Geographic vector data simulation modeling method, device and electronic equipment

Abstract

The present invention provides a geographic vector data simulation modeling method, device and electronic device, wherein the geographic vector data simulation modeling method comprises: determining a real geographic range to be simulated, and determining at least two geographic registration points within the real geographic range to be simulated; determining a simulation space range based on the real geographic range to be simulated, and determining at least two simulation registration points within the simulation space range; obtaining geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system; parsing the geographic vector data to be processed to obtain multiple geographic coordinate sequences of the geographic vector data to be processed; based on the geographic registration points and the simulation registration points, performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates; and obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates. The present invention improves the visualization effect of the simulation model.

Description

Technical Field

[0001] The present invention relates to the field of simulation technology, and in particular to a geographic vector data simulation modeling method, device and electronic equipment. Background Art

[0002] Vector data model, also known as discrete object model, is a data format that uses discrete objects to represent spatial elements on the earth's surface. Geographic vector data is a map graphic or geographic entity represented by two-dimensional coordinates in a rectangular coordinate system. It mainly describes the spatial position and geometric form of geographic objects and also contains some semantic attribute information.

[0003] As known from the related art, the spatial location information contained in the vector data is usually visualized based on the Geographic Information System (GIS) software. The common visualization operation form is to overlay the display on the map base map, and use points, polylines, polygons and other shapes to represent different types of geographic vector data.

[0004] However, the simple point, line and surface styles displayed on a two-dimensional plane or three-dimensional terrain surface are relatively simple and cannot form a realistic three-dimensional terrain model. Especially when the sampling interval of geographic vector data is large, it is displayed as a transitional and stiff broken line segment in the GIS system, with poor visualization effect and poor restoration of the original geographic elements. Summary of the invention

[0005] The present invention provides a geographic vector data simulation modeling method, device and electronic equipment to solve the defects of single visualization effect and poor restoration of geographic vector data in the prior art, realize automatic simulation modeling of the geographic vector data to be processed, and generate a simulation model corresponding to the geographic vector data to be processed, which has a morphology derived from real surveying and mapping data, a texture close to the real effect, and a high visualization effect.

[0006] The present invention provides a geographic vector data simulation modeling method, the method comprising: determining a real geographic range to be simulated, and determining at least two geographic registration points within the real geographic range to be simulated; determining a simulation space range based on the real geographic range to be simulated, and determining at least two simulation registration points within the simulation space range, wherein the simulation registration points are registered with the geographic registration points; acquiring geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system; parsing the geographic vector data to be processed to obtain multiple geographic coordinate sequences of the geographic vector data to be processed; based on the geographic registration points and the simulation registration points, performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates; and obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0007] According to a geographic vector data simulation modeling method provided by the present invention, based on the geographic registration point and the simulation registration point, each geographic coordinate in the geographic coordinate sequence is transformed to obtain a simulation coordinate, which specifically includes: determining the horizontal span of the real geographic range to be simulated, and based on the span, according to the geographic registration point and the simulation registration point, each geographic coordinate in the geographic coordinate sequence is transformed to obtain a simulation coordinate.

[0008] According to a geographic vector data simulation modeling method provided by the present invention, the geographic registration points include a first geographic registration point and a second geographic registration point, and the simulation registration points include a first simulation registration point and a second simulation registration point; the coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate based on the span according to the geographic registration point and the simulation registration point specifically includes: if the span is greater than or equal to a span threshold, the projection coordinates of the first geographic registration point are obtained based on the first geographic registration point, the projection coordinates of the second geographic registration point are obtained based on the second geographic registration point, and the projection coordinates of the geographic coordinates are obtained based on the geographic coordinates; based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point, and the projection coordinates of the geographic coordinates, the coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinates.

[0009] According to a geographic vector data simulation modeling method provided by the present invention, the first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point and the projection coordinates of the geographic coordinates, coordinate conversion is performed on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates using the following formula:

[0010]

[0011]

[0012] Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lonProj represents the longitude value of the projection coordinate of the geographic coordinate; startLonProj represents the longitude value of the projection coordinate of the first geographic reference point; endLonProj represents the longitude value of the projection coordinate of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; latProj represents the latitude value of the projection coordinate of the geographic coordinate; startLatProj represents the latitude value of the projection coordinate of the first geographic reference point; endLatProj represents the latitude value of the projection coordinate of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

[0013] According to a geographic vector data simulation modeling method provided by the present invention, the geographic registration points include a first geographic registration point and a second geographic registration point, and the simulation registration points include a first simulation registration point and a second simulation registration point; the coordinate transformation of each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the geographic registration point and the simulation registration point based on the span specifically includes: if the span is less than a span threshold, the coordinate transformation of each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point.

[0014] According to a geographic vector data simulation modeling method provided by the present invention, the first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point, the coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate is implemented by the following formula:

[0015]

[0016]

[0017] Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lon represents the longitude value of the geographic coordinate; startLon represents the longitude value of the first geographic reference point; endLon represents the longitude value of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; lat represents the latitude value of the geographic coordinate; startLat represents the latitude value of the first geographic reference point; endLat represents the latitude value of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

[0018] According to a geographic vector data simulation modeling method provided by the present invention, the simulation model of the geographic vector data to be processed is obtained based on the simulation coordinates, specifically including: processing each of the geographic coordinate sequences to obtain a spline curve corresponding to each of the geographic coordinate sequences, wherein the simulation coordinates of each geographic coordinate in the geographic coordinate sequence are used as control points in the spline curve; adding a grid body between adjacent control points of the spline curve to obtain a spline grid body; and obtaining the simulation model of the geographic vector data to be processed based on the spline grid body.

[0019] According to a geographic vector data simulation modeling method provided by the present invention, before obtaining the simulation model of the geographic vector data to be processed based on the spline mesh body, the method also includes: adding material effects to the spline mesh body to obtain a processed spline mesh body, and using the processed spline mesh body as the final spline mesh body, wherein the material effects match the features corresponding to the geographic coordinate sequence.

[0020] The present invention also provides a geographic vector data simulation modeling device, which includes: a determination module, which is used to determine a real geographic range to be simulated, and determine at least two geographic registration points within the real geographic range to be simulated, and determine a simulation space range based on the real geographic range to be simulated, and determine at least two simulation registration points within the simulation space range, wherein the simulation registration points are registered with the geographic registration points; an acquisition module, which is used to acquire geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system; a parsing module, which is used to parse the geographic vector data to be processed and obtain multiple geographic coordinate sequences of the geographic vector data to be processed; a conversion module, which is used to perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence based on the geographic registration points and the simulation registration points to obtain simulation coordinates; and a processing module, which is used to obtain a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0021] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the geographic vector data simulation modeling method as described in any one of the above is implemented.

[0022] The geographic vector data simulation modeling method, device and electronic device provided by the present invention perform coordinate conversion on each geographic coordinate in a geographic coordinate sequence based on geographic registration points and simulation registration points to obtain simulation coordinates, and obtain a simulation model of the geographic vector data to be processed according to the simulation coordinates, thereby realizing automatic simulation modeling of the geographic vector data to be processed, and generating a simulation model with high visualization effect corresponding to the geographic vector data to be processed, thereby improving the modeling efficiency in the simulation modeling process and the visualization effect of the simulation model. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is one of the flow charts of the geographic vector data simulation modeling method provided by the present invention;

[0025] Figure 2 It is a schematic diagram of coordinate registration of the simulation space range provided by the present invention;

[0026] Figure 3 It is a schematic diagram of the result of the simulation modeling of linear geographic vector data provided by the present invention;

[0027] Figure 4 It is a schematic diagram of a process of converting each geographic coordinate in a geographic coordinate sequence into a simulation coordinate based on a span according to a geographic registration point and a simulation registration point provided by the present invention;

[0028] Figure 5 It is a schematic diagram of a flow chart of a simulation model for obtaining the geographic vector data to be processed based on simulation coordinates provided by the present invention;

[0029] Figure 6 It is a schematic diagram of the spline curve control points provided by the present invention;

[0030] Figure 7 It is a high-altitude perspective diagram of the result of the simulation modeling of the planar geographic vector data provided by the present invention;

[0031] Figure 8It is a low-altitude perspective schematic diagram of the result of the simulation modeling of the planar geographic vector data provided by the present invention;

[0032] Fig. 9 It is a structural schematic diagram of the geographic vector data simulation modeling device provided by the present invention;

[0033] Fig.10 It is a structural schematic diagram of the electronic device provided by the present invention.

[0034] Reference numerals:

[0035] Control points: 601 Spline curve: 602 DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0037] The geographic vector data simulation modeling method provided by the present invention can automatically perform simulation modeling on the geographic vector data to be processed, and generate a simulation model with high visualization effect corresponding to the geographic vector data to be processed, thereby improving the modeling efficiency in the simulation modeling process and the visualization effect of the simulation model.

[0038] It should be noted that the geographic vector data simulation modeling method provided by the present invention can be applied to Unreal Engine or other engines, and the application scenario is not specifically limited in the present invention. In the present invention, for the sake of convenience, the scenario applied to Unreal Engine is used as an example for description.

[0039] In order to further introduce the geographic vector data simulation modeling method provided by the present invention, Figure 1 Provide explanation.

[0040] Figure 1 It is one of the flow charts of the geographic vector data simulation modeling method provided by the present invention.

[0041] In an exemplary embodiment of the present invention, Figure 1 It can be seen that the geographic vector data simulation modeling method may include steps 110 to 160, and each step will be introduced below.

[0042] In step 110 , a real geographic range to be simulated is determined, and at least two geographic registration points are determined within the real geographic range to be simulated.

[0043] In step 120, a simulation space range is determined based on the real geographical range to be simulated, and at least two simulation registration points are determined within the simulation space range, wherein the simulation registration points are registered with the geographical registration points.

[0044] The simulation system developed based on Unreal Engine limits the spatial scope involved in the simulation (corresponding to the simulation spatial scope), that is, the simulation scene only covers a specific range of the earth (corresponding to the real geographical scope to be simulated). In the application process, it is necessary to align the boundary coordinates of the simulation spatial scope with the real geographical coordinates within the real geographical scope to be simulated.

[0045] In one embodiment, the real geographic range to be simulated can be described by the longitude and latitude of two points, the southwest corner (startLon, startLat) and the northeast corner (endLon, endLat), and used as geographic alignment points. The corresponding real geographic range to be simulated is a quadrilateral located on the surface of the earth with a certain curvature on all four sides.

[0046] In another embodiment, the simulation space range can be a three-dimensional rectangular coordinate system, and the geographical direction corresponding to the three directions of "XYZ" is "southeast sky". In one example, the starting coordinates of the lower left corner (startX, startY) and the upper right corner coordinates (endX, endY) can be set as simulation alignment points. The Z direction is the direction of terrain undulations and does not need to be considered temporarily when aligning the earth's surface range (corresponding to the real geographical range to be simulated). It can be understood that the real geographical range to be simulated is aligned with the simulation space range.

[0047] In yet another example, combining Figure 2 For illustration, the southwest corner (startLon, startLat) within the real geographic range to be simulated (corresponding to the coordinate system where the real geographic coordinates are located) can be called the first geographic registration point, the northeast corner (endLon, endLat) can be called the second geographic registration point, and the starting coordinates (startX, startY) of the lower left corner within the simulation space range (corresponding to the coordinate system where the simulation space coordinates are located) can be called the first simulation registration point, and the upper right corner coordinates (endX, endY) can be called the second simulation registration point. Among them, the first geographic registration point is aligned with the first simulation registration point coordinates, and the second geographic registration point is aligned with the second simulation registration point coordinates.

[0048] In step 130, geographic vector data to be processed is obtained, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system.

[0049] Geographic vector data includes a variety of data formats, such as Shapefile, KML, GML, GPX, OSM, GeoJSON and other data formats. Geographic vector data can be used to describe point-line-surface geographic elements such as points of interest, roads, pipelines, rivers, and lakes. In order to unify the data input method and facilitate subsequent processing, an exchange format can be determined as the simulation system input. In one embodiment, the geographic vector data to be processed can be preprocessed to obtain processed geographic vector data to be processed, and the processed geographic vector data to be processed can be used as the final geographic vector data to be processed. Among them, the final geographic vector data to be processed can be understood as the simulation system input described above.

[0050] In one embodiment, since the GeoJSON data format can store geographic coordinates as text in the form of JavaScript Object Notation (JSON), the attributes of spatial objects are stored in a multi-level text-type data structure, including polymorphic coordinate data such as points, lines, and polygons. Compared with other formats, the GeoJSON data format usually has less markup overhead and better interchangeability between different systems, so in this embodiment, the GeoJSON data format can be used as a unified modeling input format. Preprocessing the geographic vector data to be processed to obtain the processed geographic vector data to be processed can be understood as converting the geographic vector data to be processed to be modeled into the GeoJSON format.

[0051] In step 140, the geographic vector data to be processed is parsed to obtain a plurality of geographic coordinate sequences of the geographic vector data to be processed.

[0052] In one embodiment, the geographic vector data to be processed in GeoJSON format can be read, and for each geographic vector object, the geographic coordinate sequence contained therein can be parsed. Among them, the geographic vector data to be processed can be composed of multiple geographic vector objects, wherein the geographic vector object can be represented by a geographic coordinate sequence. It can be understood that the coordinates corresponding to the geographic coordinate sequence can belong to the same coordinate system as the real geographic range to be simulated. The geographic coordinate sequence can include the longitude and latitude values ​​of a certain geographic location. It should be noted that the simulation modeling of the geographic vector data to be processed to obtain the simulation model of the geographic vector data to be processed can be understood as being achieved by simulating the geographic vector object to obtain the simulation model of the geographic vector object. The simulation model of the geographic vector data to be processed can be composed of multiple simulation models of geographic vector objects.

[0053] In step 150, based on the geographic registration point and the simulation registration point, coordinate transformation is performed on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate.

[0054] In step 160, a simulation model of the geographic vector data to be processed is obtained based on the simulation coordinates.

[0055] In one embodiment, continue to combine Figure 2 For illustration, the geographic coordinates may correspond to (Lon, Lat) in the diagram, and the simulation coordinates may correspond to (x, y) in the diagram. In the application process, based on the geographic alignment points (the first geographic alignment point (startLon, startLat) and the second geographic alignment point (endLon, endLat)) and the simulation alignment points (the first simulation alignment point (startX, startY) and the second simulation alignment point (endX, endY)), the coordinates of each geographic coordinate (Lon, Lat) in the geographic coordinate sequence may be transformed to obtain the simulation coordinates (x, y). Furthermore, based on the simulation coordinates (x, y), a simulation model of the geographic vector data to be processed may be obtained.

[0056] Figure 3 The schematic diagram shows the result of simulating and modeling linear geographic vector data based on the geographic vector data simulation modeling method provided by the present invention. Figure 3 As shown, a road model with good visibility is formed, whose direction is based on real surveying and mapping data, whose appearance conforms to the characteristics of the road, and whose modeling visualization effect is high. Through this embodiment, automatic simulation modeling of geographic vector data is realized, and a simulation model corresponding to the geographic vector data to be processed is generated, whose morphology is derived from real surveying and mapping data, whose texture is close to the real effect, and whose visualization effect is high. In addition, the simulation modeling process of the geographic vector data to be processed is an automated program, and its efficiency is improved compared with manual modeling.

[0057] The geographic vector data simulation modeling method provided by the present invention performs coordinate transformation on each geographic coordinate in a geographic coordinate sequence based on geographic registration points and simulation registration points to obtain simulation coordinates, and obtains a simulation model of the geographic vector data to be processed according to the simulation coordinates, thereby realizing automatic simulation modeling of the geographic vector data to be processed, and generating a simulation model corresponding to the geographic vector data to be processed with high visualization effect, thereby improving the modeling efficiency in the simulation modeling process and the visualization effect of the simulation model.

[0058] In order to further introduce the geographic vector data simulation modeling method provided by the present invention, the process of performing coordinate transformation on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates based on geographic registration points and simulation registration points will be described below.

[0059] In an exemplary embodiment of the present invention, based on the geographic registration point and the simulation registration point, coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate can be implemented by the following steps:

[0060] The span of the real geographic range to be simulated in the horizontal direction is determined, and based on the span, each geographic coordinate in the geographic coordinate sequence is converted into a simulated coordinate according to the geographic reference point and the simulation reference point. It should be noted that the specific direction of the horizontal direction is not limited in the present invention. In an example, the span in the horizontal direction can be a span along the latitude direction or a span along the longitude direction.

[0061] In an exemplary embodiment of the present invention, the geographic registration point may include a first geographic registration point and a second geographic registration point, and the simulation registration point may include a first simulation registration point and a second simulation registration point. Figure 4 It can be seen that performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate based on the span according to the geographic registration point and the simulation registration point may include step 410 and step 420, and each step will be introduced below.

[0062] In step 410, if the span is greater than or equal to the span threshold, the projected coordinates of the first georeferenced point are obtained based on the first georeferenced point, the projected coordinates of the second georeferenced point are obtained based on the second georeferenced point, and the projected coordinates of the geographic coordinates are obtained based on the geographic coordinates.

[0063] In one embodiment, the span threshold may be adjusted according to actual conditions, and is not specifically limited in this embodiment. In one example, the span threshold may be ten kilometers.

[0064] It is understandable that if the horizontal span of the real geographic range to be simulated is greater than or equal to the span threshold, it can be considered that the simulation space range is large, and the curvature of the earth has significantly affected the position-related calculations in the simulation process. In the application process, it is necessary to realize the conversion between simulation coordinates and geographic coordinates through global plane projection.

[0065] In one example, the EPSG:3857 projection standard can be used to project the earth's surface into a rectangle on a plane. In the application process, the geographic coordinates (lon, lat) represented by longitude and latitude can be converted into the projection coordinates of the geographic coordinates (lonProj, latProj). The first georeferenced point (startLon, startLat) represented by longitude and latitude can be converted into the projection coordinates of the first georeferenced point (startLonProj, startLatProj). The second georeferenced point (endLon, endLat) represented by longitude and latitude can be converted into the projection coordinates of the second georeferenced point (endLonProj, endLatProj).

[0066] In step 420, based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point and the projection coordinates of the geographic coordinates, coordinate transformation is performed on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates.

[0067] In one embodiment, the first geo-reference point (startLon, startLat) is aligned with the first simulation reference point (startX, startY), and the second geo-reference point (endLon, endLat) is aligned with the second simulation reference point (endX, endY). Based on the first simulation reference point, the second simulation reference point, the projection coordinates of the first geo-reference point, the projection coordinates of the second geo-reference point, and the projection coordinates of the geo-reference point, the coordinate conversion of each geo-reference in the geo-reference sequence to obtain the simulation coordinates can be implemented by the following formula:

[0068]

[0069]

[0070] Wherein, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lonProj represents the longitude value of the projection coordinate of the geographic coordinate; startLonProj represents the longitude value of the projection coordinate of the first geographic reference point; endLonProj represents the longitude value of the projection coordinate of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; latProj represents the latitude value of the projection coordinate of the geographic coordinate; startLatProj represents the latitude value of the projection coordinate of the first geographic reference point; endLatProj represents the latitude value of the projection coordinate of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point. Through this embodiment, the geographic location coordinates contained in the geographic vector data to be processed can be converted into corresponding coordinates in the simulation space.

[0071] In another exemplary embodiment of the present invention, based on the span, the coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate can also be implemented in the following manner:

[0072] If the span is less than the span threshold, based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point, coordinate transformation is performed on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate.

[0073] It can be understood that if the horizontal span of the real geographic range to be simulated is less than the span threshold, it can be considered that the simulation space range is small and the scale error caused by the earth's curvature is small. The real geographic range corresponding to the simulation can be approximately regarded as a rectangle, and the proportional transformation formula can be directly used to convert between geographic coordinates (lon, lat) and simulation coordinates (x, y).

[0074] In one embodiment, the first geo-reference point is set to be aligned with the first simulation reference point, and the second geo-reference point is set to be aligned with the second simulation reference point. Based on the first simulation reference point, the second simulation reference point, the first geo-reference point, and the second geo-reference point, coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate can be achieved by using the following formula:

[0075]

[0076]

[0077] Wherein, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lon represents the longitude value of the geographic coordinate; startLon represents the longitude value of the first geographic reference point; endLon represents the longitude value of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; lat represents the latitude value of the geographic coordinate; startLat represents the latitude value of the first geographic reference point; endLat represents the latitude value of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point. Through this embodiment, the geographic location coordinates contained in the geographic vector data to be processed can be converted into corresponding coordinates in the simulation space.

[0078] It should be noted that in the traditional surveying and mapping field, the relative orientation of the coordinate axis follows the right-hand system standard. In the northern hemisphere, the three directions of "longitude, latitude and height" correspond to "northeast sky", while the simulation system based on Unreal Engine generally uses a left-handed coordinate system, and the geographical orientation corresponding to the three directions of "XYZ" is "southeast sky". In the coordinate calculation, the Y direction coordinate value will have the opposite sign. However, the proportional conversion method (corresponding to Formula 3 and Formula 4) used in this embodiment can avoid this error, so there is no need to perform special processing on the Y direction coordinate.

[0079] The present invention will combine Figure 5 The process of obtaining a simulation model of geographic vector data to be processed based on simulation coordinates is described.

[0080] Figure 5 It is a schematic diagram of the flow of a simulation model for obtaining the geographic vector data to be processed based on simulation coordinates provided by the present invention.

[0081] In an exemplary embodiment of the present invention, Figure 5 It can be known that the simulation model for obtaining the geographic vector data to be processed based on the simulation coordinates may include steps 510 to 530, and each step will be introduced below.

[0082] In step 510, each geographic coordinate sequence is processed to obtain a spline curve corresponding to each geographic coordinate sequence, wherein the simulated coordinates of each geographic coordinate in the geographic coordinate sequence are used as control points in the spline curve.

[0083] In one embodiment, each geographic coordinate sequence can be initialized as a spline curve, and the generated simulation coordinate sequence (corresponding to the sequence composed of simulation coordinates) is used as the coordinates of the control points of the spline curve, so that the geographic vector form described by the spline curve can be obtained. It can be understood that the geographic vector data to be processed can be composed of multiple geographic vector objects (which can be understood as ground objects), and the geographic vector objects can be represented by geographic coordinate sequences. Figure 6 It can be seen that when the control point 601 of the spline curve 602 determines the trend and shape of the curve, after the coordinates of the control point 601 are assigned, the shape of the spline curve 602 will also change accordingly, and finally the geographic vector represented by the geographic coordinate sequence is described by a smooth curve.

[0084] In another embodiment, in the process of assigning values ​​to the control point 601 of the spline curve 602, the Z-direction coordinate of the control point 601 also needs to be specified, and its value can be determined by the gravity vertical line method. In the application process, a larger z value can be added to each generated simulation coordinate (x, y) to ensure that (x, y, z) is located above the ground of the simulation scene (corresponding to the simulation space range), and then a vertical line is drawn to the ground in the direction of gravity. The intersection of the vertical line and the ground is the control point 602 with the real z coordinate. Among them, the ground can be understood as the ground of the simulated three-dimensional terrain contained in the simulation space range and corresponding to the real geographical range.

[0085] In step 520, a mesh body is added between adjacent control points of the spline curve to obtain a spline mesh body.

[0086] In step 530, a simulation model of the geographic vector data to be processed is obtained based on the spline grid.

[0087] In one embodiment, a mesh body can be added between adjacent control points to generate a spline mesh body having a shape consistent with the geographic vector. Further, a simulation model of the geographic vector data to be processed can be obtained based on the spline mesh body.

[0088] Combination Figure 7It can be seen that the vector data of a lake (corresponding to the geographic vector data to be processed) can be used to assign values ​​to the control points of the spline curve. During the application process, a curve with a smooth shape can be generated, and a static mesh can be added between adjacent control points. It should be noted that for planar data, the static mesh can cover the internal enclosing area of ​​the spline curve. In another example, lake water material can also be added to the planar mesh to form a lake simulation model with better visual effects. For the formed lake simulation model, the contour of the lake surface is based on real surveying and mapping data, and the appearance conforms to the characteristics of the lake, which improves the visualization effect of the simulation model.

[0089] In yet another exemplary embodiment of the present invention, Figure 5 Taking the example as an example, before obtaining a simulation model of the geographic vector data to be processed based on the spline mesh, the geographic vector data simulation modeling method may also include: adding material effects to the spline mesh to obtain a processed spline mesh, and using the processed spline mesh as the final spline mesh, wherein the material effects match the features corresponding to the geographic coordinate sequence.

[0090] In one embodiment, the generated spline mesh can be assigned a material corresponding to the geographic vector, such as roads, pipes, water bodies, etc., and material parameters such as color, roughness, and reflectivity can be adjusted. In one example, if the geographic vector data to be processed contains more detailed attribute information, more sophisticated materials can be selected, such as asphalt roads, gravel roads, metal pipes, plastic pipes, etc., so that its visualization effect and physical properties are closer to the original vector object, and finally the simulation modeling of the geographic vector data to be processed is completed.

[0091] Combination Figure 8 It can be seen that based on the lake model established above, the lake material parameters can also be adjusted to make the lake surface have slight water waves and reflection effects. It can be clearly seen from the low-altitude perspective that the visualization effect of the lake model has become more realistic. In another example, wind and waves, buoyancy and other effects can be added to be closer to the real nature of the lake.

[0092] According to the above description, the geographic vector data simulation modeling method provided by the present invention, by performing coordinate transformation on each geographic coordinate in the geographic coordinate sequence based on geographic registration points and simulation registration points to obtain simulation coordinates, and obtaining a simulation model of the geographic vector data to be processed according to the simulation coordinates, realizes automatic simulation modeling of the geographic vector data to be processed, and generates a simulation model corresponding to the geographic vector data to be processed with high visualization effect, thereby improving the modeling efficiency in the simulation modeling process and the visualization effect of the simulation model.

[0093] Based on the same concept, the present invention also provides a geographic vector data simulation modeling device.

[0094] The geographic vector data simulation modeling device provided by the present invention is described below. The geographic vector data simulation modeling device described below and the geographic vector data simulation modeling method described above can be referenced to each other.

[0095] Fig. 9 It is a structural schematic diagram of the geographic vector data simulation modeling device provided by the present invention.

[0096] In an exemplary embodiment of the present invention, Fig. 9 It can be seen that the geographic vector data simulation modeling device can include a determination module 910, an acquisition module 920, a parsing module 930, a conversion module 940 and a processing module 950, and each module will be introduced below.

[0097] The determination module 910 can be configured to determine the real geographic scope to be simulated, and determine at least two geographic registration points within the real geographic scope to be simulated, and determine the simulation space scope based on the real geographic scope to be simulated, and determine at least two simulation registration points within the simulation space scope, wherein the simulation registration points are registered with the geographic registration points; the acquisition module 920 can be configured to acquire geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic scope to be simulated belong to the same coordinate system; the parsing module 930 can be configured to parse the geographic vector data to be processed and obtain multiple geographic coordinate sequences of the geographic vector data to be processed; the conversion module 940 can be configured to perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence based on the geographic registration points and the simulation registration points to obtain simulation coordinates; the processing module 950 can be configured to obtain a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0098] In an exemplary embodiment of the present invention, the conversion module 940 can perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates based on the geographic registration points and the simulation registration points in the following manner: determine the horizontal span of the real geographic range to be simulated, and based on the span, perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates according to the geographic registration points and the simulation registration points.

[0099] In an exemplary embodiment of the present invention, the geo-reference points may include a first geo-reference point and a second geo-reference point, and the simulation reference points may include a first simulation reference point and a second simulation reference point; the conversion module 940 may perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates based on the span according to the geo-reference points and the simulation reference points in the following manner: if the span is greater than or equal to the span threshold, the projection coordinates of the first geo-reference point are obtained based on the first geo-reference point, the projection coordinates of the second geo-reference point are obtained based on the second geo-reference point, and the projection coordinates of the geographic coordinates are obtained based on the geographic coordinates; based on the first simulation reference point, the second simulation reference point, the projection coordinates of the first geo-reference point, the projection coordinates of the second geo-reference point, and the projection coordinates of the geographic coordinates, each geographic coordinate in the geographic coordinate sequence is converted to obtain simulation coordinates.

[0100] In an exemplary embodiment of the present invention, the first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; the conversion module 940 can use the following formula to convert each geographic coordinate in the geographic coordinate sequence into a simulation coordinate based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point, and the projection coordinates of the geographic coordinates:

[0101]

[0102]

[0103] Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lonProj represents the longitude value of the projection coordinate of the geographic coordinate; startLonProj represents the longitude value of the projection coordinate of the first geographic reference point; endLonProj represents the longitude value of the projection coordinate of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; latProj represents the latitude value of the projection coordinate of the geographic coordinate; startLatProj represents the latitude value of the projection coordinate of the first geographic reference point; endLatProj represents the latitude value of the projection coordinate of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

[0104] In an exemplary embodiment of the present invention, the geographic registration points may include a first geographic registration point and a second geographic registration point, and the simulation registration points may include a first simulation registration point and a second simulation registration point; the conversion module 940 may perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence based on the span according to the geographic registration points and the simulation registration points to obtain simulation coordinates in the following manner: if the span is less than the span threshold, then based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point, perform coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates.

[0105] In an exemplary embodiment of the present invention, the first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; the conversion module 940 can use the following formula to convert each geographic coordinate in the geographic coordinate sequence based on the first simulation registration point, the second simulation registration point, the first geographic registration point, and the second geographic registration point to obtain the simulation coordinate:

[0106]

[0107]

[0108] Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lon represents the longitude value of the geographic coordinate; startLon represents the longitude value of the first geographic reference point; endLon represents the longitude value of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; lat represents the latitude value of the geographic coordinate; startLat represents the latitude value of the first geographic reference point; endLat represents the latitude value of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

[0109] In an exemplary embodiment of the present invention, the processing module 950 can obtain a simulation model of the geographic vector data to be processed based on the simulation coordinates in the following manner: process each geographic coordinate sequence to obtain a spline curve corresponding to each geographic coordinate sequence, wherein the simulation coordinates of each geographic coordinate in the geographic coordinate sequence are used as control points in the spline curve; add a grid body between adjacent control points of the spline curve to obtain a spline grid body; and obtain a simulation model of the geographic vector data to be processed based on the spline grid body.

[0110] In an exemplary embodiment of the present invention, the processing module 950 can also be configured to add material effects to the spline mesh to obtain a processed spline mesh, and use the processed spline mesh as the final spline mesh, wherein the material effects match the features corresponding to the geographic coordinate sequence.

[0111] Fig.10 An example of a physical structure diagram of an electronic device is shown in FIG. Fig.10 As shown, the electronic device may include: a processor (processor) 1010, a communication interface (Communications Interface) 1020, a memory (memory) 1030 and a communication bus 1040, wherein the processor 1010, the communication interface 1020, and the memory 1030 communicate with each other through the communication bus 1040. The processor 1010 can call the logic instructions in the memory 1030 to execute the geographic vector data simulation modeling method, which includes: determining the real geographic scope to be simulated, and determining at least two geographic registration points within the real geographic scope to be simulated; determining the simulation space scope based on the real geographic scope to be simulated, and determining at least two simulation registration points within the simulation space scope, wherein the simulation registration points are registered with the geographic registration points; obtaining the geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic scope to be simulated belong to the same coordinate system; parsing the geographic vector data to be processed to obtain multiple geographic coordinate sequences of the geographic vector data to be processed; based on the geographic registration points and the simulation registration points, performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates; and obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0112] In addition, the logic instructions in the above-mentioned memory 1030 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0113] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the geographic vector data simulation modeling method provided by the above methods, which includes: determining the real geographic scope to be simulated, and determining at least two geographic alignment points within the real geographic scope to be simulated; determining the simulation space scope based on the real geographic scope to be simulated, and determining at least two simulation alignment points within the simulation space scope, wherein the simulation alignment points are aligned with the geographic alignment points; obtaining the geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic scope to be simulated belong to the same coordinate system; parsing the geographic vector data to be processed to obtain multiple geographic coordinate sequences of the geographic vector data to be processed; based on the geographic alignment points and the simulation alignment points, performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates; and obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0114] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the geographic vector data simulation modeling method provided by the above-mentioned methods, the method comprising: determining a real geographic scope to be simulated, and determining at least two geographic registration points within the real geographic scope to be simulated; determining a simulation space scope based on the real geographic scope to be simulated, and determining at least two simulation registration points within the simulation space scope, wherein the simulation registration points are registered with the geographic registration points; obtaining geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic scope to be simulated belong to the same coordinate system; parsing the geographic vector data to be processed to obtain multiple geographic coordinate sequences of the geographic vector data to be processed; based on the geographic registration points and the simulation registration points, performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain simulation coordinates; and obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates.

[0115] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0116] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0117] It is further understood that, although the operations are described in a specific order in the accompanying drawings in the embodiments of the present invention, it should not be understood as requiring the operations to be performed in the specific order or serial order shown, or requiring the execution of all the operations shown to obtain the desired results. In certain environments, multitasking and parallel processing may be advantageous.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A geographic vector data simulation modeling method, characterized in that: The method comprises: Determine a real geographical range to be simulated, and determine at least two geographical registration points within the real geographical range to be simulated; Determine a simulation space range based on the real geographic range to be simulated, and determine at least two simulation registration points within the simulation space range, wherein the simulation registration points are registered with the geographic registration points; Acquire geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system; Parsing the geographic vector data to be processed to obtain a plurality of geographic coordinate sequences of the geographic vector data to be processed; Based on the geographic registration point and the simulation registration point, coordinate conversion is performed on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate; The method of obtaining a simulation model of the geographic vector data to be processed based on the simulation coordinates specifically includes: Processing each of the geographic coordinate sequences to obtain a spline curve corresponding to each of the geographic coordinate sequences, wherein the simulated coordinates of each of the geographic coordinates in the geographic coordinate sequence are used as control points in the spline curve; Adding a mesh body between adjacent control points of the spline curve to obtain a spline mesh body; A simulation model of the geographic vector data to be processed is obtained based on the spline grid.

2. The geographic vector data simulation modeling method according to claim 1, characterized in that: The step of performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the geographic registration point and the simulation registration point specifically includes: The horizontal span of the real geographic range to be simulated is determined, and based on the span, each geographic coordinate in the geographic coordinate sequence is transformed according to the geographic registration point and the simulation registration point to obtain a simulation coordinate.

3. The geographic vector data simulation modeling method according to claim 2, characterized in that: The geo-reference points include a first geo-reference point and a second geo-reference point, and the simulation reference points include a first simulation reference point and a second simulation reference point; The step of performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the span according to the geographic registration point and the simulation registration point specifically includes: If the span is greater than or equal to a span threshold, obtaining the projected coordinates of the first geo-referenced point based on the first geo-referenced point, obtaining the projected coordinates of the second geo-referenced point based on the second geo-referenced point, and obtaining the projected coordinates of the geo-coordinate based on the geo-coordinate; Based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point and the projection coordinates of the geographic coordinates, each geographic coordinate in the geographic coordinate sequence is converted into a simulation coordinate.

4. The geographic vector data simulation modeling method according to claim 3, characterized in that: The first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; The coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate based on the first simulation registration point, the second simulation registration point, the projection coordinates of the first geographic registration point, the projection coordinates of the second geographic registration point and the projection coordinates of the geographic coordinate is implemented by the following formula: Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lonProj represents the longitude value of the projection coordinate of the geographic coordinate; startLonProj represents the longitude value of the projection coordinate of the first geographic reference point; endLonProj represents the longitude value of the projection coordinate of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; latProj represents the latitude value of the projection coordinate of the geographic coordinate; startLatProj represents the latitude value of the projection coordinate of the first geographic reference point; endLatProj represents the latitude value of the projection coordinate of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

5. The geographic vector data simulation modeling method according to claim 2, characterized in that: The geo-reference points include a first geo-reference point and a second geo-reference point, and the simulation reference points include a first simulation reference point and a second simulation reference point; The step of performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the span according to the geographic registration point and the simulation registration point specifically includes: If the span is less than the span threshold, based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point, coordinate transformation is performed on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate.

6. The geographic vector data simulation modeling method according to claim 5, characterized in that: The first geographic registration point is registered with the first simulation registration point, and the second geographic registration point is registered with the second simulation registration point; The coordinate conversion of each geographic coordinate in the geographic coordinate sequence to obtain the simulation coordinate based on the first simulation registration point, the second simulation registration point, the first geographic registration point and the second geographic registration point is implemented by the following formula: Among them, x represents the horizontal coordinate of the simulation coordinate; y represents the vertical coordinate of the simulation coordinate; lon represents the longitude value of the geographic coordinate; startLon represents the longitude value of the first geographic reference point; endLon represents the longitude value of the second geographic reference point; endX represents the horizontal coordinate of the second simulation reference point; startX represents the horizontal coordinate of the first simulation reference point; lat represents the latitude value of the geographic coordinate; startLat represents the latitude value of the first geographic reference point; endLat represents the latitude value of the second geographic reference point; endY represents the vertical coordinate of the second simulation reference point; startY represents the vertical coordinate of the first simulation reference point.

7. The geographic vector data simulation modeling method according to claim 1, characterized in that: Before obtaining the simulation model of the geographic vector data to be processed based on the spline grid body, the method further includes: A material effect is added to the spline mesh to obtain a processed spline mesh, and the processed spline mesh is used as a final spline mesh, wherein the material effect matches the land feature corresponding to the geographic coordinate sequence.

8. A geographic vector data simulation modeling device, characterized in that: The device is used to implement the geographic vector data simulation modeling method according to any one of claims 1 to 7, and the device comprises: A determination module, used to determine a real geographic range to be simulated, and determine at least two geographic registration points within the real geographic range to be simulated, and to determine a simulation space range based on the real geographic range to be simulated, and determine at least two simulation registration points within the simulation space range, wherein the simulation registration points are set in registration with the geographic registration points; An acquisition module, used for acquiring geographic vector data to be processed, wherein the geographic vector data to be processed and the real geographic range to be simulated belong to the same coordinate system; A parsing module, used for parsing the geographic vector data to be processed to obtain a plurality of geographic coordinate sequences of the geographic vector data to be processed; A conversion module, used for performing coordinate conversion on each geographic coordinate in the geographic coordinate sequence to obtain a simulation coordinate based on the geographic registration point and the simulation registration point; A processing module is used to obtain a simulation model of the geographic vector data to be processed based on the simulation coordinates.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the geographic vector data simulation modeling method as described in any one of claims 1 to 7 is implemented.

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