What are the main methods of measuring and setting out the main axis of a building?

In engineering construction, the most widely used measurement procedure is lofting. It plays a central role in the construction. Without lofting, all our projects can't be constructed normally. Therefore, the application of lofting program plays an important role in engineering construction. Therefore, it is also the most basic thing that every surveyor must do in order to better master the application of lofting program.

The lofting procedure may encounter different situations in different construction units. Generally speaking, there are three main situations:

① There are two known points in the survey area.

When there are two or more control points in our survey area and visibility can be achieved, we enter the "lofting" procedure. First of all, we set up the station (that is, enter the station coordinates, elevation, instruments and other information), and then we enter the "rear view setting" (just enter its coordinates). Finally, we must confirm the viewpoint after "accurate" aiming, and then we can complete the backward-looking orientation. Next, we can set the design coordinates.

② There is only one known point in the survey area, but the azimuth is known.

If our survey area has only one control point, but has a known azimuth, we can also release other points like the last one. First of all, enter the "lofting" program and set up the station. Next, when we enter the "rear viewpoint setting", we will choose the "angle" mode instead of the "coordinate" mode (in the series of total stations such as Su Yiguang RTS632, Southern NTS322, Topcon GTS332, etc., after entering the "rear viewpoint setting", select "coordinate" and then proceed to the next step to start lofting after the rear viewpoint orientation is completed.

③ There are no known points in the survey area.

If we have no control points in the survey area during construction, this situation mainly occurs in the construction unit. In this case, we can customize the coordinate system, erect the instrument on the main line point of the building grid, and then establish an independent building coordinate system with the other main line direction as the true north direction.

⑴ We assume the coordinates of a station, enter our customized coordinates after entering Station Settings, then enter Rear View Settings, aim at our customized true north direction, use the angle mode to orient, enter the azimuth angle of 0 degrees, and then "confirm" to view the azimuth. Finally, for the design points on the drawing, the coordinates of each point in our custom coordinate system are calculated, and the coordinates are used for field calibration.

⑵ We can use the method of theodolite lofting to calculate the distance between the lofting point and the measuring site and the angle with the back viewpoint, set the horizontal angle of the back viewpoint direction to zero, and determine the point by rotating the angle and ranging.

I intermodulation between "coordinate data file" and "measurement data file" in lofting and data acquisition;

1, in the lofting program, the point instruments we put are all known coordinate points by default, so even if we enter the coordinates of the points ourselves in the lofting process, we can't enter the number of the points. And only the data in the "coordinate data file" can be retrieved when retrieving data.

2. If all the data of the points we put in are in the "survey data file", we will "select the file" when we start to retrieve the required data. After entering the "lofting" program, press the page turn key to enter the second page, and then select "Select File" to select "Survey Data File" from its list. Finally, go back to the previous page and enter "lofting", so that we can retrieve the data stored in the "survey data file" for lofting.

3. In the "data acquisition" program, we need to collect the information of points without coordinates on the ground. Therefore, in this program, we must input the point number of the measured point before measurement, otherwise the instrument will not allow us to measure. If the height of the prism changes during the measurement, we must correct the height of the mirror before the measurement, and the measurement results will be automatically stored in the memory.

4. In Japanese Soja and Su Guang 602 series (like Soja) total station, the data in "measurement data file" and "coordinate data file" in memory can be directly retrieved, which improves the work efficiency. And in data acquisition, we can measure first, and when the measurement results are displayed, we can also correct the prism height, and then save the results in memory, thus reducing the probability of errors.