A method and system for processing scene characteristics data based on urban three-dimensional spatial form

Abstract

This invention discloses a method and system for digitizing the data of scene features based on the three-dimensional spatial morphology of cities. The system includes the following modules: an environment model construction module, which collects and constructs a database scene of the current three-dimensional spatial morphology of the city; a scene information extraction module, which acquires vector data of building outlines within the field of view and the scene frame at the viewpoint; a scene volume feature calculation module, which calculates the area of ​​buildings within the scene frame and the area of ​​other buildings in the field of view based on the vector data, thereby obtaining scene volume feature information; a scene height feature calculation module, which calculates scene height feature information by comparing the height and positional relationship between buildings within the scene frame and other buildings in the field of view; and a data output module, which quantifies and outputs the scene feature data. This invention overcomes the limitations of existing methods in viewpoint selection and possesses scientific rigor, universality, and repeatability, providing decision-making basis and scientific support for urban spatial layout control and optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of urban planning, and in particular to a method and system for digitally processing scene features based on the three-dimensional spatial form of a city. Background Art

[0002] The opposite scene serves as a special visual focus and perspective [1] , its essence is to construct a visual focus in the field of vision, which has a positive impact on the spatial level of visual perception and is a direct judgment of the complexity and richness of space. In the construction of high-quality urban space, the view is an important part of the city's important visual aesthetic landscape, which is mostly generated by the visual focus created by the axis organization in the field of vision. The characteristics of the view can objectively reflect the interaction between people and the view and the connection between the view and the view. It is also a direct feedback of the urban morphological spatial structure at the visual perception level. Therefore, the data processing of the view characteristics is an important part of the urban planning and construction department's evaluation and optimization of urban space. Using the results of the data processing of the view characteristics as an indicator is helpful for urban planning and design decisions, and can also serve as an important basis for the control and optimization of urban space layout.

[0003] Existing studies on landscape characteristics are mostly based on qualitative research in the context of gardens. [2] , mostly through observation, evaluation and analysis by taking photos and drawing [3][4] , these methods are guided by subjective qualitative evaluation, and lack scientificity, universality and repeatability because the observation points cannot be evenly distributed, the shooting parameters are uncertain, and a large amount of manual measurement is required. In addition, the qualitative analysis research based on a limited number of viewpoints has low accuracy, and it is difficult to fully digitize the characteristics of the scenery in an urban area, and it is impossible to provide accurate data support for urban space evaluation and optimization. The limitations of these methods mainly come from two reasons: First, in terms of data collection, relying solely on manual measurement to obtain data makes the viewpoint selection too subjective, and it is difficult to cover most of the effective viewpoints within the city; second, in terms of quantitative evaluation, there is a lack of accurate expression of complex space, and the evaluation is relatively subjective, and it is difficult to obtain quantitative and accurate conclusions, which greatly limits its scope of application.

[0004] Therefore, in the high-quality urban spatial planning that emphasizes people-oriented, the data processing method and system of the scenery characteristics based on the three-dimensional spatial form of the city is not only a difficult problem to be solved urgently in the academic community, but also an urgent need in the field of urban planning practice.

[0005] References:

[0006] [1]Cullen G.Concise Townscape[M].Boston:Architectural Press,1961.

[0007] [2] Han Lele. Research on the application of landscape theory in urban landscape design[D]. Jinan: Shandong Jianzhu University, 2018.

[0008] [3] Wang Mei. Spatial reciprocation and landscape design[D]. Tianjin: Tianjin University, 2018.

[0009] [4] Wei Baozhi. Research on the application of traditional landscaping techniques in modern gardens[D]. Fuzhou: Fujian Agriculture and Forestry University, 2011. Summary of the invention

[0010] Purpose of the invention: In view of the deficiencies of the above-mentioned prior art, the present invention provides a method and system for digital processing of scenery features based on urban three-dimensional spatial morphology. The method is based on the urban three-dimensional spatial morphology model and vector data, and through information representation of the real field of view of all valid viewpoints within a given urban area, the volume characteristics and height characteristics of the scenery of each viewpoint in the real-time scene are calculated respectively; thereby realizing the digital processing of scenery features within an urban area, providing decision-making basis and scientific support for urban spatial layout control and optimization.

[0011] Technical solution: The present invention provides a method and system for processing scene feature data based on the three-dimensional spatial form of a city, which specifically includes the following steps:

[0012] Step 1: Collect the basic information of the current three-dimensional spatial form of the city and establish a database scenario of the urban spatial form, as follows:

[0013] Step 1.1, collect basic urban geographic information data based on open source data information, build urban digital terrain model and urban building model polyhedron layer, import them into the geographic information system software ArcGIS, and unify the coordinate system of each layer;

[0014] Step 1.2, rasterize the entire surface of the observation area set in the urban digital terrain model, select the geometric center point of each grid as the viewpoint representing the grid, and create a three-dimensional point feature to form a continuous three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}; where lon i ,lat i represents the coordinate value of the i-th viewpoint, h i is the viewpoint height, and N is the number of viewpoints.

[0015] Step 1.3, for the three-dimensional viewpoint set OP{(lon i ,lat i ,h i),i∈N}, the viewpoint P determines the field of view of the viewpoint P according to the line of sight direction SD [AZ l ,AZ u ], the method is as follows,

[0016] AZ l =SD-L view / 2, AZ u =SD+L view / 2, of which AZ l Indicates the lower boundary of the field of view, AZ u Indicates the upper boundary of the field of view, L view The width of the field of view is usually considered to be 120°.

[0017] Step 2: Get the vector data of the building outline in the field of view and extract the scene information, as follows:

[0018] Step 2.1, for viewpoint P, generate vector data of azimuth angle X and vertical angle Y from viewpoint P to each vertex in the contour line element through the Skyline and Skyline Graph tools in ArcGIS;

[0019] Step 2.2, according to the field of view [AZ l ,AZ u ] extracts the building outline information within the field of view at the viewpoint and forms a vector data set D{(x i ,y i )}, with the azimuth as the horizontal axis and the vertical angle as the vertical axis, the outline of the building in the field of view is generated in the two-dimensional field of view;

[0020] Step 2.3, determine the scope of the scene frame according to the golden ratio. Set the spatial range of the horizontal coordinate of the field of view range 38.2% to 61.8% as the scene frame area [OF l ,OF u ]. The upper and lower boundaries of the frame l ,OF u OF is obtained by the following formula l =AZ l +(AZ u -AZ l )*0.382,OF u =AZ l +(AZ u -AZ l )*0.618;

[0021] Step 2.4, further extract the vector dataset D{(x i ,y i )} in the view frame area, forming the view building outline vector dataset Do{(x′j ,y′ j )}. If the data set is empty, This means that there is no background building in the background frame, and the result of the data processing of the background feature is 0.

[0022] Step 3: Data processing of the volume characteristics of the scene. The volume characteristics Vs of the scene reflect the relative prominence of the building volume in the scene frame in the field of vision. The specific method is to calculate the building area S in the scene frame. O The building area S in the field of view B The ratio is as follows:

[0023] V S =S O / S B ;

[0024] The building area S in the field of view is obtained by the following formula B ,

[0025]

[0026] where x i ,y i Represents the building outline information vector dataset D{(x i ,y i )}. The building area in the field of view is represented by the adjacent points (x i ,y i ), (x i+1 ,y i+1 ) and the X-axis to form the sum of the areas of the trapezoids. The building area S in the scene frame is obtained by the following formula O ,

[0027]

[0028] where x′ j ,y′ j Represents the building outline vector dataset Do{(x′ j ,y′ j )}. The building area in the scene frame is represented by the adjacent point (x′ j ,y′ j ), (x′ j+1 ,y′ j+1 ) is the sum of the areas of the trapezoids formed by the X-axis.

[0029] Step 4: Data processing of the scene height feature. The height feature reflects the relative prominence of the building height in the scene frame in the field of vision. Based on the building outline information in the scene frame, if there is a building with the highest point in the entire field of vision in the scene frame, the scene height feature V hThe data processing is as follows:

[0030] V h =(H OF -H SS ) / L view ,

[0031] Among them, H OF =max{y i ∈D o} represents the height value of the highest building outline vector point data in the scene frame, H SS =max{y n ∈(DD o )} represents the height value of the highest building vector point data in the field of view, excluding the building in the frame. view It represents the width of the field of view. The height values ​​in the formula refer to the projected height of the building in the field of view, not the actual building height;

[0032] If there is only the second highest building in the field of view in the frame, and the horizontal axis distance between it and the highest building in the field of view is greater than 1 / 2 of the field of view, then the height feature V h The data processing is as follows:

[0033] V h =(H OS -H SHO ) / L view ,

[0034] Other H OS Indicates the height value of the highest building vector point data in the field of view, H SHO Indicates the height value of the vector point data of the second highest building except the highest building in the field of view; in other cases, the height of the building in the field of view is not significant, V h The value is 0.

[0035] Step 5: Output the result of scene feature data processing. The specific method is as follows:

[0036] Step 5.1, Combine volume feature V s With height characteristic V h , weighted fusion is performed through the following formula to obtain the scene feature data processing result V, as shown below:

[0037] V=α·V s +(1-α)·V h ,

[0038] Among them, α represents the adjustable weight relationship between the two information elements;

[0039] Step 5.2, determine whether the data processing of the scene features at all viewpoints is completed. If not, repeat the process of steps 2, 3, 4, and 5.1 in a loop through Python software programming, and process each viewpoint in the continuous three-dimensional viewpoint set OP in turn until the data processing of the scene features of all viewpoints is completed, and output the processing results corresponding to each viewpoint.

[0040] In addition, the present invention also proposes a system for digital processing of scenery features based on the three-dimensional spatial form of the city, including an environment model construction module, a scenery information extraction module, a scenery volume feature digital processing module, a scenery height feature digital processing module, and a scenery feature digital processing result output module. The modules of the system are interrelated. The environment model construction module generates a three-dimensional spatial form scene and a three-dimensional viewpoint set of the city, and determines the field of view range at the viewpoint. The scenery information extraction module generates a building outline vector data set within the field of view at the viewpoint based on the three-dimensional spatial form scene of the city, the viewpoint position, and the field of view range, and extracts the scenery building outline vector data set according to the scenery frame area. The scenery volume feature digital processing module completes the digital processing of the scenery volume feature based on the vector data set to obtain the scenery volume feature information. The scenery height feature digital processing module completes the digital processing of the scenery height feature according to the height and position relationship between the building in the scenery frame and other buildings in the field of view, and obtains the scenery height feature information. The module for outputting the result of the digital processing of the scene features integrates the volume feature and height feature information of the scene, completes the digital processing of the scene features of all viewpoints, and outputs the digital processing result information.

[0041] Among them, the environment model construction module is used to import the urban digital terrain model, urban building model polyhedron and other urban three-dimensional spatial morphology basic model layer files, and unify the coordinate systems of each layer through Python calling the arcpy.SpatialReference interface in the Arcpy library. Further, the surface of the observation area set in the three-dimensional spatial morphology model is rasterized as a whole, and the position of each grid geometric center point is obtained through the RasterToPoint_conversion interface to represent the viewpoint of the grid, and the point element is created as the viewpoint through the arcpy.Point interface, and the height information such as the point element position, height, and line of sight direction SD is set to generate a three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}, where lon i ,lat i represents the coordinates of the i-th viewpoint, h i is the viewpoint height, and N is the number of viewpoints. l =SD-L view / 2, AZ u=SD+L view / 2, determine the field of view of the viewpoint [AZ l ,AZ u ], where A-Z l AZ u Respectively represent the upper and lower boundaries of the field of view, L view is the width of the field of view.

[0042] The view information extraction module is used to obtain the urban building contours at the viewpoint, and to extract and generate the view building contour vector data set based on the field of view and the view frame area. i ,lat i ,h i ),i∈N}, obtain the urban building outline elements at the viewpoint through the Skyline interface, and then generate vector data points from the viewpoint P to each vertex in the outline elements through the Skyline Graph tool. According to the viewpoint field of view, extract the building outline information within the field of view of the viewpoint to form a vector data set D{(x i ,y i )}. Further through the formula OF l =AZ l +(AZ u -AZ l )*0.382,OF u =AZ l +(AZ u -AZ l )*0.618 determines the frame area [OF l ,OF u ], where OF l ,OF u Indicates the upper and lower limits of the scene frame. According to the scene frame area, from the vector data point set D{(x i ,y i )} to extract the building outline vector dataset Do{(x′ j ,y′ j )}; If the data set Do is empty, there is no scene building in the scene frame, and the scene feature digitization result V at this viewpoint is 0.

[0043] The data processing module for the volume characteristics of the scene is used to calculate the building area in the field of view plane and the building area in the scene frame according to the vector data, and complete the data processing to obtain the volume characteristics information of the scene. Substitute the vector data set D{(x i ,y i )}, get the building area S in the field of view BThen according to the formula Substitute the building outline vector dataset Do{(x′ j ,y′ j )}, get the building area S in the scene frame o Finally, according to formula V S =S O / S B Complete the volume feature V s data processing.

[0044] The module for processing the height characteristics of the scene is used to process the height and position relationship between the building in the scene frame and other buildings in the field of view, and obtain the height characteristics of the scene. The module first extracts the height value H of the highest building outline vector point data in the scene frame. OF =max{y i ∈D o}, if H OF When the height value of the highest building in the entire field of view is also obtained, the height value H of the highest building vector data point in the field of view, excluding the buildings in the frame, is further extracted. SS =max{y n ∈(DD o )}, and through V h =(H OF -H SS ) / L view The formula completes the data processing of the scene height feature and obtains the scene height feature information V in this case. h If the highest H in the frame OF If it is only the second highest building in the field of view, then extract the highest point H OF The corresponding horizontal coordinate value x OF , further extract the height value H of the highest building vector data point in the field of view OS =max{y j ∈D} and its corresponding horizontal coordinate x OS If the highest point building is greater than 1 / 2 of the horizontal axis of the field of view, it satisfies Then through V h =(H OF -H OS ) / L view Complete the data processing of the scene height feature and obtain the scene height feature information V in this case h For other cases, it is considered that the height of the buildings in the scenery is not significant, V h The value is 0.

[0045] The scene feature data processing result output module is used to complete the data processing of all viewpoint scene features and output the result information. First, determine the scene volume feature information V s With high feature information Vh The weight relationship a between them is expressed by the formula V = a·V s +(1-a)·V h Perform weighted fusion to obtain the view feature information V at the viewpoint. Repeat the processing for each viewpoint in the three-dimensional viewpoint set OP through Python programming, and finally complete the data processing of the view features at all viewpoints and output the view feature information.

[0046] Beneficial effects: Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method described in the present invention is based on the three-dimensional spatial morphological model and vector data of the city, which overcomes the limitations of the existing methods in viewpoint selection. By characterizing the real field of view of all effective viewpoints within a given urban area, the volume characteristics and height characteristics of the scenery of each viewpoint in the real-time scene are calculated respectively; thereby realizing the digitized processing of the scenery characteristics within an urban area, providing a decision-making basis and scientific support for the control and optimization of urban spatial layout. 2. The method described in the present invention is scientific, universal and repeatable, and can not only evaluate and analyze the current situation of the city, but also provide data information support for the decision-making prediction of different planning schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a technical flow chart of the method of the present invention;

[0048] Figure 2 This is a schematic diagram of the distribution of the viewpoint set after rasterization;

[0049] Figure 3 Schematic diagram of the field of view of the set viewpoint P;

[0050] Figure 4 Schematic diagram of the process of acquiring vector data of the building outline in the field of view of viewpoint P;

[0051] Figure 5 This is a schematic diagram of obtaining the scene information of viewpoint P. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, those skilled in the art will fall within the scope defined by the appended claims of the present application to the modification of various equivalent forms of the present invention.

[0053] The technical method of the present invention is described in detail below with reference to the accompanying drawings and embodiments. Figure 1 The specific steps are as follows:

[0054] Step 1: Collect the basic information of the current three-dimensional spatial form of the city and establish a database scenario of the urban spatial form, as follows:

[0055] Step 1.1, collect basic urban geographic information data based on open source data information, build a digital terrain model of the city, and a polyhedron layer of the urban building model, import it into the geographic information system software ArcGIS, and unify the coordinate system of each layer to WGS84.

[0056] Step 1.2: Rasterize the entire surface of the observation area set in the urban digital terrain model, select the geometric center point of each grid as the viewpoint representing the grid, and create a three-dimensional point element to form a continuous three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}( Figure 2 ), where lon i ,lat i represents the coordinate value of the i-th viewpoint, h i is the viewpoint height, N is the number of viewpoints, and in the embodiment, the viewpoint height is uniformly 1.7 meters, and N is 846.

[0057] Step 1.3, for the three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}, the viewpoint P determines the field of view of the viewpoint P according to the line of sight direction SD [AZ l ,AZ u ]( Figure 3 ), the method is as follows,

[0058] AZ l =SD-L view / 2, AZ u =SD+L view / 2, of which AZ l Indicates the lower boundary of the field of view, AZ u Indicates the upper boundary of the field of view, L view The width of the field of view is usually considered to be 120°.

[0059] Step 2: Get the vector data of the building outline in the field of view and extract the scene information, as follows:

[0060] Step 2.1, for viewpoint P, generate vector data of azimuth angle X and vertical angle Y from viewpoint P to each vertex in the contour line element through the Skyline and Skyline Graph tools in ArcGIS ( Figure 4 );

[0061] Step 2.2, according to the field of view [AZ l ,AZ u ] extracts the building outline information within the field of view at the viewpoint and forms a vector data set D{(x i ,y i )}, with the azimuth as the horizontal axis and the vertical angle as the vertical axis, the outline of the building in the field of view is generated in the two-dimensional field of view;

[0062] Step 2.3, determine the scope of the scene frame according to the golden ratio. Set the spatial range of the horizontal coordinate of the field of view range 38.2% to 61.8% as the scene frame area [OF l ,OF u ]( Figure 5 ). The upper and lower boundaries of the frame l ,OF u OF is obtained by the following formula l =AZ l +(AZ u -AZ l )*0.382,OF u =AZ l +(AZ u -AZ l )*0.618;

[0063] Step 2.4, further extract the vector dataset D{(x i ,y i )} in the view frame area, forming the view building outline vector dataset Do{(x′ j ,y′ j )}. If the data set is empty, This means that there is no background building in the background frame, and the result of the data processing of the background feature is 0.

[0064] Step 3: Data processing of the volume characteristics of the scene. The volume characteristics Vs of the scene reflect the relative prominence of the building volume in the scene frame in the field of vision. The specific method is to calculate the building area S in the scene frame. O The building area S in the field of view B The ratio is as follows:

[0065] V S =S O / S B ;

[0066] The building area S in the field of view is obtained by the following formula B ,

[0067]

[0068] where x i ,y iRepresents the building outline information vector dataset D{(x i ,y i )}. The building area in the field of view is represented by the adjacent points (x i ,y i ), (x i+1 ,y i+1 ) and the X-axis to form the sum of the areas of the trapezoids. The building area S in the scene frame is obtained by the following formula O ,

[0069]

[0070] where x′ j ,y′ j Represents the building outline vector dataset Do{(x′ j ,y′ j )}. The building area in the scene frame is represented by the adjacent point (x′ j ,y′ j ), (x′ j+1 ,y′ j+1 ) is the sum of the areas of the trapezoids formed by the X-axis.

[0071] Step 4: Data processing of the scene height feature. The height feature reflects the relative prominence of the building height in the scene frame in the field of vision. Based on the building outline information in the scene frame, if there is a building with the highest point in the entire field of vision in the scene frame, the scene height feature V h The data processing is as follows:

[0072] V h =(H OF -H SS ) / L view ,

[0073] Among them, H OF =max{y i ∈D o} represents the height value of the highest building outline vector point data in the scene frame, H SS =max{y n ∈(DD o )} represents the height value of the highest building vector point data in the field of view, excluding the building in the frame. view It represents the width of the field of view. The height values ​​in the formula refer to the projected height of the building in the field of view, not the actual building height;

[0074] If there is only the second highest building in the field of view in the frame, and the horizontal axis distance between it and the highest building in the field of view is greater than 1 / 2 of the field of view, then the height feature V h The data processing is as follows:

[0075] V h =(H OS -H SHO ) / L view ,

[0076] Other H OS Indicates the height value of the highest building vector point data in the field of view, H SHO Indicates the height value of the vector point data of the second highest building except the highest building in the field of view; in other cases, the height of the building in the field of view is not significant, V h The value is 0.

[0077] Step 5.1, Combine volume feature V s With height characteristic V h , weighted fusion is performed through the following formula to obtain the scene feature data processing result V, as shown below:

[0078] V=α·V s +(1-α)·V h ,

[0079] Among them, α represents the adjustable weight relationship between the two information elements;

[0080] Step 5.2, determine whether the data processing of the scene features at all viewpoints is completed. If not, repeat the process of steps 2, 3, 4, and 5.1 in a loop through Python software programming, and process each viewpoint in the continuous three-dimensional viewpoint set OP in turn until the data processing of the scene features of all viewpoints is completed, and output the processing results corresponding to each viewpoint.

[0081] The present invention also proposes a scenery feature data processing system based on the three-dimensional spatial form of the city, including an environment model construction module, a scenery information extraction module, a scenery volume feature data processing module, a scenery height feature data processing module, and a scenery feature data processing result output module.

[0082] The modules of the system are interrelated. The environmental model construction module generates a three-dimensional urban space morphological scene and a set of three-dimensional viewpoints, and determines the field of view at the viewpoint. The view information extraction module generates a vector data set of building outlines within the field of view at the viewpoint based on the three-dimensional urban space morphological scene, viewpoint position, and field of view, and extracts the vector data set of the view building outlines according to the view frame area. The view volume feature data processing module completes the data processing of the view volume feature based on the vector data set to obtain the view volume feature information. The view height feature data processing module completes the data processing of the view height feature according to the height and position relationship between the building in the view frame and other buildings in the field of view, and obtains the view height feature information. The view feature data processing result output module integrates the view volume feature and height feature information, completes the view feature data processing of all viewpoints, and outputs the data processing result information.

[0083] Among them, the environment model construction module is used to import the urban digital terrain model, urban building model polyhedron and other urban three-dimensional spatial morphology basic model layer files, and unify the coordinate systems of each layer through Python calling the arcpy.SpatialReference interface in the Arcpy library, and further rasterize the entire surface of the observation area set in the three-dimensional spatial morphology model. The position of each grid geometric center point is obtained through the RasterToPoint_conversion interface to represent the viewpoint of the grid, and the arcpy.Point interface is used to create a point feature as the viewpoint, and the point feature position, height, line of sight direction SD and other height information are set to generate a three-dimensional viewpoint set OP{(lon i ,lat i ,h i ), i∈N}, where lon i ,lat i represents the coordinates of the i-th viewpoint, h i is the viewpoint height, and N is the number of viewpoints. l =SD-L view / 2, AZ u =SD+L view / 2, determine the field of view of the viewpoint [AZ l , A.Z. u ], where A-Z l AZ u Respectively represent the upper and lower boundaries of the field of view, L view is the width of the field of view.

[0084] The view information extraction module is used to obtain the urban building contours at the viewpoint, and to extract and generate the view building contour vector data set based on the field of view and the view frame area. i ,lati ,h i ), i∈N}, obtain the location information of a viewpoint P in the viewpoint, obtain the urban building outline elements at the viewpoint through the Skyline interface, and then generate vector data points from the viewpoint P to each vertex in the outline elements through the Skyline Graph tool. According to the viewpoint field of view, extract the building outline information within the field of view of the viewpoint to form a vector data set D{(x i ,y i )}. Further through the formula OF I =AZ I +(AZ u -AZ I )*0.382,OF u =AZ I +(AZ u -AZ I )*0.618 determines the frame area [OF I ,OF u ], where OF I ,OF u Indicates the upper and lower limits of the scene frame. According to the scene frame area, from the vector data point set D{(x i ,y i )} to extract the building outline vector dataset Do{(x′ j , y′ j )}; If the data set Do is empty, there is no scene building in the scene frame, and the scene feature digitization result V at this viewpoint is 0.

[0085] The data processing module for the volume characteristics of the scene is used to calculate the building area in the field of view plane and the building area in the scene frame according to the vector data, and complete the data processing to obtain the volume characteristics information of the scene. Substitute the vector data set D{(x i ,y i )}, get the building area S in the field of view B Then according to the formula Substitute the building outline vector dataset Do{(x′ j , y′ j )}, get the building area S in the scene frame O Finally, according to formula V S =S o / S B Complete the volume feature V s data processing.

[0086] The module for processing the height characteristics of the scene is used to process the height and position relationship between the building in the scene frame and other buildings in the field of view, and obtain the height characteristics of the scene. The module first extracts the height value H of the highest building outline vector point data in the scene frame. OF =max{y i ∈D o}, if H OF When the height value of the highest building in the entire field of view is also obtained, the height value H of the highest building vector data point in the field of view, excluding the buildings in the frame, is further extracted. SS =max{y n ∈(DD o )}, and through V h =(H OF -H SS ) / L view The formula completes the data processing of the scene height feature and obtains the scene height feature information V in this case. h If the highest H in the frame OF If it is only the second highest building in the field of view, then extract the highest point H OF The corresponding horizontal coordinate value x OF , further extract the height value H of the highest building vector data point in the field of view OS =max{y j ∈D} and its corresponding horizontal coordinate x OS If the highest point building is greater than 1 / 2 of the horizontal axis of the field of view, it satisfies Then through V h =(H OF -H OS ) / L view Complete the data processing of the scene height feature and obtain the scene height feature information V in this case h For other cases, it is considered that the height of the buildings in the scenery is not significant, V h The value is 0.

[0087] The scene feature data processing result output module is used to complete the data processing of all viewpoint scene features and output the result information. First, determine the scene volume feature information V s With high feature information V h The weight relationship α between them is given by the formula V = α·V s +(1-α)•V h Perform weighted fusion to obtain the view feature information V at the viewpoint. Repeat the processing for each viewpoint in the three-dimensional viewpoint set OP through Python programming, and finally complete the data processing of the view features at all viewpoints and output the view feature information.

Claims

1. A method for processing scene features digitally based on the three-dimensional spatial form of a city, characterized in that: The method comprises the following steps: Step 1: Collect the basic information of the three-dimensional spatial form of the city and build the urban spatial form database scene; Step 2, extracting vector data of the building outline in the field of view and obtaining the scene information; Step 3, according to the relationship between the building area in the scene frame and other building areas in the field of view, obtain the data processing result of the scene volume feature; Step 4, obtaining the result information of the data processing of the height feature of the scene according to the height and position relationship between the building in the scene frame and other buildings in the field of view; Step 5, according to the relationship between the volume feature and the height feature of the scene, complete the data processing of the scene feature in sequence and output all the result information; Step 5.1, Combine volume feature V s With height characteristic V h , weighted fusion is performed through the following formula to obtain the scene feature data processing result V, as shown below: V=α·V s +(1-α)·V h , Among them, α represents the adjustable weight relationship between the two information elements; Step 5.2, determine whether the data processing of the scene features at all viewpoints is completed. If not, repeat the process of steps 2, 3, 4, and 5.1 in a loop through Python software programming, and process each viewpoint in the three-dimensional viewpoint set OP in turn until the data processing of the scene features of all viewpoints is completed, and output the processing results corresponding to each viewpoint.

2. The method for digitizing scene features based on the three-dimensional spatial form of a city according to claim 1, characterized in that: The step 1 comprises the following steps: Step 1.1, collect basic urban geographic information data based on open source data information, build urban digital terrain model and urban building model polyhedron layer, import them into the geographic information system software ArcGIS, and unify the coordinate system of each model layer; Step 1.2, rasterize the entire surface of the observation area set in the urban digital terrain model, select the geometric center point of each grid as the viewpoint representing the grid, and generate three-dimensional point elements to form a three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}; where lon i ,lat i represents the coordinates of the i-th viewpoint, h i is the viewpoint height, N is the number of viewpoints; Step 1.3, for the three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}, the viewpoint P determines the field of view of the viewpoint P according to the line of sight direction SD [AZ l ,AZ u ], the method is as follows, AZ l =SD-L view / 2, AZ u =SD+L view / 2, of which AZ l Indicates the lower boundary of the field of view, AZ u Indicates the upper boundary of the field of view, L view is the width of the field of view, which is assumed to be 120°.

3. The method for digitizing scene features based on the three-dimensional spatial form of a city according to claim 1, characterized in that: The step 2 comprises the following steps: Step 2.1, for viewpoint P, generate vector data of azimuth angle X and vertical angle Y from viewpoint P to each vertex in the contour line element through the Skyline and Skyline Graph tools in ArcGIS; Step 2.2, according to the field of view [AZ l ,AZ u ] extracts the building outline information within the field of view at the viewpoint and forms a vector data set D{(x i ,y i )}, with the azimuth as the horizontal axis and the vertical angle as the vertical axis, the outline of the building in the field of view is generated in the two-dimensional field of view; Step 2.3, according to the golden ratio, set the spatial range of the horizontal coordinate of the field of view from 38.2% to 61.8% as the view frame area [OF l ,OF u ]; the upper and lower boundaries of the scene frame l 、OF u Obtained by the following formula OF l =THE l +(THE u -THE l )*0.382,OF u =THE l +(THE u -THE l )*0.618; Step 2.4, further extract the vector dataset D{(x i ,y i )} in the context frame, forming the context building outline vector dataset Do{(x' j ,y'j)}; if the data set is empty, If there is no background building in the background frame, the result of the data processing of the background feature is 0.

4. The method for digitizing scene features based on the three-dimensional spatial form of a city according to claim 1, characterized in that: The step 3 is as follows: The volume feature Vs reflects the relative prominence of the building volume in the frame. The specific method is to calculate the building area S in the frame. O The building area S in the field of view B The ratio is as follows: V S =S O / S B ; Building area in view S B and the building area S in the frame O Obtained by the following formulas: where x i ,y i Represents the building outline information vector dataset D{(x i ,y i )}, x' j ,y' j Represents the building outline vector dataset Do((x' j ,y' j )}, the building area is expressed as the sum of the areas of each trapezoid formed by adjacent data points and the X-axis.

5. The method for digitizing scene features based on the three-dimensional spatial form of a city according to claim 1, characterized in that: The step 4 is specifically as follows: The height feature reflects the relative prominence of the building height in the frame. Based on the building outline information in the frame, if there is a building with the highest point in the entire field of view in the frame, the height feature V h The data processing is as follows: V h =(H OF -H SS ) / L view , Among them, H OF =max{y i ∈D o } represents the height value of the highest building outline vector point data in the scene frame, H SS =max{y n ∈(DD o )} represents the height value of the highest building vector point data in the field of view, excluding the building in the frame; L view It indicates the width of the field of view; the height values ​​in the formula refer to the projected height of the building in the field of view, not the actual building height; Do is a data set; If there is only the second highest building in the field of view in the frame, and the horizontal axis distance between it and the highest building in the field of view is greater than 1 / 2 of the field of view, then the height feature V h The data processing is as follows: V h =(H OS -H SHO ) / L view Among them, H OS Indicates the height value of the highest building vector point data in the field of view, H SHO Indicates the height value of the vector point data of the second highest building except the highest building in the field of view; in other cases, the height of the building in the field of view is not significant, V h The value is 0.

6. A system for processing scene characteristics data based on the urban three-dimensional space form according to the method of claim 1, characterized in that: The system includes an environment model building module, a scene information extraction module, a scene volume feature data processing module, a scene height feature data processing module, and a scene feature data processing result output module: The modules of the system are interrelated. The environment model construction module generates a three-dimensional urban space morphological scene and a three-dimensional viewpoint set, and determines the field of view at the viewpoint; the scene information extraction module generates a building outline vector data set within the field of view at the viewpoint based on the three-dimensional urban space morphological scene, viewpoint position, and field of view, and extracts the scene building outline vector data set according to the scene frame area; the scene volume feature data processing module completes the data processing of the scene volume feature based on the vector data set to obtain the scene volume feature information; the scene height feature data processing module completes the data processing of the scene height feature according to the height and position relationship between the building in the scene frame and other buildings in the field of view, and obtains the scene height feature information; the scene feature data processing result output module integrates the scene volume feature and height feature information, completes the scene feature data processing of all viewpoints, and outputs the data processing result information.

7. A system for processing scene characteristics data based on urban three-dimensional space form as claimed in claim 6, characterized in that: The environment model construction module is used to import the city digital terrain model, city building model polyhedron and other city three-dimensional space morphology basic model layer files, and unify the coordinate systems of each model layer by calling the arcpy.SpatialReference interface in the Arcpy library through Python; further rasterize the entire surface of the observation area set in the three-dimensional space morphology model, obtain the position of each grid geometric center point to represent the viewpoint of the grid through the RasterToPoint_conversion interface, and create a point element as the viewpoint through the arcpy.Point interface, and set the point element position, height, line of sight direction SD and other height information to generate a three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}, where lon i ,lat i represents the coordinates of the i-th viewpoint, h i is the viewpoint height, N is the number of viewpoints; further through the formula AZ l =SD-L view / 2, AZ u =SD+L view / 2, determine the field of view of the viewpoint [AZ l ,AZ u ], where A-Z l AZ u Respectively represent the upper and lower boundaries of the field of view, L view is the width of the field of view.

8. A system for processing scene characteristics data based on urban three-dimensional space form as claimed in claim 6, characterized in that: The view information extraction module is used to obtain the urban building contour line at the viewpoint, and to extract and generate the view building contour vector data set according to the field of view and the view frame area; the module firstly extracts the urban building contour line at the viewpoint according to the field of view and the view frame area based on the three-dimensional viewpoint set OP{(lon i ,lat i ,h i ),i∈N}, obtain the urban building outline elements at the viewpoint through the Skyline interface, and then generate vector data points from the viewpoint P to each vertex in the outline elements through the Skyline Graph tool; according to the viewpoint field of view, extract the building outline information within the field of view of the viewpoint to form a vector data set D{(x i ,y i )}; Further through the formula OF l =AZ l +(AZ u -AZ l )*0.382,OF u =AZ l +(AZ u -AZ l )*0.618 determines the frame area [OF l ,OF u ], where OF l ,OF u Indicates the upper and lower limits of the scene frame, and the vector data point set D{(x i ,y i )} to extract the building outline vector dataset Do{(x' j ,y' j )}; If the data set Do is empty, there is no scene building in the scene frame, and the scene feature digitization result V at this viewpoint is 0.

9. A system for processing scene characteristics data based on urban three-dimensional space form as claimed in claim 6, characterized in that: The module for processing the volume characteristics of the scene into digital form is used to calculate the building area in the visual plane and the building area in the scene frame according to the vector data, and complete the digital process to obtain the volume characteristics information of the scene; the module first calculates the building area in the visual plane and the building area in the scene frame according to the vector data; Substitute the vector data set D{(x i ,y i )}, get the building area S in the field of view B , and then according to the formula Substitute the building outline vector dataset Do{(x' j ,y' j )}, get the building area S in the scene frame O Finally, according to formula V S =S O / S B Complete the volume feature V s Data processing; The height feature data processing module is used to perform data processing based on the height and position relationship between the building in the view frame and other buildings in the field of view to obtain the height feature information of the view. The module first extracts the height value H of the highest building outline vector point data in the view frame. OF =max{y i ∈D o }, if H OF When the height value of the highest building in the entire field of view is also obtained, the height value H of the highest building vector data point in the field of view, excluding the buildings in the frame, is further extracted. SS =max{y n ∈(DD o )}, and through V h =(H OF -H SS ) / L view The formula completes the data processing of the scene height feature and obtains the scene height feature information V in this case. h ; If the highest H in the frame OF If it is only the second highest building in the field of view, then extract the highest point H OF The corresponding horizontal coordinate value x OF , further extract the height value H of the highest building vector data point in the field of view OS =max{y j ∈D} and its corresponding horizontal coordinate x OS If the highest point building is greater than 1 / 2 of the horizontal axis in the field of view, it satisfies Then through V h =(H OF -H OS ) / L view Complete the data processing of the scene height feature and obtain the scene height feature information V in this case h For other cases, it is considered that the height of the building in the scenery is not significant, V h The value is 0; The output module of the result of the data processing of the scene feature is used to complete the data processing of the scene feature of all viewpoints and output the result information. First, the scene volume feature information V s With high feature information V h The weight relationship α between them is given by the formula V = α·V s +(1-α)·V h Perform weighted fusion to obtain the scene feature information V at the viewpoint, and repeat the processing for each viewpoint in the three-dimensional viewpoint set OP through Python programming, and finally complete the data processing of the scene features at all viewpoints and output the scene feature information.

Images