A method for making a three-dimensional high-precision map of a park based on BIM technology

Abstract

The present invention discloses a method for making a three-dimensional high-precision map of a park based on BIM technology. First, BIM design is performed on the park features; secondly, a local coordinate system of the park plane is established, two or more feature points are selected and their local coordinates are determined, so as to determine the translation parameters of the local coordinate system after Gaussian projection transformation; thirdly, the BIM model is format-converted as a whole, imported into 3Dmax for material mapping, and then packaged as a whole, and then imported into a graphics rendering platform to complete a static three-dimensional high-precision map; in addition, the feature points are marked and the coordinate values ​​are recorded on site simultaneously, the meridian of this Gaussian projection transformation is determined according to the area where the park is located, and a Gaussian projection forward calculation model is established; finally, the plane translation parameters are calculated according to the local coordinate values ​​and ellipsoid coordinate values ​​of the feature points, and then the conversion equation between the ellipsoid coordinate system and the local coordinate system is determined, so as to realize the plane matching of the positioning data with the three-dimensional high-precision map.

Description

Technical Field

[0001] The present invention relates to the technical field of producing three-dimensional high-precision maps of a park, and in particular to a method for producing a three-dimensional high-precision map of a park based on BIM technology. Background Art

[0002] With the development of digital technology, some new park projects have proposed digital park management solutions for the operation and maintenance period during the planning and design stage, requiring the digital operation and maintenance platform to be delivered at the same time as the project infrastructure. As the basic base of the park's digital platform, the park-level three-dimensional high-precision map undertakes the functions of three-dimensional display roaming of the digital park, information attachment of IoT sensing equipment, high-precision positioning of mobile objects, playback of mobile object historical trajectories, and three-dimensional functional scene simulation. Therefore, it is necessary to develop and design it synchronously with the park's digital management platform before the infrastructure is completed and delivered.

[0003] Currently, the production of high-precision maps generally relies on drone equipment to conduct a large amount of field data collection, and then perform complex internal processing of the field collected data. The map production cycle is long and the data processing workload is large. It is a typical reverse map collection and modeling technology. Its characteristic is that map collection and production need to be carried out after the construction of the park infrastructure is completed, which cannot meet the requirements of the synchronous development of the digital operation and maintenance platform and high-precision maps.

[0004] In view of this, there is an urgent need to design a forward-looking method for producing three-dimensional high-precision maps of the park and accurately positioning and matching them, which can be used to produce high-precision maps before the park infrastructure is completed and delivered, and to facilitate the synchronous development of the digital operation and maintenance park management platform. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of existing reverse mapping technology in meeting the needs of digital park projects, and to provide a forward production method for a three-dimensional high-precision map of a park based on BIM technology.

[0006] To achieve the above object, the technical solution of the embodiment of the present invention is implemented as follows:

[0007] A method for making a three-dimensional high-precision map of a park based on BIM technology includes the following steps:

[0008] S1, design the park BIM model and mark the feature points on the park BIM model;

[0009] S2, creating the current local rectangular coordinate system of the park, and recording the coordinates of the feature points in the local rectangular coordinate system;

[0010] S3, convert the 3D data format of the park BIM model and perform model material mapping;

[0011] S4, on-site marking of feature points in the park based on the construction coordinate system, and on-site measurement of the marked points based on the WGS84 ellipsoid coordinate system;

[0012] S5, based on the local plane rectangular coordinates of the feature points and the WGS84 ellipsoid coordinate system, the measured coordinates in S4 are transformed by Gauss projection;

[0013] S6, according to the coordinate values ​​of the projection transformation in S5 and the coordinate values ​​measured in S4, the translation parameters of the local plane rectangular coordinate system are calculated, and then the conversion equation between the WGS84 ellipsoid coordinate system and the local plane rectangular coordinate system is determined;

[0014] S7, importing the park BIM model processed in S3 into the graphics rendering platform and establishing a local coordinate system, using the conversion equation in S6 to convert the coordinate data measured on site in real time to generate a three-dimensional high-precision map;

[0015] S8, performs elevation calibration and alignment of positioning and maps.

[0016] Furthermore, the number of feature points selected in S1 is not less than 2.

[0017] Furthermore, the origin of the plane rectangular coordinate system in S2 is one of several characteristic points, and the park area falls within the first quadrant of the coordinate system in S2.

[0018] Furthermore, S2 also includes encrypting the local coordinate system. The encryption of the local coordinate system is specifically to rotate the local coordinate system along the origin by an angle, and use positive and negative values ​​to represent the rotation direction.

[0019] Furthermore, the model material map in S3 is selected for the beautified park buildings, roads, and landscape facilities, and the model material map is used to simulate the actual overall appearance of the park.

[0020] Furthermore, the Gaussian projection transformation in S5 adopts a 3-degree zone, and the longitude of the projection meridian is determined by the location of the park area.

[0021] Furthermore, S5 first determines the ellipsoid parameters of the WGS84 ellipsoid coordinate system, and then performs Gauss projection calculation.

[0022] Furthermore, the origin and coordinate axes of the local coordinate system in S7 are determined by the coordinates of the known feature points.

[0023] The beneficial effects of the present invention are:

[0024] The present invention firstly adopts Civil 3D and Revit to perform BIM design on the roads and buildings in the park; secondly, establishes a local coordinate system of the park plane, selects two or more feature points and determines the local coordinates of the feature points to determine the translation parameters of the local coordinate system after Gaussian projection transformation; thirdly, converts the format of the BIM model as a whole, imports it into 3Dmax for material mapping, and then packages it as a whole, and then imports it into the graphics rendering platform Unity3D to complete the static three-dimensional high-precision map; in addition, synchronously marks the feature points on site, records the coordinate values ​​in the WGS84 ellipsoid coordinate system, determines the meridian of this Gaussian projection transformation according to the area where the park is located, and establishes a Gaussian projection forward calculation model; finally, calculates the plane translation parameters according to the local coordinate values ​​of the feature points and the ellipsoid coordinate values, and then determines the conversion equation between the ellipsoid coordinate system and the local coordinate system, so as to realize the plane matching of the positioning data and the three-dimensional high-precision map;

[0025] By adopting the above steps, the accuracy of three-dimensional positioning and three-dimensional high-precision map registration can reach ±5cm, with good effect; the map and positioning matching method in a plane rectangular coordinate system based on BIM technology provided by the present invention is suitable for the forward production of three-dimensional high-precision maps before the construction of the park is completed, and can be used as a park-level high-precision map and digital twin project. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A technical roadmap for a method for producing a three-dimensional high-precision map of a park based on BIM technology in Example 1 of the present invention;

[0027] Figure 2 The Gaussian projection zone map involved in step 8 of a method for producing a three-dimensional high-precision map of a park based on BIM technology in Example 1 of the present invention;

[0028] Figure 3 This is a picture of the field measurement effect of the park during the verification process in Example 2 of the present invention;

[0029] Figure 4 This is a BIM modeling rendering of the verification process in Example 2 of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, the expression "some embodiments" is related to a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0031] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "inside", "outside", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0032] Example 1

[0033] Refer to the attached Figure 1-2 The present invention provides a method for making a three-dimensional high-precision map of a park based on BIM technology, comprising the following steps:

[0034] Step 1: BIMization of the Park

[0035] Civil 3D and Revit design modeling software are used to carry out BIM design of the park in the national WGS84 coordinate system (other coordinate systems can also be used here), describing the general process of digitization.

[0036] Step 2: Feature point selection

[0037] Select appropriate feature points on the BIM model as the basis for determining the local coordinate system after Gaussian projection transformation. Feature point selection should be easy to repeat, easy to mark, and evenly arranged. The number of feature points should be no less than 2, and multiple feature points can be selected to increase the accuracy of coordinate conversion. In principle, the more feature points, the higher the accuracy of coordinate conversion.

[0038] Step 3: Establishment of the local plane coordinate system of the park

[0039] Establish the local coordinate system "x`oy`" of the park and determine the origin "o" of the park coordinate. It is recommended to select a feature point in the BIM model as the origin. Principles for establishing the local coordinate system: (1) The scope of the park falls within the first quadrant of the local coordinate system, ensuring that the horizontal and vertical coordinates are both positive values; (2) To further encrypt the local coordinate system, the local coordinate system can be rotated by an angle θ, where counterclockwise is positive and clockwise is negative.

[0040] Step 4: Determine the coordinate values ​​of feature points

[0041] According to the established local coordinate system, calculate the local coordinate values ​​of the feature points (x`1, y`1), (x`2, y`2), ... (x`i, y`i). In principle, the more feature points there are, the higher the accuracy of the map that can be verified.

[0042] Step 5: Format conversion

[0043] Convert original BIM data into 3D model formats recognizable by Unity3D, such as FBX, OBG, etc.

[0044] Step 6: Model material selection

[0045] Model materials are selected based on the buildings, roads, and landscape facilities in the park to be built, and scene art processing is performed to simulate the overall appearance of the actual park as much as possible.

[0046] Step 7: Latitude and longitude coordinates of the selected feature points in the field measured model

[0047] Confirm the selected feature points on site and use high-precision positioning equipment to measure the corresponding longitude and latitude coordinates (B1, L1), (B2, L2)...(Bi, Li), where L is longitude and B is latitude.

[0048] Step 8: Determine the meridian of the area where the park is located

[0049] In order to improve the accuracy of projection transformation, the Gauss projection 3-degree zone is used. There are 22 3-degree zones (24 to 45 zones) within the borders of China. According to the location of the park, its projection meridian longitude L0 is determined (see attached Figure 2 Gaussian projection zonation diagram shown).

[0050] Step 9: Perform Gaussian projection transformation on the measured feature point accuracy coordinates, which mainly includes the following steps

[0051] (1) Determine the ellipsoid parameters. Different coordinate systems correspond to different ellipsoids.

[0052] spherical major axis a; spherical flattening f; ellipsoidal minor axis: b = a (1-f); ellipsoidal first eccentricity Second eccentricity of ellipsoid

[0053] (2) Gaussian projection calculation

[0054]

[0055] Where: x is the X-axis coordinate value in the plane coordinate system, y is the Y-axis coordinate value in the plane coordinate system, B is the latitude, L is the longitude, L0 is the meridian longitude, l``=L-L0; N is the meridian curvature radius, N=a(1-e 2 sin 2 B) -1 / 2 ; t = tanB; η 2 =e` 2 cos 2 B;ρ``=180 / π*3600.

[0056] Where X is the meridian arc length, calculated as follows:

[0057]

[0058] a0, a2, a4, a6, a8 are basic constants, calculated as follows:

[0059] a0=m0+m2 / 2+3 / 8*m4+5 / 16*m6+35 / 128*m8;

[0060] a2=m2 / 2+m4 / 2+15 / 32*m6+7 / 16*m8;

[0061] a4=m4 / 8+3 / 16*m6+7 / 32*m8;

[0062] a6=m6 / 32+m8 / 16;

[0063] a6=m8 / 128;

[0064] m0, m2, m4, m6, m8 are basic constants, calculated as follows:

[0065] m0=a(1-e 2 ); m2 = 3 / 2*e 2 m0;m4=5e 2 m2;m6=7 / 6e 2 m4;m8=9 / 8e 2 m6

[0066] The above calculation process can be used to calculate the plane rectangular coordinates (x, y) after the Gaussian projection change. The origin of the coordinates is the intersection of the meridian and the equator, the north direction along the meridian is the Y axis, and the east direction along the equator is the X axis.

[0067] Step 10: Determine the local coordinate system translation parameters

[0068] According to the method of step nine, the feature points measured on site are transformed into plane projection, and (B1, L1), (B2, L2)...(Bi, Li) are converted into (x1, y1), (x2, y2)...(xi, yi) in sequence.

[0069] Define the first feature point (x1, y1) as the origin of the local coordinate system after translation and rotation, and the remaining feature points are used to calibrate the positioning accuracy after translation. Then the new coordinate system "x`o`y`" can be determined according to the translation parameters u=-x1, v=-y1 and the rotation parameter θ. The conversion calculation formula is as follows:

[0070] x`=xcosθ+ysinθ+u

[0071] y`=-xsinθ+ycosθ+v

[0072] Where (x, y) is the coordinate point in the xoy plane rectangular coordinate system after Gaussian projection transformation, (x`, y`) is the coordinate point in the x`o`y` plane rectangular coordinate system after encryption, and the encryption parameters are u, v, and θ respectively.

[0073] At this time, (x2, y2)…(xi, yi) can be substituted into the conversion formula to obtain (x`2, y`2)…(x`i, y`i), and the conversion accuracy can be verified using BIM software.

[0074] Step 11: Use a computer program to convert the original longitude and latitude of the high-precision positioning device into local coordinate system coordinates

[0075] The original longitude and latitude are projected and transformed, and the coordinates are translated and rotated using a computer program language. The conversion process is as follows:

[0076] Latitude and longitude (B, L) → plane coordinates after Gaussian projection (xoy) → encrypted local coordinates (x`o`y`).

[0077] Later, Unity3D only needs to receive the processed coordinate values ​​to locate the target.

[0078] Step 12: Import the processed park BIM model into Unity3D and establish a local coordinate system to generate a three-dimensional high-precision map

[0079] Import the BIM model into Unity3D, and determine the coordinate origin o and the x`axis and y`axis based on the known feature point coordinates (x`1, y`1), (x`2, y`2), ... (x`i, y`i), and determine the coordinate system "x`oy`" under the Unity3D park project.

[0080] Move and rotate the BIM model with reference to the feature points so that the positions of the feature points match (x`1, y`1), (x`2, y`2), … (x`i, y`i).

[0081] Step 13: Elevation Calibration

[0082] Taking the lowest point of the park BIM model as ±0, the geodetic elevation d of the modified point is measured on site, and the elevation values ​​of the remaining points are h = Hd. Among them, d is the geodetic elevation value of the lowest point, h is the elevation value of any point in Unity3D, and H is the geodetic elevation value of any point.

[0083] Step 14: High-precision positioning and high-precision map registration

[0084] On-site handheld high-precision positioning equipment performs dynamic measurement at characteristic locations on site, and transmits the converted three-dimensional high-precision coordinate values ​​(x`, y`, h) in real time, and observes and measures the positioning map registration accuracy on a high-precision platform.

[0085] Example 2

[0086] Refer to the attached Figure 3-4 ,In order to verify this solution on site, the following steps are included:

[0087] Step 1: Taking the actual park as an example, the project location is Suizhou City, Hubei Province. Three characteristic points are determined on site, namely point 1: the center of the south ring, point 2: the corner of the north wall, and point 3: the center of the circular square (see attached). Figure 3 shown);

[0088] Step 2: Record the latitude and longitude coordinates of the three feature points: point 1 (113.5098508, 31.84472542), point 2 (113.51321759, 31.84497955), and point 3 (113.51424021, 31.86492475)

[0089] Step 3: Divide the projection into 3-degree zones. The project is located between 112.5° and 115.5° east longitude, and the central meridian is 114° east longitude. The WGS84 ellipsoid parameters are as follows:

[0090] Semi-major axis: a = 6378137 m

[0091] Flattening: f = 1 / 298.257223563

[0092] Step 4: Perform Gaussian projection transformation according to step 9 in Example 1 to obtain plane coordinates of point 1 (3524739.45, -46393.87), point 2 (3524766.19, -46075.07), and point 3 (3526977.40, -45968.38) in the Cartesian rectangular coordinate system.

[0093] Step 5: Determine the local coordinate system translation parameters. Taking point 1 as the origin of the local coordinate system, the translation parameters are u = -3524739.45, v = 46393.87.

[0094] Step 6: Determine the rotation parameter. For ease of understanding, the rotation parameter θ is set to 30°. This parameter can be set arbitrarily according to needs, and the range is (0°~180°).

[0095] Step 7: Get the encryption parameters - 3524739.45, 46393.87, 30°

[0096] Step 8: The encrypted coordinate output is:

[0097] x`=xcos30°+ysin30°-3524739.45

[0098] y`=-xsin30°+ycos30°+46393.87

[0099] Step 9: Taking the selected feature points as an example, the encrypted coordinates are point 1 (-495422.4796, -1756154.125), point 2 (-495239.9221, -1755891.406), and point 3 (-493271.613, -1756904.615)

[0100] Step 10: Carry out BIM modeling design according to the actual construction content of the park. The modeling effect is as shown in the attached Figure 4 shown.

[0101] Step 11: Import the BIM model into Unity3D and establish a local coordinate system, with point 1 as the origin, and then rotate 30° counterclockwise around the origin.

[0102] Step 12: On-site height calibration. Find the lowest point of the model relative to the center of the dynamic circular square. Assume that the lowest point of the model is the center of the dynamic circular square. The actual measured elevation is 112.5m. The height values ​​of the remaining points are H = h + 112.5.

[0103] Step 13: On-site accuracy verification. It was found that the horizontal accuracy error was within 10 cm and the vertical error was within 20 cm, meeting the requirements of the park's three-dimensional high-precision map production and positioning precision matching.

[0104] Field Calibration Points Data Sheet

[0105]

[0106] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for making a three-dimensional high-precision map of a park based on BIM technology, characterized in that: The steps include: S1, design the park BIM model and mark the feature points on the park BIM model; S2, create the current local rectangular coordinate system "x`oy`" of the park, determine the origin of the park coordinate "o", rotate the local rectangular coordinate system by an angle "θ", and record the coordinates of the feature points in the local rectangular coordinate system; S3, convert the 3D data format of the park BIM model and perform model material mapping; S4, on-site marking of feature points in the park based on the construction coordinate system, and on-site measurement of the marked points based on the WGS84 ellipsoid coordinate system; S5, based on the local plane rectangular coordinates of the feature points and the WGS84 ellipsoid coordinate system, the measured coordinates in S4 are transformed by Gauss projection; Among them, the steps of Gaussian projection transformation are: (1) Determine the ellipsoid parameters. Different coordinate systems correspond to different ellipsoids. spherical major axis a; spherical flattening f; ellipsoidal minor axis: b = a (1-f); ellipsoidal first eccentricity Second eccentricity of ellipsoid (2) Gaussian projection calculation Where: x is the X-axis coordinate value in the plane coordinate system, y is the Y-axis coordinate value in the plane coordinate system, B is the latitude, L is the longitude, L0 is the meridian longitude, l``=L-L0; N is the meridian curvature radius, N=a(1-e 2 sin 2 B) -1 / 2 ; t = tanB; η 2 =e` 2 cos 2 B;ρ``=180 / π*3600; Where X is the meridian arc length, calculated as follows: a0, a2, a4, a6, a8 are basic constants, calculated as follows: a0=m0+m2 / 2+3 / 8*m4+5 / 16*m6+35 / 128*m8; a2=m2 / 2+m4 / 2+15 / 32*m6+7 / 16*m8; a4=m4 / 8+3 / 16*m6+7 / 32*m8; a6=m6 / 32+m8 / 16; a6=m8 / 128; m0, m2, m4, m6, m8 are basic constants, calculated as follows: m0=a(1-e 2 );m2=3 / 2*e 2 m0;m4=5e 2 m2;m6=7 / 6e 2 m4;m8=9 / 8e 2 m6; S6, according to the coordinate values ​​of the projection transformation in S5 and the coordinate values ​​measured in S4, the translation parameters u and v of the local plane rectangular coordinate system are calculated, and the new coordinate system "x`o`y`" is determined according to the translation parameters and the rotation parameter θ, and the conversion equation is as follows: x`=xcosθ+ysinθ+u y`=-xsinθ+ycosθ+v Where (x, y) is the coordinate point in the xoy plane rectangular coordinate system after Gaussian projection transformation, (x`, y`) is the coordinate point in the x`o`y` plane rectangular coordinate system after encryption, and the encryption parameters are u, v and θ respectively; S7, importing the park BIM model processed in S3 into the graphics rendering platform and establishing a local coordinate system, using the conversion equation in S6 to convert the coordinate data measured on site in real time to generate a three-dimensional high-precision map; S8, performs elevation calibration and alignment of positioning and maps.

2. The method for making a three-dimensional high-precision map of a park based on BIM technology according to claim 1 is characterized in that: The number of feature points selected in S1 is no less than 2.

3. The method for making a three-dimensional high-precision map of a park based on BIM technology according to claim 1 is characterized in that: The origin of the plane rectangular coordinate system in S2 is one of several characteristic points, and the park range falls in the first quadrant of the coordinate system in S2.

4. The method for making a three-dimensional high-precision map of a park based on BIM technology according to claim 1 is characterized in that: The S2 also includes encrypting the local coordinate system. The encryption of the local coordinate system is specifically to rotate the local coordinate system along the origin by an angle, and use positive and negative values ​​to represent the rotation direction.

5. The method for making a three-dimensional high-precision map of a park based on BIM technology according to claim 1 is characterized in that: The model material map selected in S3 is the beautified park buildings, roads, and landscape facilities, and the model material map is used to simulate the actual overall appearance of the park.

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