Method for Adapting City-Level BIM to the Earth's Curvature

Abstract

The present invention relates to a method for adapting BIM at the urban scale to the earth's curvature. BIM includes a planar coordinate system, and GIS includes a geographic coordinate system under the earth's curvature. The method comprises the following steps: taking a reference coordinate point O in the planar coordinate system and a reference coordinate point O1 in the geographic coordinate system, and making the reference coordinate point O coincide with the reference coordinate point O1; obtaining any point P0 to be converted in the planar coordinate system; setting the z value of the point P0 to be converted to 0, that is, obtaining the projection point P1 of the point P0 to be converted; obtaining a point P2 in the geographic coordinate system with a z value of 0, such that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O, and the projection of the line where the projection point P1 is located to the reference coordinate point O falls on the arc where the point P2 is located to the reference coordinate point O1; adding the z value to the point P2 to obtain a point P3, and the point P3 is the point corresponding to the point P0 to be converted in the geographic coordinate system. The present invention enables the precise matching of BIM and GIS data affected by the earth's curvature, and avoids problems such as cracks and holes during rendering.

Description

Technical Field

[0001] The present invention relates to the technical field of geophysical exploration, and particularly relates to a method and application for adapting BIM at the urban scale to the earth's curvature. Background Art

[0002] Most of the existing modeling software currently is for planar modeling (such as BIM), and then the built model is placed on the earth. If the model is extremely long, with a span of several kilometers or even dozens of kilometers, there will be a phenomenon that one or both ends of the model are far from the ground, which is the so-called problem of both ends tilting up, as Figure 1 shown. The reason for this problem is that the earth itself has curvature, while the model is for planar modeling. Therefore, for such an extremely long model, we need to recalculate the model data of the model under the earth's curvature.

[0003] BIM (Building Information Modeling) usually adopts an independent planar coordinate system. GIS (Geographic Information System) has numerous data sources, different acquisition methods, and there are also certain differences in the coordinate systems it adopts. It can be seen that the integrated application of BIM and GIS faces the problem that their respective coordinate systems are different and difficult to match. The most basic ability of GIS is coordinate transformation, and the coordinate transformation of points, lines, and planes is already very mature, but whether the transformation ability can be applied to three-dimensional model data is also a challenge for the GIS platform.

[0004] Therefore, it is necessary to provide a method and application for adapting BIM at the urban scale to the earth's curvature to achieve precise matching of BIM and GIS data under the influence of the earth's curvature and avoid problems such as cracks and holes during rendering. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and application for adapting BIM at the urban scale to the earth's curvature to achieve precise matching of BIM and GIS data under the influence of the earth's curvature and avoid problems such as cracks and holes during rendering.

[0006] To solve the problems existing in the prior art, the present invention provides a method for adapting BIM at the urban scale to the earth's curvature. BIM includes a planar coordinate system, and GIS includes a geographic coordinate system under the earth's curvature, and the method includes the following steps:

[0007] Take the reference coordinate point O in the planar coordinate system and the reference coordinate point O1 in the geographic coordinate system, and make the reference coordinate point O and the reference coordinate point O1 coincide;

[0008] Obtain any point P0 to be transformed in the planar coordinate system;

[0009] Set the z value of the point P0 to be converted to 0, that is, obtain the projection point P1 of the point P0 to be converted on the plane where the reference coordinate point O is located;

[0010] Obtain a point P2 with a z value of 0 in the geographic coordinate system, so that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O, and the projection of the projection point P1 on the straight line where the reference coordinate point O is located falls on the arc from the point P2 to the reference coordinate point O1;

[0011] Add the z value that has been set to 0 to the point P2 to obtain the point P3. The point P3 is the corresponding point of the point P0 to be converted in the geographic coordinate system, and the conversion is completed.

[0012] Optionally, in the method for adapting the city-level BIM to the earth's curvature, set the z value of the point P0(x0, y0, z0) to be converted to 0, and the coordinates of the projection point P1 are obtained as (x0, y0, 0).

[0013] Optionally, in the method for adapting the city-level BIM to the earth's curvature, obtain a point P2 with a z value of 0 in the geographic coordinate system, so that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O. The calculation method of the coordinates of the point P2 is as follows:

[0014] Taking the earth's center point as the center of the circle, the central angle corresponding to the arc where the reference coordinate point O1 and the point P2 are located is θ. The calculation formula for the central angle θ is:

[0015] where R is the radius of the earth;

[0016] Then calculate the coordinates (x2, y2, z2) of the point P2:

[0017] z2 = R * cosθ - R.

[0018] Optionally, in the method for adapting the city-level BIM to the earth's curvature, add the z value that has been set to 0 to the point P2 to obtain the coordinates (x3, y3, z3) of the point P3. The calculation formula is as follows:

[0019] z3 = (R + z0) * cosθ - R.

[0020] Optionally, in the method for adapting the city-level BIM to the earth's curvature,

[0021] The models including the plane coordinate system include but are not limited to BIM.

[0022] The present invention also provides an application of adapting urban-scale BIM to the earth's curvature. By using the method of adapting urban-scale BIM to the earth's curvature, the method is deployed on the server side or the client side to obtain the coordinates before or after conversion.

[0023] Optionally, in the application of adapting urban-scale BIM to the earth's curvature, the application scenarios include, but are not limited to, the construction of bridges, roads, and water conservancy dams.

[0024] In the method and application of adapting urban-scale BIM to the earth's curvature provided by the present invention, point-by-point coordinate conversion of the 3D model can be realized, supporting the conversion of BIM and GIS data between the plane coordinate system and the geographic coordinate system, achieving precise matching of BIM and GIS data under the influence of the earth's curvature, avoiding problems such as cracks and loopholes during rendering, and meeting the accuracy requirements of data in the construction, operation, and management processes of many industries, such as bridges, roads, and water conservancy dams. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the model placed on the earth in the background art provided by the embodiment of the present invention;

[0026] Figure 2 and Figure 3 It is a schematic diagram of the calculation process of the adaptation method provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will describe the specific embodiments of the present invention in more detail with reference to the schematic diagrams. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0028] In the following text, if the method described in this article includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be executed, and some of the described steps can be omitted and / or some other steps not described herein can be added to the method.

[0029] Since the integrated application of BIM and GIS faces the problem that their respective coordinate systems are different and difficult to match. The most basic ability of GIS is coordinate conversion, and the coordinate conversion of points, lines, and surfaces is already very mature, but whether the conversion ability can be applied to 3D model data is also a challenge for the GIS platform.

[0030] To solve the problems existing in the prior art, the present invention provides a method for adapting urban-scale BIM to the earth's curvature. BIM includes a plane coordinate system, and GIS includes a geographic coordinate system under the earth's curvature, including the following steps:

[0031] Take the reference coordinate point O in the plane coordinate system and the reference coordinate point O1 in the geographic coordinate system, and make the reference coordinate point O coincide with the reference coordinate point O1;

[0032] Obtain any point P0 to be converted in the plane coordinate system;

[0033] Set the z value of the point P0 to be converted to 0, that is, obtain the projection point P1 of the point P0 to be converted on the plane where the reference coordinate point O is located;

[0034] Obtain a point P2 with a z value of 0 in the geographic coordinate system, so that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O, and the projection of the projection point P1 on the straight line where the reference coordinate point O is located falls on the arc where the point P2 to the reference coordinate point O1 is located;

[0035] Add the z value set to 0 to the point P2 to obtain the point P3, and the point P3 is the corresponding point of the point P0 to be converted in the geographic coordinate system, and the conversion is completed.

[0036] The present invention simplifies the conversion formula, so that BIM data can be calculated in real time according to needs during the rendering process, with a fast operation speed and a good conversion effect.

[0037] Further, as Figure 2 shown, set the z value of the point P0(x0, y0, z0) to be converted to 0, and the coordinates of the projection point P1 are obtained as (x0, y0, 0).

[0038] Obtain a point P2 with a z value of 0 in the geographic coordinate system, so that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O. The calculation method of the coordinates of the point P2 is as follows:

[0039] Taking the earth center point as the center of the circle, the central angle corresponding to the arc where the reference coordinate point O1 and the point P2 are located is θ, and the calculation formula of the central angle θ is:

[0040] where R is the radius of the earth;

[0041] Then calculate the coordinates (x2, y2, z2) of the point P2, using similar triangles:

[0042] It can be obtained that:

[0043] Similarly, it can be obtained that: z2 = R * cosθ - R.

[0044] Even further, referring to Figure 3 , add the z value set to 0 to the point P2 to obtain the coordinates (x3, y3, z3) of the point P3, and also use similar triangles:

[0045]

[0046] Similarly, it can be obtained that: z3 = (R + z0) * cosθ - R.

[0047] Preferably, in the method for adapting urban-scale BIM to the earth's curvature, the models including the planar coordinate system include but are not limited to BIM.

[0048] The present invention also provides an application of adapting urban-scale BIM to the earth's curvature. By using the method for adapting urban-scale BIM to the earth's curvature, the method is deployed on the server side or the client side to obtain the coordinates before or after conversion.

[0049] Specifically, the method can be deployed on the server side. When the user uploads model data, the method can be enabled according to needs. For example, when the user's model data needs to be displayed in the GIS system, then this method can be enabled, so as to convert the model data uploaded by the user into model data suitable for display in the GIS system. The advantage of deploying on the server side is that the client can directly use the GIS model data when using it, without the need for recalculation.

[0050] Of course, the method can also be deployed on the client side. The advantage compared with the server side is that it is more flexible. The client can decide whether to display in the 3D GIS system according to needs, and then select whether to perform real-time coordinate conversion according to needs. At this time, the calculation is performed in the CPU.

[0051] Because the model data ultimately needs to be sent to the GPU for rendering and drawing, the method can be slightly modified and also embedded into the program executed in the GPU. Compared with the client-side solution, the operation efficiency of the GPU is higher, so that the performance consumption of the method for real-time rendering is minimized, and the performance consumption of the conversion can be almost ignored.

[0052] Generally, in the web environment, through the earth provided in the cesium framework, the present invention can apply the curvature calculation formula of the method to any ultra-long model to obtain the required conversion data.

[0053] At the same time, because the calculation amount of the present invention is small and it is easy to deploy, it can meet the coordinate conversion of a large amount of BIM data during real-time rendering.

[0054] Optionally, in the application of adapting urban-scale BIM to the earth's curvature, the application scenarios include but are not limited to the construction of bridges, roads, and water conservancy dams.

[0055] In summary, in the method and application of adapting BIM at the urban scale to the earth's curvature provided by the present invention, point-by-point coordinate conversion of three-dimensional models can be achieved, supporting the conversion of BIM and GIS data between the plane coordinate system and the geographic coordinate system, realizing the precise matching of BIM and GIS data under the influence of the earth's curvature, avoiding problems such as cracks and holes during rendering, and meeting the precision requirements of data in the construction, operation, and management processes of many industries, such as bridges, roads, and water conservancy dams.

[0056] The above are only the preferred embodiments of the present invention and do not impose any limitation on the present invention. Any person skilled in the art within the technical field, without departing from the scope of the technical solution of the present invention, making any form of equivalent replacement or modification and other changes to the disclosed technical solution and technical content of the present invention shall fall within the content of the technical solution of the present invention and still be within the protection scope of the present invention.

Claims

1. A method for adapting BIM at the urban scale to the earth's curvature, characterized in that, BIM includes a planar coordinate system, and GIS includes a geographic coordinate system under the earth's curvature, including the following steps: Take the reference coordinate point O in the planar coordinate system and the reference coordinate point O1 in the geographic coordinate system, and make the reference coordinate point O and the reference coordinate point O1 coincide; Obtain any point P0 to be converted in the planar coordinate system; Set the z value of the point P0 to be converted to 0, that is, obtain the projection point P1 of the point P0 to be converted on the plane where the reference coordinate point O is located; among them, when the z value of the point P0(x0, y0, z0) to be converted is set to 0, the coordinates of the projection point P1 are (x0, y0, 0); Obtain a point P2 with a z value of 0 in the geographic coordinate system, so that the arc length from the point P2 to the reference coordinate point O1 is equal to the distance value from the projection point P1 to the reference coordinate point O, and the projection of the projection point P1 on the straight line where the reference coordinate point O is located falls on the arc where the point P2 to the reference coordinate point O1 is located; Among them, the calculation method of the coordinates of point P2(x2, y2, z2) is as follows: Taking the center of the earth as the center of the circle, the central angle corresponding to the arc where the reference coordinate point O1 and point P2 are located is θ, and the calculation formula of the central angle θ is: where R is the radius of the earth; then calculate the coordinates (x2, y2, z2) of point P2: z2 = R * cosθ - R; Add the z value set to 0 to the point P2 to obtain the point P3, and the point P3 is the corresponding point of the point P0 to be converted in the geographic coordinate system, and the conversion is completed; Among them, the calculation method of the coordinates of point P3(x3, y3, z3) is as follows: z3 = (R + z0) * cosθ - R.

2. The method for adapting BIM at the urban scale to the earth's curvature according to claim 1, wherein The model including the planar coordinate system includes BIM.

Images