed to create a gas pipeline project from the house to the tie-in section to the trunk.
If we take the average allotment in the Moscow region, the price of surveying will be at least 10 thousand rubles. For large customers, design companies, as well as for group orders, discounts may be provided.
Approval is paid separately, in accordance with the invoice. The customer can transfer the funds himself or entrust this to the enterprise performing the survey. In the first case, he will be able to save money, but he will lose time.
Symbols on a survey
They are special characters, with the help of which objects located on the ground are displayed on the map. The main scope of the plans: 1: 5000, 1: 2000, 1: 500 and 1: 1000. The designations, as well as the scale, are regulated by regulatory documents, including government decrees.
In accordance with GOST, the designations on the survey are divided into:
- linear
- areal;
- explanatory;
- special;
- off-scale.
Appointment
The designations provided by norms help to "read" the terrain. Based on the survey data, signs are used to create new projects.
Topographic maps differ from ordinary geographical universality. On topographic plans, not only the objective characteristics of the relief are indicated, but also the composition of the vegetation, production, industrial facilities, engineering communications, the location of the settlements.
Designation of engineering communications
They are considered mandatory. The topographic plan displays:
- telephone networks;
- Power lines;
- water and gas pipelines;
- other communications.
The naming of networks is carried out by the linear method: dashed or straight solid lines. Their thickness is different. For instance:
- Ground-based communications and pipelines are displayed with a solid straight line of 0.3 mm.
- Design, inactive, damaged ground networks are indicated with a dashed line 0.2 mm thick.
At the intersection of communications with other objects near the frame (every five centimeters), a letter characterizing the transported raw materials (product of the pipeline or network) is integrated into the line:
- The letter G indicates that gas is transported through the network. The gas pipeline can be indicated on the map by a solid line (if it is land) or intermittent (if it is underground).
- B is the water supply.
- T - heating main.
- K - sewage.
- H - oil pipeline.
Often, topographic plans indicate the pressure in the pipelines, the thickness of the pipes and the material from which they are made, the voltage in the power lines and the number of wires. At the same time, an explanatory letter of a lower case or a number is added to the first capital letter. For example, the designation "C" is a storm sewer, and "Kb" is a domestic sewer.