Three-dimensional virtual ecological environmental visualization integration and optimization system for large region

Abstract

A three-dimensional (3D) virtual ecological environmental visualization system for large regions comprises: a construction unit 201, a logical chunk unit 202, and a visualization unit 203. The constru

Description

Background Field of the Invention The present application relates to the technical field of virtual environmental visualization, and in particular to a three-dimensional virtual ecological environmental visualization integration and optimization system for large region. Background Information The three-dimensional virtual ecological environmental relates to the data from various sources such as terrain, remote sensing image, temperature and the like, which has the characteristics of complex structure and a large amount of data. The large amount of data and complex data structure have become the bottleneck of the three-dimensional virtual ecological environmental visualization. In the related technologies, in order to handle a large amount of heterogeneous ecological environmental data so as to construct the three-dimensional virtual ecological environmental with high resolution in large region (such as thousands of kilometers range), the three-dimensional GIS engines developed by various geographic information system (GIS) manufacturers are usually used to handle these ecological environmental data, and then the model, texture and other characteristics of the game engine (such as Unity3D) are integrated to enhance the realism of the three-dimensional virtual ecological environmental, the scene of the three-dimensional virtual environment is more clearly reflected from the aspects of texture, material and the like, so as to obtain the better realism experience. However, due to the implementation principle and rendering method of the threedimensional GIS engine is different from the game engine, it is still difficult to achieve the realistic effect in game engine by introducing some characteristics of the game engine into the threedimensional GIS engine. In other related technologies, there are also a technical solutions that integrate the GIS data by game engine importing the ecological environmental data into the game engine, so as to ensure the realistic effect in game engine and achieve the visualization of the three-dimensional virtual ecological environmental. However, the scene in game engine is usually fictional scene, and the range of scene can be expressed is usually small, which cannot handle the large amount of heterogeneous ecological environmental data with high resolution in large region of the real world, and it is difficult to achieve the visualization of high realistic three-dimensional virtual ecological environmental with high resolution in large region. Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art. SUMMARY It is an object of the present application to provide a three-dimensional virtual ecological environmental visualization integration and optimization system for large region to solve or alleviate the above-mentioned problems in the prior art. In order to achieve the above-mentioned object, the present application provides the following technical solutions: the present application provides a three-dimensional virtual ecological environmental visualization integration and optimization system for large region which comprises: a construction unit, a logical chunk unit and a visualization unit; the construction unit is used to construct a three-dimensional virtual ecological environmental model corresponding to an ecological environmental data, and a plurality of model hierarchies corresponding to a scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to the ecological environmental data and a digital elevation model of an object region; wherein, the scene assembly is a scene assembly in a game engine, and the ecological environmental data have a plurality of types, which are a data from different sources and have different data structures; the logical chunk unit is used to perform logical separation on the model hierarchy to obtain a plurality of logical chunks corresponding to each model hierarchy, and a mapping relationship between a three-dimensional coordinate and a geographic coordinate of each logical chunk according to the geographic coordinate of the ecological environmental data and the threedimensional coordinate of each model hierarchy in the plurality of model hierarchies; wherein, the logical chunk is corresponded to each scene in the scene assembly of the three-dimensional virtual ecological environmental; the visualization unit is used to visualize the scene assembly of the three-dimensional virtual ecological environmental based on the plurality of logical chunks and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk. Preferable, the construction unit comprises a triangle network construction module, a texture mapping module and a data hierarchy module; the triangle network construction module is used to establish a plane triangle network model of the object region, and determine an elevation of each triangle vertex in the plane triangle network model to obtain a three-dimensional triangle network model according to the digital elevation model; the texture mapping module is used to map the ecological environmental data as a texture onto the three-dimensional triangle network model to obtain the three-dimensional virtual ecological environmental model corresponding to the ecological environmental data; the data hierarchy module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to different display accuracies. Preferable, the data hierarchy module comprises a first hierarchy sub-module and a second hierarchy sub-module; the first hierarchy sub-module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain a plurality of model hierarchies with different resolutions corresponding to the ecological environmental data according to the different resolutions, when the three-dimensional virtual ecological environmental model is a three-dimensional terrain model; wherein, the model hierarchy with each resolution is corresponded to each scene assembly; the second hierarchy sub-module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain a plurality of model hierarchies with different feature quantities corresponding to the ecological environmental data according to the feature quantity in the threedimensional virtual ecological environmental model, when the three-dimensional virtual ecological environmental model is a feature model; wherein, each model hierarchy is corresponded to each scene assembly. Preferable, the construction unit also comprises a spatio-temporal dynamic data construction module; the spatio-temporal dynamic data construction module is used to sample the ecological environmental data at a preset time interval to obtain a plurality of dynamic images, and map the dynamic image as a texture onto the plane triangle network model to obtain a three-dimensional virtual ecological environmental model of spatio-temporal dynamic according to a temporal order. Preferable, the visualization unit comprises a loading module and a dynamic update module; the loading module is used to obtain N x N adjacent logical chunks, and load the scene assembly based on the N x N adjacent logical chunks; wherein, N is an integer greater than or equal to 1; the dynamic update module is used to update the scene assembly based on a distance between a search point and a target location point in a scene of the three-dimensional virtual ecological environmental. Preferable, the dynamic update module comprises a first update sub-module and a second update sub-module; the first update sub-module is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different resolutions according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the three-dimensional terrain model; the second update sub-module is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different feature quantities according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the feature model. Preferable, the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a first resolution, when the distance between the search point and the target location point is greater than a first distance threshold; the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a second resolution, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than a second distance threshold; the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a third resolution, when the distance between the search point and the target location point is less than or equal to the second distance threshold; wherein, the first distance threshold is greater than the second distance threshold, and the first resolution, the second resolution, and the third resolution are increased sequentially; the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a feature quantity which is greater than a first feature size, when the distance between the search point and the target location point is greater than the first distance threshold; the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the first feature size and greater than a second feature size, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than the second distance threshold; the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the second feature size, when the distance between the search point and the target location point is less than or equal to the second distance threshold; wherein, the first feature size is greater than the second feature size. Preferable, the visualization unit further comprises an interactive augmentation module; the interactive augmentation module is used to set a visualization display strategy of the model hierarchy, according to the plurality of model hierarchies with different accuracies corresponding to the ecological environmental data. Preferable, the system further comprises a virtual reality module which is used to perform immersive exploration on the three-dimensional virtual ecological environmental based on a virtual reality technology. Advantageous effects: The three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided by the present application comprises: a construction unit, a logical chunk unit and a visualization unit; wherein, the construction unit is used to construct a three-dimensional virtual ecological environmental model corresponding to an ecological environmental data, and a plurality of model hierarchies corresponding to a scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to the ecological environmental data and a digital elevation model of an object region; the logical chunk unit is used to perform logical separation on the model hierarchy to obtain a plurality of logical chunks corresponding to each model hierarchy, and a mapping relationship between a three-dimensional coordinate and a geographic coordinate of each logical chunk according to the geographic coordinate of the ecological environmental data and the threedimensional coordinate of each model hierarchy in the plurality of model hierarchies; wherein, the logical chunk is corresponded to each scene in the scene assembly of the three-dimensional virtual ecological environmental; the visualization unit is used to visualize the scene assembly of the threedimensional virtual ecological environmental based on the plurality of logical chunks and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk. In this way, during the construction process of model, the scene assembly required for different display accuracies of three-dimensional virtual ecological environmental model of large region is constructed through the construction unit to improve the visualization efficiency of scene assembly of three-dimensional virtual ecological environmental model of large region in game engine; Through the logical chunk unit, the model hierarchy is separated into the plurality of logical chunks to achieve logical segmentation of large region, and each logical chunk or the combination of the plurality of logical chunks is the scene range that the game engine can handle, and the corresponding relationship between logical chunks and each scene in scene assembly is established to index each logical chunk during the visualization process, so as to achieve high realism and efficiency visualization of the three-dimensional virtual ecological environmental of large region. BRIEF DESCRIPTION OF THE DRAWINGS The drawings forming a part of the present application are used to provide a further understanding of the present application. The illustrative examples and explanations of the present application are used to explain the present application and do not constitute an improper limitation of the present application. Wherein: Fig. 1 is a logical schematic diagram of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application; Fig. 2 is a structural schematic diagram of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application; Fig. 3 is a structural schematic diagram of the construction unit of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application; Fig. 4 is a structural schematic diagram of the data hierarchy module of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application; Fig. 5 is a structural schematic diagram of the visualization unit of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application; Fig. 6 is a structural schematic diagram of the dynamic update module of the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided according to some examples of the present application. DETAILED DESCRIPTION OF EMBODIMENTS The present application will be explained in detail below with reference to the drawings and in conjunction with examples. Each example is provided through the interpretation of the present application rather than limiting it. In fact, those skilled in the art will be aware that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. For example,the characteristics shown or described as part of one example may be used in another example to generate another example. Therefore, it is expected that the present application comprises such modifications and variations within the scope of the attached claims and their equivalents. In the early days, due to the limitation of computer software and hardware technology, it was difficult to generate a highly realistic three-dimensional virtual ecological environmental and to support intelligent high-performance computing, so it was difficult to establish and apply the threedimensional virtual ecological environmental system to achieve accurate management and decisionmaking of the ecological environment. In recent years, with the development of computer software and hardware technology, the software technologies related to three-dimensional virtual reality based on high-performance graphics processing unit (GPU) technology, especially game engine technology have rapidly been developed to provide a technical foundation for the establishment of the three-dimensional virtual ecological environmental. However, as described in the background technology, the three-dimensional virtual ecological environmental established based on the game engine cannot handle the situation of large amount of heterogeneous ecological environmental data with high resolution in large region. The present application provides a three-dimensional virtual ecological environmental visualization integration and optimization system for large region, which combines the virtual reality technology with the ecological environment information system to create a highly realistic ecological environment for large region of thousands of kilometers range, the real scene is visually and vividly presented. This system can promote interdisciplinary communication and exchange among relevant personnel, so as to present an immersive and intelligent decision-making environment for ecological environment decision-maker, which will be great significance for research in various fields such as climate change, carbon emissions, floods and other natural disasters, and ecological environment governance. The example of the present application provides a three-dimensional virtual ecological environmental visualization integration and optimization system for large region, as shown in Figs. 1-6, this system comprises: the construction unit 201, the logical chunk unit 202 and the visualization unit 203. Wherein, the construction unit 201 is used to construct the three-dimensional virtual ecological environmental model corresponding to an ecological environmental data, and the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the threedimensional virtual ecological environmental model according to the ecological environmental data and the digital elevation model of an object region; wherein, the scene assembly is the scene assembly in the game engine, and the ecological environmental data have the plurality of types, which are the data from different sources and have different data structures. In the example of the present application, the object region is large region. Here, the large region refers to an range which is greater than 1000 square kilometers. In the example of the present application, the three-dimensional virtual ecological environmental model corresponding to an ecological environmental data is constructed according to the ecological environmental data and the digital elevation model of an object region, and the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the threedimensional virtual ecological environmental model are constructed based on the three-dimensional virtual ecological environmental model, so as to achieve the big data management strategy of hierarchy and chunk for large region. In the example of the present application, the scene assembly is a scene assembly in the game engine. The multi-source heterogeneous ecological environmental data is modeled to obtain the three-dimensional virtual ecological environmental model, each type of ecological environmental data is corresponded to one or more model hierarchies, and it is visualized based on the game engine, and can achieve efficient visualization of the three-dimensional virtual ecological environmental with high resolution in large region and improve the realism of the three-dimensional virtual ecological environmental. Here, the game engine can be a Unity3D or UE4 (RTM) engine. The following is a detailed explanation of the technical solution implemented in present application by using Unity 3D as an example. It should be noted that the ecological environmental data have a plurality of types, which are data from different sources and have different data structures. Specifically, for constructing the threedimensional virtual ecological environmental model, it comprises the data from different sources such as the geographic data, the climate data, and the simulation data and the like. In terms of data structure, the above data can be a raster data or a vector data. Wherein, the raster data is a data form that separates the space into regular grids, each of which is called a unit, and assigns corresponding attribute values to each unit to represent the geographic entities. The position of each unit (pixel) is defined by its row and column number, and the geographic entity position represented is implied in the grid row and column position, and each data in the data organization represents the non geometric attributes of a feature or phenomenon or a pointer to its attributes. Vector data is a data that represents the position and shape of map graphics or geographical entities in rectangular coordinate by using x, y coordinates. Vector data generally represents the spatial location of geographical entities as accurately as possible by recording coordinates, while reducing the storage space occupied by the data. Geographic data refers to the data which describes the natural, social and cultural landscape with the reference to the spatial position of the earth's surface. It is a data directly or indirectly related to a place relative to the earth, and is a element files representing the natural and social phenomenon of geographical location and distribution characteristics, which includes natural geographical data and socio-economic data. Wherein, geographic data includes digital elevation model (DEM). DEM is one of the raster data, which achieves the digital simulation of ground terrain (i.e. the digital expression of terrain surface morphology) through limited terrain elevation data. It is a solid ground model that represents the ground elevation in an ordered numerical array form, and each unit value in DEM represents the ground height of this point. In the example of the present application, the DEM data or the DEM of the object region which are generated by other methods can be obtained through the Shuttle Radar Topography Mission (SRTM). Geographic data also includes Remote Sensing Image (RS) data, which is another raster data, and is a earth digital image obtained through remote sensing form. It can also be understood as a photo taken of the Earth. In the example of the present application, a remote sensing image with high resolution is used as the texture of DEM to establish three-dimensional terrain model. Here, the resolution can be either spatial resolution or temporal resolution. When the resolution is spatial resolution, high resolution refers to the remote sensing image with the spatial resolution which is greater than 0.5 meters. When resolution is temporal resolution, high resolution refers to the remote sensing image with the data collection interval which is less than 10 days. In the example of the present application, climate data may be the data that reflects weather, such as the data obtained from various meteorological observation stations or relevant departments (such as the National Meteorological Information Center). Wherein, the climate data obtained from various meteorological observation stations is usually vector data, and each meteorological observation station is one point in the vector data. During the construction process of threedimensional virtual ecological environmental model, one point in the vector data is represented by one feature model. The climate data obtained from relevant departments may also be raster data. In this case, climate data can be used as the texture of DEM to construct the three-dimensional climate model of different terrains in the three-dimensional virtual ecological environmental model. In the example of the present application, simulation data is the data generated through computer simulation or algorithm, rather than the data generated from real data, such as climate or meteorological simulation. That is to say, simulation data is the data created in the digital world, rather than the data collected or measured from the real world. Simulation data is based on real-life data to simulate the future ecological environment, which can be integrated into the threedimensional virtual ecological environmental system to achieve the prediction of the ecological environment system within the certain time range. When the simulation data is raster data, it can be used as the texture of DEM to construct simulation model under different terrains in the threedimensional virtual ecological environmental model; When the simulation data is vector data, the model for each vector object is established and the feature model corresponding to each vector object is obtain. In practical applications, in order to construct the three-dimensional virtual ecological environmental model based on the aforementioned multi-source heterogeneous ecological environmental data and DEM, it is necessary to unify the spatial coordinate system of the aforementioned multi-source heterogeneous ecological environmental data and DEM, firstly. In the example of the present application, geographic information system (GIS) software, such as ArcGIS (RTM) or QGIS (RTM) and the like, can be used to perform the operation for unifying spatial coordinate system for multi-source heterogeneous ecological environmental data and DEM. In the example of the present application, the construction unit 201 imports the plurality of ecological environmental data, unifies the coordinate system, establishes the three-dimensional virtual ecological environmental model, and performs model hierarchy on them, thereby achieving the hierarchy management of the multi-source ecological environmental data. It should be understood that when handling the small regions (i.e. other regions whose region scope is smaller than that of the above large region), the three-dimensional virtual ecological environmental model corresponding to ecological environmental data can be constructed, and then the three-dimensional virtual ecological environmental model is corresponded to one model hierarchy, without the need to implement the big data management strategies of hierarchy and chunk. In some examples, in order to construct the three-dimensional virtual ecological environmental model corresponding to the ecological environmental data, the triangle network construction module 301, the texture mapping module 302 and the data hierarchy module 303 are disposed in the construction unit 201. Wherein, the triangle network construction module 301 is used to establish the plane triangle network model of the object region, and determine an elevation of each triangle vertex in the plane triangle network model to obtain the three-dimensional triangle network model according to the digital elevation model; the texture mapping module 302 is used to map the ecological environmental data as the texture onto the three-dimensional triangle network model to obtain the three-dimensional virtual ecological environmental model corresponding to the ecological environmental data; the data hierarchy module 303 is used to hierarchize the threedimensional virtual ecological environmental model to obtain the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to different display accuracies. In this way, the corresponding three-dimensional virtual ecological environmental model constructed from the ecological environmental data is achieved, and the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the threedimensional virtual ecological environmental model are obtained, through the triangle network construction module 301, the triangle network construction module 302 and the data hierarchy module 303. The following is a detailed explanation of the example of present application, by remote sensing image data and DEM to construct the three-dimensional terrain model. In specific applications, the triangle network construction module 301 firstly uses the Delaunay method to establish the plane triangle network model of the object region according to the boundary of the object region, and determines the elevation of each triangle vertex in the plane triangle network model to obtain the three-dimensional triangle network model according to the digital elevation model DEM. Here, based on DEM, the triangle vertex of the plane corresponding to the triangle network model can be added with corresponding elevation to generate the DEM threedimensional triangle network model. The texture mapping module 302 establishes the mapping relationship between the DEM three-dimensional triangle network model and high-definition and high-resolution remote sensing image, and then maps the high-definition and high-resolution remote sensing image as the texture onto the DEM three-dimensional triangle network model to obtain the three-dimensional virtual ecological environmental model corresponding to the ecological environmental data, namely the three-dimensional terrain model. Then, the data hierarchy module 303 hierarchizes the three-dimensional terrain model to obtain the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the three-dimensional terrain model according to different display accuracies. Finally, the three-dimensional terrain model is formatted, and the three-dimensional terrain model is converted to the universal three-dimensional model format. Taking Unity3D as an example, the universal three-dimensional model format of Unity3D is usually FBX format, which converts the three-dimensional terrain model to FBX format and imports it into Unity3D. By using the construction unit 201, the three-dimensional virtual ecological environmental model is constructed on other heterogeneous ecological environmental data to be integrated from different sources, and model hierarchy is performed, with each model hierarchy serving as one hierarchical game object for Unity3D. In some examples, the data hierarchy module 303 comprises a first hierarchy sub-module 401 and a second hierarchy sub-module 402 when the three-dimensional terrain model is hierarchized according to different display accuracies. Wherein, the first hierarchy sub-module 401 is used to hierarchize the three-dimensional virtual ecological environmental model to obtain the plurality of model hierarchies with different resolutions corresponding to the ecological environmental data according to the different resolutions, when the three-dimensional virtual ecological environmental model is the three-dimensional terrain model; wherein, the model hierarchy with each resolution is corresponded to each scene assembly; the second hierarchy sub-module 402 is used to hierarchize the three-dimensional virtual ecological environmental model to obtain the plurality of model hierarchies with different feature quantities corresponding to the ecological environmental data according to the feature quantity in the three-dimensional virtual ecological environmental model, when the three-dimensional virtual ecological environmental model is the feature model; wherein, each model hierarchy is corresponded to each scene assembly. In the example of the present application, when the three-dimensional virtual ecological environmental model is the three-dimensional terrain model, for the the three-dimensional terrain model of large region (or other spatial models which is similar to the three-dimensional terrain model), the first hierarchy sub-module 401 hierarchizes the three-dimensional terrain model to obtain the plurality of model hierarchies with different resolutions corresponding to the ecological environmental data according to the different resolutions, the model hierarchy with each resolution is corresponded to each scene assembly. Therefore, during the visualization process, the plurality of model versions with different resolutions are prepared for three-dimensional virtual ecological environmental model based on different display resolution requirements, which improve visualization efficiency and ensure the smooth transition of visual effects, while maximizing the overall performance of the system and ensuring the visualization efficiency. When the three-dimensional virtual ecological environmental model is the feature model, the second hierarchy sub-module 402 firstly determines the number of features in the feature model. When there are the plurality of features, the features are classified according to feature quantity in the three-dimensional virtual ecological environmental model, thus separating the features into the plurality of feature types based on their quantity; then, based on the type of each feature in the feature model, the feature model is hierarchized to obtain the plurality of model hierarchies with different feature quantities corresponding to the ecological environmental data. Wherein, each model hierarchy corresponding to each feature quantity is corresponded to each scene assembly. It should be noted that, in the example of the present application, when the three-dimensional virtual ecological environmental model is hierarchized, the different resolutions or different feature quantities used can be specifically set according to the quantity of object region and different display quality requirements, or can be set by preset system parameters according to the prior knowledge. It can be understood that when there is only one feature in the feature model, this feature model is not classified. In this case, the feature model has only one model hierarchy, which is itself. In the example of the present application, the data hierarchy module 303 is also used to sort each model hierarchy according to resolution from large to small or feature quantity from large to small, so as to facilitate real-time loading of model hierarchy during subsequent visualization. In some examples, the ecological environmental data also comprises the spatio-temporal dynamic data, and in this case, the construction unit 201 also comprises the spatio-temporal dynamic data construction module; the spatio-temporal dynamic data construction module is used to sample the ecological environmental data at the preset time interval to obtain the plurality of dynamic images, and map the dynamic image as the texture onto the plane triangle network model to obtain the threedimensional virtual ecological environmental model of spatio-temporal dynamic according to the temporal order. In the example of present application, the spatio-temporal data refers to the image with temporal and spatial information used to express ecological environment information. In specific applications, the spatio-temporal dynamic data construction module samples the ecological environmental data at the preset time interval to obtain the plurality of dynamic images, then, the mapping relationship between the plurality of dynamic images and the texture of the three dimensional triangle network model is established according to temporal order, and during subsequent visualization, the dynamic image is loaded based on the texture mapping relationship between the plurality of dynamic images and the three-dimensional triangle network model, to form the dynamic rendering effect. The logical chunk unit 202 is used to perform logical separation on the model hierarchy to obtain the plurality of logical chunks corresponding to each model hierarchy, and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk according to the geographic coordinate of the ecological environmental data and the threedimensional coordinate of each model hierarchy in the plurality of model hierarchies; wherein, the logical chunk is corresponded to each scene in the scene assembly of the three-dimensional virtual ecological environmental. In the example of the present application, the quantity of each logical chunk can be a predetermined chunk quantity. By performing logical separation on the three-dimensional virtual ecological environmental model of large region, the efficient access to the three-dimensional virtual ecological environmental model of large region model scene can be ensured. In the example of the present application, the ecological environmental data and the threedimensional coordinate in the game engine are different coordinate systems, the logical chunk obtains the corresponding relationship between the geographic coordinate of the ecological environmental data and the three-dimensional coordinate of each model hierarchy while performing logical separation on model hierarchy. Specifically, the coordinate system of the ecological environmental data is geographic coordinate longitude and latitude, and each model hierarchy uses three-dimensional coordinate of Unity3D, when performing logical separation on the model hierarchy, the mapping relationship between the three-dimensional coordinate and the geographic coordinate of the logical chunk is established. Wherein, WGS84 Web Mercator projection is used from geographic coordinate to plane coordinate projection, so as to flexibly support the plurality of indexing access methods. In practical applications, DEM data and high-definition and high-resolution resolution remote sensing image data are obtained by the geographic coordinate of the object region. WGS84 Web Mercator projection is used to convert the coordinate system of DEM data and remote sensing image data into plane coordinate projection, and then, the mapping of high-definition and high-resolution remote sensing image and DEM are established according to the predetermined chunk quantity, as a texture, the remote sensing image is added to DEM, and the high-definition three-dimensional terrain model of logical chunk for large region is established. It should be understood that for other ecological environmental data except the terrain, such as temperature, precipitation, etc., various multi-source heterogeneous ecological environmental data can be handled according to the aforementioned steps by replacing DEM with other spatial data and replacing remote sensing image data with corresponding texture data of other ecological environmental data, and the corresponding three-dimensional virtual ecological environmental model and the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of this three-dimensional virtual ecological environmental model are generated. In the example of the present application, the logical chunk is correspond to each scene in the scene assembly of the three-dimensional virtual ecological environmental. Taking Unity3D as an example, Unity3D can efficiently load or unload the scene, while loading or unloading the game object which it contains. Each model hierarchy is corresponded to the plurality of logical chunks, and each logical chunk is associated with each scene of Unity3D, one scene assembly is composed of the plurality of scenes corresponding to the plurality of logical chunks of same model hierarchy. It should be noted that the logical separation of model hierarchy in the present application is different from the traditional separation method. The traditional separation method is to physically separate the model hierarchy, that is, the traditional separation method separates model hierarchy into the plurality of physically independent chunks. In the present application, logical separation for model hierarchy of large region is not a true physical segmentation, but rather establishes the associations between each logical chunk and the corresponding scene according to the organization mode of the logical chunk of the three-dimensional virtual ecological environmental model of large region, and records the corresponding association information in scene assembly. For the traditional game engine, such as Unity3D, when modeling the ecological data, the obtained three-dimensional virtual ecological model is usually a whole in the physical storage, for example, it is stored as the FBX format of Unity3D, so the generated three-dimensional virtual ecological model is extremely limited in the region scope, and Unity3D can not support the modeling of the three-dimensional virtual ecological environment of large region due to the optimization of hierarchical details and the support defects of large region modeling. The three dimensional virtual ecological environmental visualization integration and optimization system for large region provided by the present application can generate a three-dimensional virtual ecological environmental model with a high realistic for a small region obtained after chunking by delaminating and chunking the three-dimensional virtual ecological environmental model of large region and adopting the big data management strategy of hierarchy and chunk, so as to solve the problem of the high realistic of the three-dimensional virtual ecological environment, and at the same time, efficiently and smoothly support the exploration, simulation and real-time monitoring of big data, and achieve the integration of multi-source heterogeneous ecological data and the display of the three-dimensional virtual environment, to sufficiently handle and optimize the visualization effect and browsing performance. The visualization unit 203 is used to visualize the scene assembly of the three-dimensional virtual ecological environmental based on the plurality of logical chunks and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk. In the example of the present application, the visualization unit 203 obtains the plurality of scene assembly corresponding to the plurality of logical chunks through a preset visualization data model based on the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk, so as to efficiently and realistically visualize the scene assembly of three-dimensional virtual ecological environmental. When the big data three-dimensional virtual ecological environmental model organized by the scene and scene assembly are visualized, in some examples, the visualization unit 203 comprises the loading module 501 and the dynamic update module 502. Wherein, the loading module 501 is used to obtain N * N adjacent logical chunks, and load the scene assembly based on the N * N adjacent logical chunks; wherein, N is an integer greater than or equal to 1. The dynamic update module 502 is used to update the scene assembly based on the distance between the search point and the target location point in the scene of the three-dimensional virtual ecological environmental. Taking Unity3D as an example, when visualizing big data organized by scene and scene assembly, for each scene assembly, the loading module 501 obtains N * N adjacent logical chunks, wherein, N x N can be any mode among the 3 x 3 adjacent logical chunks, the 4 * 4 adjacent logical chunks, and the 5 x 5 adjacent logical chunks. N x N adjacent logical chunks are loaded and then rendered to obtain the scene assembly corresponding to the current search point. When the position of the search point changes or the parameters related to the visualization changes, the dynamic update module 502 utilizes the dynamic loading and unloading characteristics of Unity3D to unload or reload the scene in real-time according to the distance, thereby updating the scene assembly. In some examples, in order to update scene assembly, the dynamic update module 502 comprises the first update sub-module 601 and the second update sub-module 602. Wherein, the first update sub-module 601 is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different resolutions according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the three-dimensional terrain model. The second update sub-module 602 is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different feature quantities according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the feature model. Specifically, when the three-dimensional virtual ecological environmental model is the threedimensional terrain model, for the plurality of model hierarchies of the three-dimensional terrain model, according to the principle of multi-hierarchy loading, if there are many different resolutions, according to the distance between the search point and the target location point, loading high-quality scene in the short distance and loading low-quality scene in the far distance. If there are features with different quantities, the principle of loading high-quality scene in the short distance and loading low-quality scene in the far distance should be followed to optimize visual effects while maintaining visualization efficiency. In order to achieve satisfactory visual effects, in some examples, the first update sub-module 601 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the first resolution, when the distance between the search point and the target location point is greater than the first distance threshold; the first update sub-module 601 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the second resolution, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than the second distance threshold; the first update sub-module 601 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the third resolution, when the distance between the search point and the target location point is less than or equal to the second distance threshold; wherein, the first distance threshold is greater than the second distance threshold, and the first resolution, the second resolution, and the third resolution are increased sequentially. The second update sub-module 602 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is greater than the first feature size, when the distance between the search point and the target location point is greater than the first distance threshold; the second update sub-module 602 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the first feature size and greater than the second feature size, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than the second distance threshold; the second update submodule 602 is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the second feature size, when the distance between the search point and the target location point is less than or equal to the second distance threshold; wherein, the first feature size is greater than the second feature size. In specific applications, dis.short, dis.far are used to represent the second distance threshold (short distance length) and the first distance threshold (far distance length), respectively; lod.near, lod.far are used to represent the resolution used at short distance and the detailed resolution used at far distance, respectively, lod.small, lod.big represent the detailed model resolution used for loaded and displayed small features at short distance (second feature size) and the detailed model resolution used for loaded and displayed large features at far distance (second feature size). A data model, which can be visualization displayed simultaneously, can be established as follows: dis.short * lod.near + dis.far * lod.far + dis.short * lod.small + dis.far * lod.big Based on the visualization displayed data model shown in the above equation, the visualization effect is optimized by adjusting different resolutions (or feature quantities) and corresponding distance lengths to achieve satisfactory visual effect. In the example of the present application, in view of the situation that Unity3D is inefficient or does not support the large-scale three-dimensional model visualization, an efficient big data visualization model management strategy suitable for Unity3D is designed based on Unity3D Scene, thus improving the visualization effect of the three-dimensional virtual ecological environmental. In some examples, the visualization unit 203 further comprises an interactive augmentation module; the interactive augmentation module is used to set the visualization display strategy of the model hierarchy, according to the plurality of model hierarchies with different accuracies corresponding to the ecological environmental data. In practical applications, due to the model hierarchy is an independent storey in Unity3D, the scripts can be written to achieve the exploration and display of the model hierarchy, the setting of the search point (view point) and exploration path, and the setting of the spatio-temporal dynamic data display control. Specifically, the visualization display strategy of the model hierarchy comprises at least one of the following: 1) Setting the model hierarchy in the three-dimensional virtual ecological environmental model to be visualized according to the big data management strategy of hierarchy and chunk of large region. 2) Setting the key region or the interest point during the visualization process. Wherein, the key region is the region that have a significant impact on decision-making related to the ecological environment in the object region. 3) Setting the exploration path of the three-dimensional virtual ecological environmental. 4) Setting the display method of the spatio-temporal dynamic data, for example, achieving the visualization the spatio-temporal dynamic model in a cyclic manner by writing scripts in Unity3D. By setting the visualization display strategy of the model hierarchy, the exploration and simulation experience of the three-dimensional virtual ecological environmental can be achieved according to the set manner. In some examples, the system further comprises the virtual reality module which is used to perform immersive exploration on the three-dimensional virtual ecological environmental based on the virtual reality technology. Taking Unity3D as an example, based on MiddleVR technology, immersive ecological environment exploration is carried out by using headband three-dimensional display device or the virtual reality devices such as stereoscopic glasses and electronic gun, thereby improving the interaction ability of Unity3D and increasing the user's realistic experience. In the example of the present application, MiddleVR technology is introduced into game engine Unity3D to support users to operate (such as roam) the established three-dimensional virtual ecological environmental through 3D glasses, helmets, and other sensing devices, so as to achieve a high degree of immersion in augmented reality. During the specific implementation, the implementation process of the exploration of the threedimensional virtual ecological environmental is as follows: first, setting a visualization strategy, which is to set the specific model hierarchy needed to be displayed, the beginning position of the search point, the number of logical chunks loaded during the initial exploration, and the detailed display requirements for each model hierarchy from far to near search point according to the display quality requirements for each hierarchize. At the beginning of the exploration, flow loading and visualization are carried out based on the above setting and visualization displayed data model. During loading, a loop loading is carried out with the explorer's point as the center, from far to near, and the number of logical chunks are updated according to the movement of the search point to update the scene, the far one is unloaded, the near one is loaded, and visualize it. Wherein, the process of visualizing the logical chunk of the current scene is as follows: separating the loading region into three different loading chunks, with the center region being the highest quality scene chunk (that is the logical chunk), loading the higher-quality scene chunks on the outer ring region chunk immediately following the central region, and simultaneously loading the feature object needed to be displayed in each storey, prioritizing loading the model hierarchy corresponding to larger feature, and loading the outermost storey with lower quality chunk, and selectively loading larger features. In summary, the three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided by the present application comprises: the construction unit 201, the logical chunk unit 202 and the visualization unit 203; wherein, the construction unit 201 is used to construct the three-dimensional virtual ecological environmental model corresponding to an ecological environmental data, and the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to the ecological environmental data and the digital elevation model of an object region; the logical chunk unit 202 is used to perform logical separation on the model hierarchy to obtain the plurality of logical chunks corresponding to each model hierarchy, and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk according to the geographic coordinate of the ecological environmental data and the three-dimensional coordinate of each model hierarchy in the plurality of model hierarchies; wherein, the logical chunk is corresponded to each scene in the scene assembly of the three-dimensional virtual ecological environmental; the visualization unit 203 is used to visualize the scene assembly of the three-dimensional virtual ecological environmental based on the plurality of logical chunks and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk. In this way, during the construction process of model, the scene assembly required for different display accuracies of three-dimensional virtual ecological environmental model of large region is constructed through the construction unit 201 to improve the visualization efficiency of scene assembly of three-dimensional virtual ecological environmental model of large region in game engine; Through the logical chunk unit, the model hierarchy is separated into the plurality of logical chunks to achieve logical segmentation of large region, and each logical chunk or the combination of the plurality of logical chunks is the scene range that the game engine can handle, and the corresponding relationship between logical chunks and each scene in scene assembly is established to index each logical chunk during the visualization process, so as to achieve high realism and efficiency visualization of the threedimensional virtual ecological environmental of large region. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region provided in the present application can visualize and integrate heterogeneous multi-source ecological environmental data that can be obtained, providing high realism and efficient visualization of the ecological environment of large region, so as to support interdisciplinary research, exploration and exchange, and sustainable development decisionmakings related to the ecological environment. The present application provides an open heterogeneous multi-source data and information visualization integration solution, which solves the visualization integration problem of multisource ecological environmental data. By establishing an efficient three-dimensional visualization model of big data ecological environment, the problem of integrated high realism and immersive three-dimensional virtual integration of multi-source heterogeneous and spatio-temporal dynamic data of large region is solved. The present application establishes an efficient visualization model of big data hierarchy and chunk that adapts to Unity3D engine technology, so as to achieve high realism and efficient visualization based on the game engine. The present application also provides an open framework of the visualization integration of multisource heterogeneous data, and converts the corresponding ecological environmental data into a three-dimensional model of FBX format, and visualized it by using Unity3D. The present application is based on the ecological environment large region data efficient visualization model of the Unity3D, which is the foundation of a high realism three-dimensional virtual environment decision-making support system for sustainable development decision-making of large region. By utilizing the visualization technology of the Unity3D engine, the problem of previous systems not being able to balance realism and large region, and to solve the realism problems often need to sacrifice regions, has been solved. At the same time, the visualization problem of realism and large region has been solved. The present application is aimed at sustainable development scientific decision-making of the ecological environment, it introduces immersive virtual reality technology, the personnel involved in decision-making research are placed in the unified spatio-temporal and highly realistic threedimensional virtual environment for hands-on experience and exploration simulation, and truly experiences the environmental phenomena and the potential impact of decision-making, so as to make scientific decisions. The above is only a preferred example of the present application and is not intended to limit it. For those skilled in the art, the present application may have various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of present application application.

Claims

1. A three-dimensional virtual ecological environmental visualization integration and optimization system for large region, characterized in that, the three-dimensional virtual ecological environmental visualization integration and optimization system for large region comprises: a construction unit, a logical chunk unit and a visualization unit;the construction unit is used to construct a three-dimensional virtual ecological environmental model corresponding to an ecological environmental data, and a plurality of model hierarchies corresponding to a scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to the ecological environmental data and a digital elevation model of the large region; wherein, the scene assembly is a scene assembly in a game engine, and the ecological environmental data have a plurality of types, which are a data from different sources and have different data structures;the logical chunk unit is used to perform logical separation on the model hierarchies to obtain a plurality of logical chunks corresponding to each model hierarchy, and a mapping relationship between a three-dimensional coordinate and a geographic coordinate of each logical chunk according to the geographic coordinate of the ecological environmental data and the threedimensional coordinate of each model hierarchy in the plurality of model hierarchies; wherein, the logical chunk is corresponded to each scene in the scene assembly of the three-dimensional virtual ecological environmental;the visualization unit is used to visualize the scene assembly of the three-dimensional virtual ecological environmental based on the plurality of logical chunks and the mapping relationship between the three-dimensional coordinate and the geographic coordinate of each logical chunk;the construction unit comprises a triangle network construction module, a texture mapping module and a data hierarchy module;the triangle network construction module is used to establish a plane triangle network model of the large region, and determine an elevation of each triangle vertex in the plane triangle network model to obtain a three-dimensional triangle network model according to the digital elevation model;the texture mapping module is used to map the ecological environmental data as a texture onto the three-dimensional triangle network model to obtain the three-dimensional virtual ecological environmental model corresponding to the ecological environmental data;the data hierarchy module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain the plurality of model hierarchies corresponding to the scene assembly with different display accuracies of the three-dimensional virtual ecological environmental model according to different display accuracies.

2. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 1, characterized in that, the data hierarchy module comprises a first hierarchy sub-module and a second hierarchy sub-module;the first hierarchy sub-module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain a plurality of model hierarchies with different resolutions corresponding to the ecological environmental data according to the different resolutions, when the three-dimensional virtual ecological environmental model is a three-dimensional terrain model; wherein, the model hierarchy with each resolution is corresponded to each scene assembly;the second hierarchy sub-module is used to hierarchize the three-dimensional virtual ecological environmental model to obtain a plurality of model hierarchies with different feature quantities corresponding to the ecological environmental data according to the feature quantity in the threedimensional virtual ecological environmental model, when the three-dimensional virtual ecological environmental model is a feature model; wherein, each model hierarchy is corresponded to each scene assembly.

3. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 1, characterized in that, the construction unit also comprises a spatio-temporal dynamic data construction module;the spatio-temporal dynamic data construction module is used to sample the ecological environmental data at a preset time interval to obtain a plurality of dynamic images, and map the dynamic image as a texture onto the plane triangle network model to obtain a three-dimensional virtual ecological environmental model of spatio-temporal dynamic according to a temporal order.

4. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 2, characterized in that, the visualizationunit comprises a loading module and a dynamic update module;the loading module is used to obtain N x N adjacent logical chunks, and load the scene assembly based on the N * N adjacent logical chunks; wherein, N is an integer greater than or equal to 1;the dynamic update module is used to update the scene assembly based on a distance between a search point and a target location point in a scene of the three-dimensional virtual ecological environmental.

5. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 4, characterized in that, the dynamic update module comprises a first update sub-module and a second update sub-module;the first update sub-module is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different resolutions according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the three-dimensional terrain model;the second update sub-module is used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with different feature quantities according to the distance between the search point and the target location point, when the three-dimensional virtual ecological environmental model is the feature model.

6. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 5, characterized in that,the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a first resolution, when the distance between the search point and the target location point is greater than a first distance threshold; the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a second resolution, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than a second distance threshold; the first update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a third resolution, when the distance between the search point and the target location point is less than or equal to the second distancethreshold;wherein, the first distance threshold is greater than the second distance threshold, and the first resolution, the second resolution, and the third resolution are increased sequentially;the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with a feature quantity which is greater than a first feature size, when the distance between the search point and the target location point is greater than the first distance threshold; the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the first feature size and greater than a second feature size, when the distance between the search point and the target location point is less than or equal to the first distance threshold and greater than the second distance threshold; the second update sub-module is further used to update the scene assembly by using the logical chunk corresponding to the model hierarchy with the feature quantity which is less than or equal to the second feature size, when the distance between the search point and the target location point is less than or equal to the second distance threshold;wherein, the first feature size is greater than the second feature size.

7. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 1, characterized in that, the visualization unit further comprises an interactive augmentation module;the interactive augmentation module is used to set a visualization display strategy of the model hierarchy, according to the plurality of model hierarchies with different accuracies corresponding to the ecological environmental data.

8. The three-dimensional virtual ecological environmental visualization integration and optimization system for large region according to claim 1, characterized in that, the system further comprises a virtual reality module which is used to perform immersive exploration on the threedimensional virtual ecological environmental based on a virtual reality technology.

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