The most common procedure in engineering geodesy is considered to build a theodolite move - system of broken lines and measured between the angles between them. It is called it, if it relies only on one source point, and its parties form a polygonal figure. Consider in more detail how the theodolite stroke of a closed type is created and what features he has.
Persons can form entire networks in crossing each other and covering significant areas, and their form is determined by the peculiarities of the area. They are accepted for:
- closed (polygon);
- open;
- suspension;
- Diagonal (paired inside other moves). If it is necessary to fall asleep at a flat section, such as a construction site, the best choice will be a landfill. At the facilities of an elongated type, like roads, it is customary to use an open course, and suspension - to shoot a closed area, like deaf streets.
A closed course in its essence is a polygonal figure and relies only on one base point with installed coordinates and a directing angle. The peaks of the side protrude dots fixed on the ground, and segments - the distance between them. It is most often created for shooting construction sites, residential buildings, industrial structures or land plots.
Procedure for performing work
Like other geodesic measures, this procedure is carried out with preliminary preparation to obtain accurate metric data. An important role is also played by their mathematical processing. The work themselves are carried out on the principle of common to private and consist of the following steps:
- Recognitive area. Evaluation of the removable territory, studying its features. At this stage, the location of the removable points is determined.
- Field shooting. Works are directly on the ground. Performing linear and angular measurements, drawing up abrasions, preliminary calculations and changes when necessary.
- Cameral processing. The final stage of the work, which consists in calculating the coordinates of the closed theodolite stroke and the subsequent preparation of the plan and the technical reference.
Recognition and field measurements are performed directly at the facility and are the most time-consuming and cost-effective activities. However, further result depends on the quality of them.
Data processing is carried out already indoors. Today it is carried out with the help of special software, although manual calculations are all also relevant and can be used by a survey for verification purposes.
Data processing
Processing the results of measurements of a closed theodolite stroke will allow you to evaluate the quality of the work done and make corrections to the obtained geometric values. To ensure that the angular and linear dimensions are in admission, and during field work, primary calculations are performed.
To calculate the values \u200b\u200bof the coordinates of the points of the closed stroke use such data:
- coordinates of the source point;
- initial directory angle;
- horizontal angles;
- The length of the parties.
Field measurements made even when complying with all rules and requirements, will have inaccuracies. They are due to systematic and technical errors, as well as a human factor.
Calculations are carried out in a specific sequence, which will look further.
Equalization
At the beginning of the calculations, the theoretical amount of the corners is determined, and then linked them, distributing the angular residiousness between them.
\\ (\\ Sum \\ Beta _ (theore) \u003d 180 ^ (\\ CIRC) \\ CDOT (N-2) \\)
n- Number of polygon points;
\\ (F _ (\\ Beta) \u003d \\ Sum \\ Beta _ (Izm) -180 ^ (\\ CIRC) \\ CDOT (N-2) \\)
\\ (\\ sum \\ beta _ (measuring) \\) - the value of the measured angular values;
To obtain \\ (F _ (\\ beta) \\), it is necessary to calculate the difference between \\ (\\ beta _ (measuring) \\), in which errors are present, and \\ (\\ sum \\ beta _ (theore) \\).
In the equalization \\ (F _ (\\ beta) \\), it acts as an indicator of the accuracy of the measuring work, and its value should not be higher than the limit value determined from the following formula:
\\ (F _ (\\ Beta 1) \u003d 1,5t \\ SQRT (N) \\)
t-accuracy of the measuring device,
N - Number of corners.
The equalization ends with a uniform distribution of the resulting residual between the angular values.
Definition of directory corners
With the known value of the directorate angle (\\ (\\ alpha \\)) of one side and horizontal (\\ (\\ beta \\)), you can determine the following side:
\\ (\\ alpha _ (n + 1) \u003d \\ alpha _ (n) + \\ ETA \\)
\\ (\\ ETA \u003d 180 ^ (\\ CIRC) - \\ Beta _ (PR) \\)
\\ (\\ beta _ (pr) \\) - the value of the right in the direction of the angle, from which it follows:
\\ (\\ alpha _ (n + 1) \u003d \\ alpha _ (n) +180 ^ (\\ CIRC) - \\ Beta _ (PR) \\)
For the left (\\ (\\ beta _ (lion) \\)) these signs will be opposite:
\\ (\\ alpha _ (n + 1) \u003d \\ alpha _ (n) -180 ^ (\\ CIRC) + \\ Beta _ (Lion) \\)
Since the value of the directorate angle cannot be greater than \\ (360 ^ (\\ CIRC) \\), then from it, respectively, are torn \\ (360 ^ (\\ CIRC) \\). In the case of a negative angle, it is necessary to add to the previous \\ (\\ alpha \\) to add \\ (180 ^ (\\ CIRC) \\) and take the value \\ (\\ beta _ (rear) \\).
Calculation of Rumbs
Rugs and directive angles there is a relationship, and determine them in quarters, which are called the name of the four sides of the world. As can be seen from Table 1. Calculations are carried out according to the established scheme.
Table 1. Rumbal calculations depending on the limits of the directory angle.
The increment of coordinates
For the increments of coordinates in a closed course, formulas used in solving a direct geodesic problem are used. Its essence is that, according to the known values \u200b\u200bof the coordinates of the source point, the directive angle and the horizontal application, the coordinates of the next one can determine the coordinates of the following. Based on this, the formula of the increment of values \u200b\u200bwill have the following form:
\\ (\\ Delta X \u003d D \\ CDOT COS \\ ALPHA \\)
\\ (\\ Delta y \u003d d \\ cdot sin \\ alpha \\)
d-horizontal paugulation;
α-horizontal angle.
For a landfill, which has the form of a closed geometric shape, the theoretical amount of increments will be zero for both coordinate axes:
\\ (\\ SUM \\ DELTA X_ (TheOR) \u003d 0 \\)
\\ (\\ Sum \\ Delta y_ (theore) \u003d 0 \\)
Linear non-lack and non-infection of the increment of coordinate values
Despite the foregoing, random errors do not allow algebraic amounts to go out in zero, so they will be equal to other residual coordinate increments:
\\ (F_ (X) \\ Sum_ (i \u003d 1) ^ (n) \\ Delta x_ (1) \\)
\\ (F_ (y) \\ Sum_ (i \u003d 1) ^ (n) \\ Delta y_ (1) \\)
Variables \\ (F_ (x) \\) and \\ (F_ (y) \\) - Projections of linear residual \\ (F_ (P) \\) on the coordinate axis, which can be calculated by the formula:
\\ (F_ (P) \u003d \\ SQRT (F_ (X) ^ (2) + F_ (Y) ^ (2)) \\)
In this case, \\ (F_ (P) \\), should not be more than 1/2000 on the share of the perimeter of the polygon, and the distribution \\ (F_ (x) \\) and \\ (F_ (y) \\) is carried out as follows:
\\ (\\ Delta x_ (i) \u003d - \\ FRAC (F_ (X)) (p) d_ (i) \\)
\\ (\\ Delta y_ (i) \u003d - \\ FRAC (F_ (Y)) (p) d_ (i) \\)
In these formulas \\ (\\ delta x_ (i) \\) and \\ (\\ deelta y_ (i) \\) - corrections of the increment of coordinates.
_ numbers numbers;
In the calculations, it is important not to forget about the values \u200b\u200bof the algebraic amount, in other words - signs. When amendments, they must be opposed to the signs of residuals.
After increments and amendments to the measurement data, they calculate their corrected values.
Calculation of coordinates
When the involvement of the increments of the polygon points are made, the coordinate should be determined, which is carried out using the following formulas:
\\ (X_ (PR) \u003d X_ (PR) + \\ Delta X_ (PS) \\)
\\ (Y_ (pos) \u003d y_ (pr) + \\ Delta y_ (PC) \\)
The values \u200b\u200b\\ (x_ (pos) \\) \\ (y_ (pos) \\) are the coordinates of subsequent paragraphs, \\ (x_ (pr) \\) and \\ (y_ (pr) \\) - previous.
\\ (\\ Delta X_ (PS) \\) and \\ (\\ Delta y_ (PS) \\) - corrected increments between these two values.
If the coordinates of the first and last point coincide, then the processing can be considered completed.
Based on the coordinates and drawn up during field measurements of the abrasions, a theodolite stroke plan is further compiled.
B. 1.2.1: The division of the horizon for degrees and rumba relative to the diametrical plane of the vessel. How many degrees contains one RUMB? The main 8 rumbes.
A: The true horizon is divided into course angles from the DP of the vessel to 180 ° left and right side, and in Rumbach on 16 Rumbes of the left and right Borg. One RUMB is 11.25 °. The horizon is divided into 360 "or 32 Rumba, the main 8 of them are called Nord (N), Nord-Ost (NE), OST (E), South Ost (SE), South (S), South West (SW), West (W), Nord-West (NW).
B.1.2.2: Responsibilities for visual observation. Dangerous surveillance horizon sectors.
O: On the move, the observation is carried out constantly throughout the horizon with the use of binoculars; Special attention is paid to the directions directly on the nose to the traverse (90 °) of the right and left side, while the Sector on the right Bore is most dangerous when discrepancies with the courts. On the detection of a particular object, lights (in the dark), it is necessary to take on it a bearing in degrees or determine the course angle (the difference between the vessel's course and the directionler or to remove Ku on the azimtal circle according to the refinery of the Civil Code) and report to the Watch Officer the result! Observations. The observer should also inspect the surface of the sea for possible detection of rescue with people who endure disaster, or people who fell overboard.
B. 1.2.3: Form of the observer report by a timing officer about the objects detected
ABOUT:
1st - what I see;
2nd - Kuro angle on volume;
3rd - Cable Distance,
One cables \u003d 0.1 miles \u003d L85.3 meters.
B.1.2.4: Fogging means of foggy signals. Variants characteristics of signals.
A: Foggy signals are fed by such means as a beep (whistle), Horn, ship bell, gong, siren, etc. Possible variants of characteristics of signals:
one long (------) - 4-6 seconds;
two long (----- -----);
One long and after him two short (--- * *);
one long and after him three short (----- * * *);
One short, one long, one short (* ---- *);
four short sounds (* * * *);
Bells - frequent blows in the bell within 5 SSK or complementing its frequent hong blows. According to the observer report, the Watch officer determines the object that gives these signals. However, it is also recommended that the observer independently determine objects supplying foggy signals, according to their characteristics.
