Method for measuring building facade through three-dimensional coordinate conversion

Abstract

The invention discloses a method for measuring a building facade through three-dimensional coordinate transformation. The method specifically comprises the steps of establishing a relative coordinate system, establishing a coordinate system in parallel, measuring point coordinates, rotating the coordinate system, calculating the point coordinates and drawing a facade map. According to the method, a total station is used for carrying out station setting according to a set coordinate system, building facade feature points are measured, obtained measurement data are subjected to coordinate rotation, facade data are converted into feature point parameters capable of being directly expanded and drawn, and a building facade map can be obtained after expansion and drawing; during actual operation, actual station setting and measurement can be completed only once, data are more accurate, operation is simpler, and the workload of data conversion and processing is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of construction measurement, and in particular to a method for measuring building facades through three-dimensional coordinate conversion. Background Art

[0002] With the advancement of urban renewal, there are more and more building renovation projects. Many buildings are very old and the drawings are not well preserved. If you want to carry out in-depth design, building facade measurement is the only way to obtain the current status of the building. Traditional building facade measurement requires the erection of an external protective frame and manual climbing and measurement with a ruler. This method is not safe and has low work efficiency. A more advanced method is to use a three-dimensional laser scanning method to scan the building point cloud. For example, the technical solution of the CN108776738A building facade surveying method is to draw based on the facade point cloud tracing, but this method requires the purchase of three-dimensional laser scanning equipment, which is expensive and not suitable for technology promotion.

[0003] Therefore, a method of using a total station to measure the facade has emerged, such as CN105241432A, which uses a total station to measure, then processes the measurement data, and finally obtains the facade of the building. However, the above method is cumbersome to operate, and requires high operating accuracy, and cannot be conveniently surveyed and mapped. The present invention provides a method for measuring the facade of a building through three-dimensional coordinate conversion to solve the above problem. Summary of the invention

[0004] The invention provides a method for measuring building facades through three-dimensional coordinate conversion, which uses a total station to measure and realizes coordinate conversion through coordinate system conversion, and the measured data can be used for display and obtaining a building facade drawing.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: A method for measuring building facades through three-dimensional coordinate transformation comprises the following steps: S1, establish relative coordinate system: establish relative coordinate system O'-X'Y'Z' based on the direction of the building; S2, establish a parallel coordinate system: based on the relative coordinate system O'-X'Y'Z', establish a coordinate system O-XYZ that is parallel to it; S3, measuring point coordinates: based on the coordinate system O-XYZ, measure the parameters of the feature point M on the building facade through the total station, and calculate the point coordinates (x, y, z) of the feature point M; S4, rotate the coordinate system: rotate the X axis of the coordinate system O-XYZ by 90° and interchange it with the Z axis to rotate the coordinate system; S5, calculate the point coordinates: after the coordinate system O-XYZ is rotated, the feature point M on it becomes the feature point M' after rotation, and the point coordinates (z, y, x) of the feature point M' are calculated; S6, draw the elevation drawing: measure and calculate the building elevation points, and draw all the new coordinate points obtained in the mapping software, and then draw the building elevation drawing according to the sketch.

[0006] Furthermore, in step S1, the relative coordinate system O'-X'Y'Z' is established based on the orientation of the building, with the horizontal long side of the building facade to be mapped as the Y' axis, the relatively vertical horizontal side as the X' axis, and the direction perpendicular to the ground as the Z' axis.

[0007] Furthermore, in step S2, when the coordinate system O-XYZ is established, translation is performed along the direction of O'-X'.

[0008] Furthermore, in step S3, the point coordinates (x, y, z) of the feature point M are calculated as follows: Where r is the straight-line distance between feature point M and coordinate point O, θ is the angle between r and the Z axis, and Φ is the angle between r and the X axis. The values ​​of Xm, Ym, and Zm are the point coordinates (x, y, z) of M.

[0009] Furthermore, in step S5, the point coordinates of the feature point M' are calculated by multiplying the initial coordinates of the feature point M by the rotation matrix R. The specific calculation formula is as follows: , Where x, y, z are the values ​​of the initial coordinates of the feature point M, X, Y, Z are the values ​​of the coordinates of the feature point M' after rotation, and a1, a2, a3, b1, b2, b3, c1, c2, c3 are the parameters of the rotation matrix R.

[0010] Furthermore, when the rotation is performed according to step S4, the specific form of the rotation matrix R is: .

[0011] The beneficial effects of the present invention are as follows: Use the total station to set up the station according to the set coordinate system, measure the characteristic points of the building facade, rotate the coordinates of the obtained measurement data, and convert the facade data into characteristic point parameters that can be directly displayed. After display, the building facade drawing can be obtained. In actual operation, the actual station setting and measurement only need to be done once to complete the measurement, and the data is more accurate, the operation is simpler, and the workload of data conversion and processing is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of establishing a relative coordinate system of the present invention; Figure 2 It is a schematic diagram of calculating the side length when the building of the present invention is parallel to the coordinate system; Figure 3 It is a schematic diagram of calculating the side length when the building of the present invention is not parallel to the coordinate system; Figure 4 It is a schematic diagram of coordinate system translation of the present invention; Figure 5 It is a schematic diagram of the coordinate calculation principle of the present invention; Figure 6 It is a schematic diagram of the rotation of the coordinate system of the present invention; Figure 7 It is a schematic diagram of the measurement points of building feature points of the present invention; Figure 8 This is a schematic diagram of the position of building feature points after rotation calculation according to the present invention. DETAILED DESCRIPTION

[0013] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings of the specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0014] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0015] like Figure 1 , 4As shown in Figures 5 and 6, when a total station is used for surveying, conventional single-point surveying data cannot form effective parameters, and continuous surveying is required to obtain a usable data set. Moreover, since the total station surveys the main elevation of the building, but when it is displayed on the drawing, it is displayed in a bird's-eye view. Therefore, the coordinates measured by the total station cannot be used directly, and the data need to be converted manually before being displayed. However, since the continuous surveying data is large, and the accuracy of the data needs to be ensured when processing the continuous surveying data, the workload is extremely large, which makes the conventional surveying method have great defects when used. The method of measuring the facade of a building by three-dimensional coordinate conversion of the present invention specifically includes the steps of establishing a relative coordinate system, establishing a coordinate system in parallel, measuring point coordinates, rotating the coordinate system, calculating point coordinates and drawing a facade. Through the above steps, the building facade to be measured can be directly obtained and displayed on the drawing, which not only ensures the accuracy of the data, but also greatly reduces the workload.

[0016] like Figure 1 As shown, step S1, establish a relative coordinate system: establish a relative coordinate system O'-X'Y'Z' based on the direction of the building. When establishing the relative coordinate system O'-X'Y'Z', it is necessary to use the direction of the building, with the horizontal long side of the building facade to be measured as the Y' axis, the relatively vertical horizontal side as the X' axis, and the direction perpendicular to the ground as the Z' axis, so as to ensure the accuracy of the measurement of the facade drawing. When drawing and calculating, there is no need to consider the influence of the rotation angle on the distance, which makes measurement and calculation simpler and the data more accurate.

[0017] When the relative coordinate system O'-X'Y'Z' is set up parallel to the building, such as Figure 2 As shown in the O'-X'Y' plane coordinate system, the measured building length c=ad at this time does not need to consider the change in distance caused by angle rotation, and the calculation is simpler. When the relative coordinate system O'-X'Y'Z' is not parallel to the building, such as Figure 3 As shown in the O'-X'Y' plane coordinate system, the coordinate value a is equal to the projection length of the side length 0m on the X-axis after rotating by an angle of Φ, that is, Oa=Om*cosΦ. This will affect the measured length of the building, that is, the measured coordinate value ad is only the projection length of c on the X-axis, not the actual side length c of the building, and the actual side length c=(ad) / cosΦ.

[0018] like Figure 4 As shown, step S2, establish a parallel coordinate system: based on the relative coordinate system O'-X'Y'Z', translate an arbitrary distance along the direction of O'-X' to establish a coordinate system O-XYZ parallel to the relative coordinate system. When translating, make point O located on the extension line of O'-X', and the specific translation distance is determined according to the elevation angle of the building height.

[0019] like Figure 5 As shown, step S3, measuring point coordinates: based on the coordinate system O-XYZ, the parameters of the feature point M on the facade of the building are measured by a total station, and the point coordinates (x, y, z) of the feature point M are calculated.

[0020] The point coordinates (x, y, z) of the feature point M are calculated as follows: Where r is the straight-line distance between feature point M and coordinate point O, θ is the angle between r and the Z axis, Φ is the angle between r and the X axis, YO and XO are the relative coordinate values ​​of coordinate point O, S is the projection of r on the XY plane, The values ​​of Xm, Ym, and Zm are the point coordinates (x, y, z) of M.

[0021] When drawing a facade drawing, the coordinate values ​​on the Z axis and the Y axis are required. However, when surveying and drawing, the coordinate values ​​drawn on the drawing are X and Y, and the Z value is only marked on the drawing, which makes it impossible to draw the facade drawing directly. Through step S4, the coordinates are rotated: the X axis of the coordinate system O-XYZ is rotated 90° and interchanged with the Z axis, the coordinate system is rotated, and the value in the Z direction is converted into the value of X for drawing. The result of the drawing is the facade direction of the building.

[0022] like Figure 6 As shown, step S5, calculate the point coordinates: after the coordinate system O-XYZ is rotated, the feature point M thereon becomes the feature point M' after rotation, and the point coordinates (z, y, x) of the feature point M' are calculated.

[0023] The point coordinates of the feature point M' are calculated by multiplying the initial coordinates of the feature point M by the rotation matrix R. The specific calculation formula is as follows: , Where x, y, z are the values ​​of the initial coordinates of the feature point M, X, Y, Z are the values ​​of the coordinates of the feature point M' after rotation, and a1, a2, a3, b1, b2, b3, c1, c2, c3 are the parameters of the rotation matrix R; After calculation, the coordinates of the feature point M' obtained by the values ​​of X, Y, and Z are (z, y, x).

[0024] Further, when the coordinates are rotated according to the rotation method of step S4, that is, the X-axis of the coordinate system O-XYZ is rotated 90° and interchanged with the Z-axis, when the coordinate system is rotated, the specific form after the parameters a1, a2, a3, b1, b2, b3, c1, c2, and c3 of the rotation matrix R in step S5 are selected is: , The final matrix for coordinate system rotation is: , The result of the operation is: , The point coordinates (z, y, x) of the obtained feature point M'.

[0025] Step S6, drawing the elevation drawing: measuring and calculating the building elevation points, and plotting all the obtained new coordinate points in the mapping software, and then drawing the building elevation drawing according to the sketch.

[0026] In a specific embodiment of the present invention, the four corners of a building are measured, and the measurement results of the four corners are as follows: Figure 7 As shown in the figure, since the x coordinates of the four corners are all 1000, they cannot be drawn after the points are expanded. After rotating the X axis of the coordinate system O-XYZ by 90° and exchanging it with the Z axis, the coordinates of the four corners are calculated as follows: Figure 8 As shown, if it meets the exhibition requirements, the drawing can be completed.

[0027] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A method for measuring building facades by three-dimensional coordinate transformation, characterized in that: The following steps are involved: S1, establish relative coordinate system: establish relative coordinate system O'-X'Y'Z' based on the direction of the building; S2, establish a parallel coordinate system: based on the relative coordinate system O'-X'Y'Z', establish a coordinate system O-XYZ that is parallel to it; S3, measuring point coordinates: based on the coordinate system O-XYZ, measure the parameters of the feature point M on the building facade through the total station, and calculate the point coordinates (x, y, z) of the feature point M; S4, rotate the coordinate system: rotate the X axis of the coordinate system O-XYZ by 90° and interchange it with the Z axis to rotate the coordinate system; S5, calculate the point coordinates: after the coordinate system O-XYZ is rotated, the feature point M on it becomes the feature point M' after rotation, and the point coordinates (z, y, x) of the feature point M' are calculated; S6, draw the elevation drawing: measure and calculate the building elevation points, and draw all the new coordinate points obtained in the mapping software, and then draw the building elevation drawing according to the sketch.

2. The method for measuring building facades by three-dimensional coordinate transformation according to claim 1, characterized in that: In step S1, the relative coordinate system O'-X'Y'Z' is established based on the direction of the building, with the horizontal long side of the building facade to be mapped as the Y' axis, the relatively vertical horizontal side as the X' axis, and the direction perpendicular to the ground as the Z' axis.

3. The method for measuring building facades by three-dimensional coordinate transformation according to claim 1, characterized in that: In step S2, when establishing the coordinate system O-XYZ, translation is performed along the direction of O'-X'.

4. The method for measuring building facades by three-dimensional coordinate transformation according to claim 1, characterized in that: In step S3, the point coordinates (x, y, z) of the feature point M are calculated as follows: Where r is the straight-line distance between the feature point M and the coordinate point O, θ is the angle between r and the Z axis, Φ is the angle between r and the X axis, and the values ​​of Xm, Ym, and Zm are the point coordinates (x, y, z) of M.

5. The method for measuring building facades by three-dimensional coordinate transformation according to claim 1, characterized in that: In step S5, the point coordinates of the feature point M' are calculated by multiplying the initial coordinates of the feature point M by the rotation matrix R. The specific calculation formula is as follows: ， Where x, y, z are the values ​​of the initial coordinates of the feature point M, X, Y, Z are the values ​​of the coordinates of the feature point M' after rotation, and a1, a2, a3, b1, b2, b3, c1, c2, c3 are the parameters in the rotation matrix R.

6. The method for measuring building facades by three-dimensional coordinate transformation according to claim 5, characterized in that: When the rotation is performed according to step S4, the specific form of the rotation matrix R is: 。

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