Village and town building planning and designing method and system based on surveying and mapping modeling

Abstract

The invention discloses a town building planning and designing method and system based on surveying and mapping modeling, and the method comprises the steps: obtaining vector data, a digital elevation model and a digital orthoimage of a planning region, and carrying out the coordinate projection and attribute information preprocessing; performing batch three-dimensional modeling on the vector data by using a CityEngine platform and a CGA rule file to generate a planning three-dimensional model including roads, buildings and greening facilities, and realizing detail iteration through a cascade rule; the planning three-dimensional model and the live-action three-dimensional oblique photography model are fused, and seamless splicing of the models is ensured through local terrain leveling processing and elevation adjustment; performing sunshine analysis based on the fused three-dimensional scene, calculating a solar altitude angle, a solar azimuth angle and a time angle, simulating sunshine time and a shadow area, and optimizing the building layout; and finally, through a three-dimensional line-of-sight analysis algorithm, assessing intervisibility conditions and view fields of the key nodes, generating a view field body model, and adjusting the building layout and density.

Description

Technical Field

[0001] The present invention relates to the field of planning and design technology, and more specifically, to a method and system for planning and designing village and town buildings based on surveying and mapping modeling. Background Art

[0002] Traditional two-dimensional planning methods (such as CAD drawings) have obvious deficiencies in expressing spatial relationships, terrain adaptation, and visualization effects, making it difficult to meet the scientific, accurate, and intuitive requirements of modern village and town planning. Especially in complex terrain areas (such as mountains and hills), two-dimensional drawings cannot fully reflect the spatial relationship between buildings and terrain, resulting in problems such as excessively high site leveling costs, insufficient building lighting, and obstructed views during the implementation phase of the planning scheme. In addition, village and town planning involves multiple stakeholders, including the government, villagers, and construction units. Traditional two-dimensional expressions are difficult for non-professionals to understand, affecting public participation and decision-making efficiency. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a village and town building planning and design method and system based on surveying and mapping modeling to solve at least one of the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: In step S1, basic surveying and mapping data of the planning area are obtained, including high-precision vector data, digital elevation models and digital orthophotos; vector data are extracted through national land space planning results or on-site surveying and mapping, including village boundaries, road networks, building bases, and land use types; digital elevation models are generated through airborne LiDAR acquisition, which can accurately reflect the terrain undulation characteristics and provide an elevation benchmark for three-dimensional terrain modeling; and digital orthophotos are obtained through satellite remote sensing, with real texture information, which can be used as scene maps or planning base maps; after the data is acquired, the coordinate projection is converted so that all data are in the same spatial reference system, such as converting Gaussian plane coordinates to WGS84 or CGCS2000 coordinate systems to avoid coordinate deviations in the subsequent modeling process.

[0005] Preferably, in step S2, the pre-processed data is imported into the CityEngine workspace, and CGA rule files are compiled for different types of planning elements. For building modeling, the rule file usually uses fields such as "building height" and "roof type" in the plot attribute table as parameters, and uses the extrude function to stretch the building base surface in the vertical direction to form a white mold. Then, the comp(f) function is combined to segment the facade, roof and other components, and the texture function is called to bind texture maps to different material surfaces. Road modeling is based on centerline data, with the split(v) function used to layer the roadbed and sidewalks. The FitWidth to Shape function is used to dynamically adapt the road width to the boundaries of the surrounding plots. At the same time, the PlacementPoint rule is used to automatically arrange street trees or streetlight models at intervals on both sides of the road. Green facility modeling combines GIS land use attributes, using split(u) to divide the park area into functional zones, implanting sports facility OBJ models in the leisure and sports area, and batch instantiating tree species models in the vegetation area through the i() function. The grounding position of the trees is adjusted according to the DEM elevation.

[0006] Preferably, in step S3, the two models are converted to the same coordinate system using the CGCS2000 national geodetic coordinate system through spatial coordinate conversion; for the real-scene three-dimensional model, the terrain matching problem in the planning area is processed: the OSGB format model generated by oblique photography is locally leveled using a professional three-dimensional editing tool, and the elevation values of the leveled area are intelligently interpolated by traversing the triangulated network vertex array using the Kriging interpolation algorithm to form a naturally transitioned flat terrain surface, eliminating the influence of the original terrain undulations on the planned building location; at the same time, according to the site leveling elevation determined in the planning and design plan, a leveling range surface with a Z value is created in ArcGIS Pro as a benchmark reference for terrain processing.

[0007] Preferably, in step S4, sunshine analysis is performed, including calculating the solar altitude angle, solar azimuth angle and sunrise and sunset times according to the geographic coordinates; the calculation method of the solar altitude angle is specifically as follows: Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle, h is expressed as hour angle; The solar altitude is the angle between the line between the sun and the observation point on the earth and the horizon; The calculation method of the solar azimuth angle is as follows: A represents the solar azimuth angle, which is 0 degrees at 12 o'clock. Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle; The solar azimuth is the angle between the sun's direct projection onto the horizon and the south line of the horizon. When the sun is due south, the solar azimuth is 0. When the sun is due south, the azimuth is positive. When the sun is due south, the azimuth is negative.

[0008] Preferably, in step S5, a topological relationship is established for a complete three-dimensional scene including terrain, buildings, and vegetation, and a hierarchical bounding box acceleration structure is used to optimize the efficiency of ray intersection calculations. For key nodes, evenly distributed test rays are emitted from the observer's viewpoint in all directions, with the ray density set to 1 degree intervals horizontally and covering an elevation range of -15° to 45° vertically. The intersection of each ray with the scene model uses the Möller-Trumbore algorithm to quickly determine the intersection with the triangle facets. When an intersection is detected, it is marked as a line of sight obstruction point.

[0009] Technical effects and advantages of the present invention: The present invention generates high-precision planning scenarios through CityEngine modeling, and realizes multi-source data fusion by combining terrain leveling and elevation matching technology of oblique photography model; establishes a sunshine analysis model based on sun trajectory calculation, adopts spherical-conical surface intersection algorithm to accurately calculate building sunshine spacing and shadow range, and combines line-of-sight ray detection and viewshed volume analysis to evaluate the visual conditions of key nodes; improves computing efficiency through spatial index optimization and ray tracing acceleration technology, generates a three-dimensional evaluation system including sunshine duration, shadow distribution and visibility probability, and provides quantitative optimization suggestions for building height, layout density and sight corridor for planning schemes; the present invention improves modeling efficiency by combining the characteristics of villages and towns with regularized modeling, solves model fusion problems through high-precision coordinate transformation, and integrates algorithms such as three-dimensional sight line analysis and sunshine simulation to provide quantitative basis for the scientificity and rationality of planning schemes; the final system should have the ability of multi-source data integration, interactive design optimization and visual decision support. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the method of the present invention.

[0011] Figure 2 Schematic diagram of module connection of the present invention. DETAILED DESCRIPTION

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 efforts are within the scope of protection of the present invention.

[0013] See also Figure 1 As shown, the present invention provides a village and town building planning and design method based on surveying and mapping modeling, comprising: S1: Obtain vector data, digital elevation model and digital orthophoto of the planning area, and perform coordinate projection and attribute information preprocessing; In step S1, basic surveying and mapping data of the planning area are obtained, including high-precision vector data, digital elevation models and digital orthophotos; vector data are extracted through national land space planning results or on-site surveying and mapping, including village boundaries, road networks, building bases, and land use types; digital elevation models are generated through airborne LiDAR acquisition, which can accurately reflect the terrain undulation characteristics and provide an elevation benchmark for three-dimensional terrain modeling; and digital orthophotos are obtained through satellite remote sensing, with real texture information, which can be used as scene maps or planning base maps; after the data is acquired, the coordinate projection is converted so that all data are in the same spatial reference system, such as converting Gaussian plane coordinates to WGS84 or CGCS2000 coordinate systems to avoid coordinate deviations in the subsequent modeling process.

[0014] In step S1, during the data preprocessing stage, the coordinate system of multi-source data is normalized. At the same time, the vector attribute fields need to be standardized, including the addition of building height, land use nature, and road grade parameters to provide attribute support for CGA rule-driven modeling.

[0015] For terrain data, outliers in DEM are eliminated through cut-fill analysis, and image registration technology is used to ensure spatial alignment between DOM and vector data, ultimately forming a standardized dataset with unified coordinates, complete attributes, and standardized topology.

[0016] S2: Based on the CityEngine platform, batch 3D modeling is performed on the pre-processed data using CGA rule files to generate a planned 3D model including roads, buildings, and green facilities; In step S2, the preprocessed data is imported into the CityEngine workspace, and CGA rule files are compiled for different types of planning elements. For building modeling, the rule file usually uses fields such as "building height" and "roof type" in the plot attribute table as parameters. The extrude function is used to stretch the building base surface in the vertical direction to form a white mold. The comp(f) function is then used to segment the facade, roof and other components, and the texture function is called to bind texture maps to different material surfaces.

[0017] Taking the modeling of typical farmhouses in rural Chongqing as an example, a roofGable function was specifically added to the rule file to generate sloping roofs with local characteristics. By setting random parameters, the roof's inclination angle naturally varies between 20° and 45°. This not only conforms to the actual characteristics of local buildings, but also prevents the model from being too rigid, greatly enhancing the naturalness and diversity of the scene.

[0018] Road modeling is based on centerline data, with the split(v) function used to layer the roadbed and sidewalks. The FitWidth to Shape function is used to dynamically adapt the road width to the boundaries of the surrounding plots. At the same time, the PlacementPoint rule is used to automatically arrange street trees or streetlight models at intervals on both sides of the road. Green facility modeling combines GIS land use attributes, using split(u) to divide the park area into functional zones, implanting sports facility OBJ models in the leisure and sports area, and batch instantiating tree species models in the vegetation area through the i() function. The grounding position of the trees is adjusted according to the DEM elevation.

[0019] The entire modeling process implements detail iteration through the cascading rule chain of house→facade→window→balcony, ultimately generating an overall scene model that integrates terrain, retains CAD / GIS attributes, and supports 3D analysis with just one click.

[0020] S3: Fusing the planned 3D model with the real-scene 3D oblique photography model, including leveling the local terrain of the real-scene 3D model and adjusting the bottom elevation of the planned 3D model to match the terrain; In step S3, the two models are converted to the same coordinate system using the CGCS2000 national geodetic coordinate system through spatial coordinate conversion; for the real-life 3D model, the terrain matching problem in the planning area is processed: the OSGB format model generated by oblique photography is locally leveled using professional 3D editing tools, and the elevation values of the leveled area are intelligently interpolated by traversing the triangulated network vertex array using the Kriging interpolation algorithm to form a naturally transitioned flat terrain surface, eliminating the impact of the original terrain undulations on the planned building location; at the same time, according to the site leveling elevation determined in the planning and design plan, a leveling range surface with a Z value is created in ArcGIS Pro as a benchmark reference for terrain processing.

[0021] For the planned three-dimensional model, the building base elevation is adjusted using the strategy of "overall elevation + local fine-tuning". The site design elevation is calculated based on the leveled DEM data, and then the Elevation parameters in the CGA rules are modified in batches through Python scripts. A dual elevation benchmark is established for underground space processing. The above-ground part adopts the elevation system after leveling, and the underground part maintains the relative elevation. For special structures such as sunken squares, a 2-meter-wide transition zone is set around it, and the smooth function is used to achieve elevation gradient. All adjusted models must pass a topological check to ensure that the gap between the building bottom surface and the terrain surface does not exceed 3 centimeters. In the model fusion stage, LOD technology is used to optimize display efficiency, a fine model is used for the center of the planning area, and the edge area is appropriately simplified. At the same time, a spatial index mechanism is established to achieve dynamic loading and seamless splicing of the two models.

[0022] S4: Perform sunshine analysis based on the fused 3D scene; In step S4, sunshine analysis is performed, including calculating the solar altitude angle, solar azimuth angle, and sunrise and sunset times according to the geographic coordinates. The specific method for calculating the solar altitude angle is: Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle, h is expressed as hour angle; The solar altitude is the angle between the line between the sun and the observation point on the earth and the horizon; The calculation method of hour angle is as follows: h represents the hour angle, S represents the local true solar time; The solar hour angle refers to the angular distance from the celestial meridian of the observation point along the celestial equator to the hour circle where the sun is located; The calculation method of declination angle is as follows: d is the declination angle, Expressed as day angle; Declination is the angle between the line connecting the sun and the center of the earth and the equatorial plane; The calculation method of the solar azimuth angle is as follows: A represents the solar azimuth angle, which is 0 degrees at 12 o'clock. Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle; The solar azimuth refers to the angle between the projection line of sunlight directly on the horizon and the south line of the horizon. When the sun is in the south, the solar azimuth is 0, when the sun is in the southwest, the azimuth is positive, and when the sun is in the southeast, the azimuth is negative. The specific method for calculating sunrise time is: Represents the sunrise time, Expressed as the sunrise solar hour angle; The specific method for calculating sunset time is: Indicates sunset time The solar altitude angle at sunrise and sunset is 0; The calculation method of sunrise solar hour angle is as follows: It is expressed as the sunrise solar hour angle, is expressed as the local latitude, It is expressed as declination angle; The calculation method of sunset solar hour angle is as follows: It is expressed as the sunset solar hour angle, Expressed as the sunrise solar hour angle.

[0023] Factors influencing the solar altitude angle include true solar time, declination, and hour angle. True solar time is defined as 12:00 when the sun is due south at the local time. Because true solar time varies at different longitudes, countries adopt one or more time zones as the unified standard time for each country or region to facilitate daily life. my country adopts true solar time at 120 degrees east longitude as the national unified standard time (i.e., GMT+8). The relationship between true solar time and Beijing time is as follows: The above formula ignores the time of day throughout the year. Where N is the local true solar time, is standard time, is the standard time position longitude, is the local longitude. When the local location is west of the standard time position, ± is negative; when the local location is east of the standard time position, ± is positive.

[0024] Sunshine duration analysis simulates the sun's trajectory and determines whether the observation point is directly illuminated by the sun based on the line of sight between the observation point and the sun's position, thereby calculating the sunshine duration. The sunshine conic surface calculates sunshine duration primarily by describing the sun's trajectory in space throughout the day. Rays are connected to the observation point according to the sun's position at each time, resulting in a ray-connected surface. The surface equation is derived from the formulas for the solar altitude and azimuth angles. The surface divides the celestial sphere into spherical cones to form a spherical conical surface. By finding the intersection of this spherical conical surface with the spatial building model, a complete sunshine analysis diagram is obtained. By determining the time points of the intersection line between the surface and the spatial building model, the time intervals of obstruction and illumination are determined, allowing the sunshine duration to be calculated.

[0025] Sunlight shadow area analysis uses a ray intersection shadow analysis algorithm to calculate the sun's spatial position at various times of the day, thereby simulating the sun's daily trajectory. Because the sun is extremely far from the Earth, its rays can be approximated as parallel rays. By simulating sunlight from the sun's direction, the intersection points between the rays and terrain are determined, and the rays are divided into two sets. Rays that intersect with buildings are placed in set M, resulting in set M = {M1, M2, M3…Mn}. Rays that do not intersect with buildings are placed in set N, resulting in set N = {N1, N2, N3…Nn}. The intersection points of the rays in set M with terrain and features are calculated, and the distribution range of the rays in set M is calculated based on these intersection points. Since all rays in set M intersect with buildings, the distribution range of the intersection points between the rays and terrain and features in set M is the shadow.

[0026] The specific steps for determining the shadow range are: Determine whether the sun's rays intersect the building; intersecting rays are stored in set M, and non-intersecting rays are stored in set N. Obtain tile data from set M where the rays intersect. Triangulate each grid of the tile data and traverse each grid one by one. Further determine whether the triangulated mesh intersects the ray. If so, calculate the intersection coordinates and save the triangles in array D, resulting in D = {D1, D2, D3…Dn}. Traverse all triangles in all tiles according to the above rules. Draw and render the triangles in the array to determine the shadow range, and calculate the area of the triangles in array D.

[0027] Sunshine spacing coefficient when the building is facing south or south-east (west) The specific calculation method is: It represents the solar altitude angle, A represents the solar azimuth angle, and t represents the current time. Expressed as solar hour angle; Sunshine spacing coefficient when the building is east or west facing The specific calculation method is: It is expressed as the solar altitude angle, and A is expressed as the solar azimuth angle; The calculation method of building spacing is as follows: D represents the distance between buildings, H represents the height of the building in front, Expressed as sunshine spacing coefficient; Building sunlight spacing refers to the horizontal distance between two buildings in front and behind, ensuring that buildings meet national regulations for guaranteed sunlight hours. Generally, building sunlight spacing refers to the distance between residential buildings, or the distance between facades. The sunlight spacing coefficient is the ratio of the nationally specified distance between buildings to the height of the obstructing eaves. The residential sunlight spacing coefficient is a key indicator for determining residential spacing.

[0028] S5: Based on the 3D line of sight analysis algorithm, evaluate the visibility conditions and field of view of key nodes in the planning area and adjust the building layout and density.

[0029] Key nodes include building rooftops, balconies, windows, and other locations. In step S5, based on a 3D line-of-sight analysis algorithm, the visibility and field of view of key nodes within the planning area are evaluated. Specifically, this involves establishing the topological relationship of a complete 3D scene encompassing terrain, buildings, and vegetation, and employing a hierarchical bounding box acceleration structure to optimize the efficiency of ray intersection calculations. For key nodes, evenly distributed test rays are emitted from the observer's viewpoint in all directions, with the ray density set to 1-degree intervals horizontally and covering an elevation range of -15° to 45° vertically. The intersection of each ray with the scene model uses the Möller-Trumbore algorithm to quickly determine if it intersects with a triangle. Any intersection detected is marked as a line-of-sight obstruction point.

[0030] To accurately simulate real-world viewing conditions, the algorithm also accounts for the curvature of the earth and atmospheric refraction corrections, compensating for the curvature of ray paths for long-distance observation (over 500 meters). The viewshed analysis results accumulate the spatial distribution of all visible rays to generate a three-dimensional viewshed model and calculate the visibility probability in all directions. For building layout optimization, the algorithm pays special attention to the following indicators: mutual visibility of important landscape nodes, such as sight corridors between landmark buildings; the openness of public spaces, requiring that more than 80% of the test rays be unobstructed; and the visual comfort of building spacing.

[0031] When implementing the algorithm, a three-dimensional R-tree spatial index is constructed to accelerate scene queries, and the DDA digital differential algorithm is used to traverse each line of sight, detecting the intersection with the building model and terrain triangulation in real time. When encountering an obstruction, the spatial coordinates and distance of the interruption point are recorded and marked as an invisible area. By aggregating the analysis results of all lines of sight, a comprehensive evaluation heat map is generated that includes indicators such as visibility probability, line of sight distance, and field of view width.

[0032] For the visual blind spots discovered through analysis, optimization suggestions are automatically given: lowering building height or adjusting building setbacks in areas with severe obstruction; recommending the establishment of viewing platforms or open spaces for nodes with limited vision; and proposing building height control requirements for important landscape corridors.

[0033] See also Figure 2As shown, in this embodiment, it should be specifically explained that the present invention provides a village and town building planning and design system based on surveying and mapping modeling, including: Data preprocessing module: used to obtain vector data, digital elevation models and digital orthophotos of the planning area, and perform coordinate projection and attribute information preprocessing; 3D modeling module: Based on the CityEngine platform, it uses CGA rule files to perform batch 3D modeling on pre-processed data to generate a planned 3D model including roads, buildings, and green facilities. Model fusion module: used to fuse the planning 3D model with the real-scene 3D oblique photography model, including leveling the local terrain of the real-scene 3D model and adjusting the bottom elevation of the planning 3D model to match the terrain; Sunlight analysis module: used to perform sunlight analysis based on the fused 3D scene; Evaluation and Optimization Module: Used to evaluate the visibility conditions and field of view of key nodes in the planning area based on a three-dimensional line of sight analysis algorithm, and adjust the building layout and density.

[0034] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The village and town building planning and design method based on surveying and mapping modeling is characterized by: include: S1: Obtain vector data, digital elevation model and digital orthophoto of the planning area, and perform coordinate projection and attribute information preprocessing; S2: Based on the CityEngine platform, batch 3D modeling is performed on the pre-processed data using CGA rule files to generate a planned 3D model including roads, buildings, and green facilities; S3: Fusing the planned 3D model with the real-scene 3D oblique photography model, including locally leveling the real-scene 3D model and adjusting the bottom elevation of the planned 3D model to match the terrain, to form a fused 3D scene. S4: Perform sunshine analysis based on the fused 3D scene; S5: Based on the 3D line of sight analysis algorithm, evaluate the visibility conditions and field of view of key nodes in the planning area and adjust the building layout and density.

2. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 1 is characterized by: In step S1, basic surveying and mapping data of the planning area are obtained, including vector data, digital elevation models, and digital orthophotos; the vector data includes village boundaries, road networks, building bases, and land use types; Digital elevation models are generated through airborne LiDAR data collection, which can reflect the terrain undulations and provide an elevation benchmark for 3D terrain modeling. Digital orthophotos are obtained through satellite remote sensing; after the data is acquired, the coordinate projection is converted so that all data are in the same spatial reference system.

3. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 1 is characterized by: In step S2, the preprocessed data is imported into the CityEngine workspace, and CGA rule files are compiled for different types of planning elements. For building modeling, the rule file uses the "Building Height" and "Roof Type" fields in the plot attribute table as parameters. The extrude function is used to stretch the building base vertically to form a blank model. The comp(f) function is then used to segment the facade and roof components, and the texture function is called to bind texture maps to different material surfaces.

4. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 1 is characterized by: In step S3, the two models are converted to the same coordinate system using the CGCS2000 national geodetic coordinate system through spatial coordinate conversion; For the real-life 3D model, the terrain matching problem within the planning area was addressed: 3D editing tools were used to locally level the OSGB format model generated by oblique photography. By traversing the triangulated vertex array, the Kriging interpolation algorithm was used to interpolate the elevation values of the leveled area to form a smooth terrain surface with a natural transition, eliminating the impact of the original terrain undulations on the planned building placement. At the same time, based on the site leveling elevation determined in the planning and design plan, a leveling range surface with a Z value was created in ArcGIS Pro as a benchmark reference for terrain processing.

5. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 1 is characterized in that: In step S4, sunshine analysis is performed, including calculating the solar altitude angle, solar azimuth angle, and sunrise and sunset times according to the geographic coordinates; The calculation method of the solar altitude angle is: Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle, h is expressed as hour angle; The hour angle is calculated as: h represents the hour angle and S represents the local true solar time.

6. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 5 is characterized by: The calculation method of the solar azimuth angle is: A represents the solar azimuth, Expressed as the solar altitude angle, is expressed as the local latitude, It is expressed as declination angle; The sunrise time is calculated as follows: Represents the sunrise time, Expressed as the sunrise solar hour angle; The specific method for calculating sunset time is: Indicates sunset time The solar altitude angle at sunrise and sunset is 0; The calculation method of sunrise solar hour angle is: It is expressed as the sunrise solar hour angle, is expressed as the local latitude, It is expressed as declination angle; The calculation method of sunset solar hour angle is as follows: It is expressed as the sunset solar hour angle, Expressed as the sunrise solar hour angle.

7. The method for planning and designing village and town buildings based on surveying and mapping modeling according to claim 1 is characterized by: In step S5, based on the three-dimensional line of sight analysis algorithm, the visibility conditions and field of view of key nodes in the planning area are evaluated, including: The topological relationship of the three-dimensional scene, including terrain, buildings, and vegetation, is established, and a hierarchical bounding box acceleration structure is used to optimize the efficiency of ray intersection calculations. For key nodes, evenly distributed test rays are emitted from the observer's viewpoint in all directions, with the ray density set to 1 degree intervals horizontally and covering an elevation angle range of -15° to 45° vertically. The intersection process of each ray with the scene model uses the Möller-Trumbore algorithm to quickly determine the intersection with the triangle facets. When an intersection is detected, it is marked as a line of sight blockage point.

8. A village and town building planning and design system based on surveying and mapping modeling, using the village and town building planning and design method based on surveying and mapping modeling as claimed in any one of claims 1 to 7, characterized in that: Data preprocessing module: used to obtain vector data, digital elevation models and digital orthophotos of the planning area, and perform coordinate projection and attribute information preprocessing; 3D modeling module: Based on the CityEngine platform, it uses CGA rule files to perform batch 3D modeling on pre-processed data to generate a planned 3D model including roads, buildings, and green facilities. Model fusion module: used to fuse the planning 3D model with the real-scene 3D oblique photography model, including leveling the local terrain of the real-scene 3D model and adjusting the bottom elevation of the planning 3D model to match the terrain; Sunlight analysis module: used to perform sunlight analysis based on the fused 3D scene; Evaluation and Optimization Module: Used to evaluate the visibility conditions and field of view of key nodes in the planning area based on a three-dimensional line of sight analysis algorithm, and adjust the building layout and density.

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