A method and device for displaying localized geographic information in a large-scale scenario

Abstract

This invention provides a method and apparatus for displaying localized geographic information in large-scale scenes, enabling real-time display and interaction of large-scale geographic scenes at the global and city levels. By managing the local coordinate system of cameras, terrain tiles, and various 3D geographic objects within the geographic scene, it effectively improves the display accuracy and stability of large-scale 3D GIS scenes. This invention constructs a local coordinate system to dynamically convert global geographic data to a local space for high-precision rendering, avoiding model jitter and misalignment problems caused by insufficient floating-point precision in traditional world coordinate systems. Simultaneously, this method combines the view frustum clipping and layer detail technology of the visual engine to achieve efficient scheduling and rendering of terrain tiles and 3D objects, significantly improving frame rate stability and interactive smoothness in large-scale scenes.

Description

Technical Field

[0001] This invention belongs to the field of 3D geographic information visualization and scene rendering technology, specifically relating to a method and device for displaying localized geographic information in large-scale scenes. Background Technology

[0002] With the development of Geographic Information System (GIS) technology, 3D GIS visualization engines are widely used in fields such as digital earth, 3D maps, smart cities, and aerospace simulation. These systems typically require continuous roaming, real-time rendering, and interactive display of large-scale geographic scenes at the Earth or city level.

[0003] In existing 3D GIS visualization engines, geographic objects such as terrain, image tiles, roads, airports, and building models are typically organized and rendered based on a unified world coordinate system, with coordinate values ​​often reaching millions or even tens of millions. When the camera moves across a large geographic scene, these large coordinate values ​​need to participate in a large number of floating-point operations during the continuous transformation of the model matrix, view matrix, and projection matrix.

[0004] Because existing graphics rendering systems generally use single-precision floating-point numbers for vertex calculations, the effective precision of floating-point numbers will decrease significantly when the coordinate values ​​are too large, leading to the following problems: 1. Unevenness, distortion, or wavy distortion appear on large-area planes such as terrain and airport runways; 2. Unstable phenomena such as shaking and flickering occur during long-distance camera roaming; 3. The vertices of triangles that were originally located on the same plane lose their coplanar relationship in clipping space, affecting visual consistency; 4. The above problems are further amplified under different viewing angles and scaling scales, seriously affecting the display quality of the 3D GIS visual engine.

[0005] To address the aforementioned issues, existing technologies typically employ the following solutions: One approach mitigates precision loss by increasing floating-point calculation accuracy or introducing double-precision arithmetic, but this approach consumes significant hardware resources and is difficult to implement comprehensively in real-time rendering scenarios; another approach reduces the numerical range by locally modifying the model or camera matrix, but often lacks a unified management mechanism, leading to issues such as repeated object offsets, high logical coupling, and maintenance difficulties in complex 3D GIS systems.

[0006] Especially in actual engineering, different types of geographic objects (such as terrain tiles, batch models, dynamic wireframes, etc.) often adopt different data organization and update methods. If there is a lack of a unified and clear localization display strategy, the coordinate update logic is easily scattered in various modules, which makes the system more vulnerable to expansion and reuse.

[0007] Therefore, how to provide a geographical information display method for 3D GIS visual engines that is structurally clear, highly decoupled, and suitable for large-scale scenarios without significantly increasing rendering costs has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] This invention provides a method and apparatus for displaying localized geographic information in large-scale scenes, aiming to solve the problems of insufficient display accuracy, scene instability, and complex engineering implementation caused by excessively large world coordinate values ​​in existing 3D GIS visual engines during the display of large-scale geographic scenes.

[0009] The first aspect of this invention provides a method for displaying localized geographic information in large-scale scenarios, comprising the following steps: During GIS engine initialization, the initial world coordinate position of the camera is used as the origin of the local coordinate system to construct a local coordinate system. The coordinate axis directions of the local coordinate system are consistent with those of the world coordinate system. Geographic objects in the 3D GIS scene are uniformly converted to the local coordinate system for display according to their types. The types include: global offset objects and vertex self-localization objects. During the operation of the GIS engine, the position change of the camera in the local coordinate system is detected in real time. When the distance between the camera and the origin of the local coordinate system exceeds a preset threshold, the world coordinate position of the current camera is set as the new origin of the local coordinate system. Based on the new origin of the local coordinate system, the position of the geographic objects is adjusted according to their type.

[0010] Optionally, the location of geographic objects can be adjusted by type, including: For objects with an overall offset, the position of the root node of this type of object is adjusted according to the offset from the origin, and its child nodes are automatically updated along with the parent node. Global offset objects include, but are not limited to: 3D models, camera nodes, and interface or annotation objects in world space.

[0011] Optionally, the location of geographic objects can be adjusted by type, including: For vertex self-localization objects, the new local coordinate system is adapted by recalculating or updating their vertex data, while the position of their parent node remains zero. Vertex self-localization objects are those whose vertex coordinates have been transformed from world coordinates to local coordinates during their geometry data generation or update phase, including but not limited to: terrain tiles, batched geometry, and dynamic lines.

[0012] Optionally, before adjusting the location of geographic objects by type, the method further includes: Determine if a geographic object has been registered as an object that does not require overall offset; If yes, then the geographic object is determined to be a vertex self-localized object; otherwise, the geographic object is determined to be a global offset object.

[0013] Optionally, after setting the current world coordinate position of the camera as the origin of the new local coordinate system, the method further includes: Trigger all registered callback functions; Correspondingly, the location of geographic objects is adjusted according to their type, including: The vertex self-localization object adjusts its position in the callback function.

[0014] A second aspect of the present invention provides a localized geographic information display device for large-scale scenarios, comprising: The initialization module is used to construct a local coordinate system during GIS engine initialization, using the camera's initial world coordinate position as the origin of the local coordinate system. The coordinate axes of the local coordinate system are consistent with those of the world coordinate system. Geographic objects in the 3D GIS scene are uniformly converted to the local coordinate system for display according to their types. The types include: global offset objects and vertex self-localization objects. The update module is used to detect the position changes of the camera in the local coordinate system in real time during the operation of the GIS engine. When the distance between the camera and the origin of the local coordinate system exceeds a preset threshold, the current world coordinate position of the camera is set as the new origin of the local coordinate system, and the position of the geographic objects is adjusted according to the type based on the new origin of the local coordinate system.

[0015] Optionally, the update module is specifically used for: For objects with an overall offset, the position of the root node of this type of object is adjusted according to the offset from the origin, and its child nodes are automatically updated along with the parent node. Global offset objects include, but are not limited to: 3D models, camera nodes, and interface or annotation objects in world space.

[0016] Optionally, the update module is specifically used for: For vertex self-localization objects, the new local coordinate system is adapted by recalculating or updating their vertex data, while the position of their parent node remains zero. Vertex self-localization objects are those whose vertex coordinates have been transformed from world coordinates to local coordinates during their geometry data generation or update phase, including but not limited to: terrain tiles, batched geometry, and dynamic lines.

[0017] A third aspect of the present invention provides a computer-readable storage medium, comprising: a memory and a processor; The memory is configured to store executable instructions; The processor is configured to implement the method as described in any one of the first aspects when executing the executable instructions stored in the memory.

[0018] A fourth aspect of the present invention provides a computer program product comprising instructions that, when executed by a computer, implement the method as described in any one of the first aspects.

[0019] This invention provides a method and apparatus for displaying localized geographic information in large-scale scenarios, which has at least the following beneficial effects: 1. Significantly improves the display accuracy of large-scale 3D GIS scenes. By introducing a local coordinate system management mechanism, the coordinate values ​​of geographic objects are restricted to a smaller range, effectively reducing the loss of floating-point precision during the calculation of model matrix, view matrix, and projection matrix, and ensuring the stability of vertex calculation.

[0020] 2. Effectively eliminates distortion phenomena in large-scale planar geometry. In the display of large-area planar objects such as airport runways and terrain tiles, it can maintain the coplanar relationship of triangle vertices in the clipping space, avoiding display problems such as texture distortion and unevenness caused by insufficient precision.

[0021] 3. Suitable for displaying large-scale geographical scenes during continuous roaming. By using a dynamic local coordinate system update mechanism triggered by camera motion, the camera is always kept in a high-precision coordinate space, making it suitable for long-distance continuous roaming in Earth-scale or city-scale scenarios.

[0022] 4. Reduce system engineering coupling and improve maintainability By distinguishing between global offset objects and vertex self-localization objects, and combining this with a callback mechanism for decoupling management, the coordinate update logic is avoided from being scattered across multiple business modules, thus reducing system complexity.

[0023] 5. Possesses good scalability and reusability. When adding new geographic objects or functional modules, you only need to select the appropriate localization strategy based on the characteristics of the object and register the corresponding callback. There is no need to modify the core local coordinate system management logic, which facilitates system expansion and reuse.

[0024] 6. No need to rely on high-precision hardware or complex rendering pipeline modifications. This invention can be implemented in the existing single-precision floating-point rendering system without relying on double-precision calculation or special hardware support, and has good engineering practical value. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A flowchart illustrating the localized geographic information display method for large-scale scenarios provided by the present invention; Figure 2 A schematic diagram of the core components of the local coordinate system provided by this invention; Figure 3 A schematic flowchart of the localization update method for a camera provided by the present invention; Figure 4 This is a flowchart illustrating the local coordinate system origin update method provided by the present invention. Figure 5 This is a flowchart illustrating the classification and differentiation update method for geographic objects provided by the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0029] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0031] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0033] Specifically, such as Figure 1-5 As shown, this invention proposes a method for displaying localized geographic information in large-scale scenes. The purpose of this invention is to dynamically map cameras, terrain tiles, and various 3D geographic objects in a geographic scene to a high-precision local coordinate space by introducing a unified local coordinate system management mechanism into a 3D GIS visual engine. This ensures display accuracy while reducing system coupling and improving the maintainability and scalability of the overall project.

[0034] The localized geographic information display method for large-scale scenes provided by this invention is applied in 3D GIS visual engines, such as... Figure 1 As shown, it includes the following steps: 1. During the system initialization phase, based on the initial geographical location, a local coordinate system is constructed with the initial position of the camera as the origin of the local coordinate system, and the coordinate axis directions of the local coordinate system are consistent with those of the world coordinate system; 2. During the geographic scene loading process, the camera, model, and terrain tiles are uniformly converted to the local coordinate system for display; 3. During system operation, the positional changes of the camera in the local coordinate system are detected in real time; 4. When the distance between the camera and the current local coordinate system origin exceeds a preset threshold, the local coordinate system origin is updated. 5. During the local coordinate system origin update process, coordinate update processing is performed on each type of geographic object according to the localization method of different types of geographic objects; 6. Notify relevant functional modules to perform recalculation operations related to local coordinate system updates through a callback mechanism.

[0035] This invention employs a local coordinate system design that updates only the origin without changing the direction of the coordinate axes. This approach effectively reduces the range of coordinate values ​​involved in rendering calculations without introducing additional rotation errors, thereby improving the accuracy of floating-point calculations.

[0036] The local coordinate system is dynamically adjusted with the camera position as the core, so that the camera is always in the center of the high-precision coordinate space, which is suitable for large-scale continuous roaming 3D GIS scenes.

[0037] In this invention, the update of the local coordinate system is triggered by the camera's motion state. When the camera's displacement in the local coordinate system exceeds a preset distance threshold, the system sets the current world coordinate position of the camera as the origin of the new local coordinate system.

[0038] This method ensures visual continuity while avoiding frequent updates to the local coordinate system, thus balancing display accuracy and system performance.

[0039] To reduce engineering coupling, this invention classifies objects in a 3D GIS scene into at least the following two categories based on the coordinate management method of geographic objects: 1. Global offset objects: These objects adapt to a new local coordinate system by updating their overall position. They are suitable for ordinary 3D models, camera nodes, and interface objects in world space. 2. Vertex self-localization objects: These objects have completed local coordinate transformation during the generation or update of their vertex data. When updating the origin of the local coordinate system, there is no need to perform a global offset again. They are suitable for objects such as terrain tiles and batch geometry.

[0040] The above classification method can effectively avoid problems such as duplicate object offset or coordinate superposition errors.

[0041] To avoid strong coupling calls between various business modules during the local coordinate system update process, this invention introduces a localized update scheme based on a callback mechanism.

[0042] When the origin of the local coordinate system is updated, the local coordinate system management module is only responsible for notifying each registered callback function. Each business module decides whether and how to respond to the update of the local coordinate system according to its own needs, thereby achieving decoupling and independent expansion between modules.

[0043] Through the above technical solution, the present invention can realize a localized geographic information display method suitable for large-scale geographic scenes in a 3D GIS visual engine, so that geographic objects maintain a stable and accurate display effect under different viewing distances and continuous roaming conditions, and significantly reduce the system implementation complexity.

[0044] In a specific embodiment, the localized geographic information display method for large-scale scenarios provided by the present invention includes the following: I. Initialization Method of Local Coordinate System When the 3D GIS visualization engine starts, a local coordinate system is constructed based on the initial geographic location. This local coordinate system uses the camera's initial world coordinate position as its origin, and its coordinate axes are aligned with the global world coordinate system; only the origin position is managed. This initialization process includes: 1. Obtain the initial world coordinates of the camera; 2. Set this location as the origin of the local coordinate system; 3. All subsequent geographic objects loaded in the scene are uniformly considered to be under this local coordinate system.

[0045] By employing the above method, the use of large-value world coordinates in rendering calculations is avoided during the system startup phase. The core components of a local coordinate system are as follows: Figure 2 As shown.

[0046] II. Local Update Methods for Cameras During system operation, when updating the camera state in each frame, such as Figure 3 As shown, the following processing method is adopted: 1. Obtain the camera's world coordinate position and orientation information from external data sources or system status; 2. Convert the camera's world coordinate position to its local coordinate position using the following method: Camera local coordinates = camera world coordinates Current local coordinate system origin; 3. Set the transformed local coordinate position to the camera node, while keeping the camera orientation unchanged.

[0047] This method ensures that the camera is always within a high-precision local coordinate space.

[0048] III. Local Coordinate System Update Triggering Method Based on Camera Displacement To avoid the impact of frequent updates to the local coordinate system on system performance, this invention adopts a triggering mechanism based on camera displacement: 1. Calculate the length of the camera's position vector in the local coordinate system in real time; 2. Compare this length with a preset distance threshold; 3. When the length exceeds the threshold, a local coordinate system origin update operation is triggered.

[0049] When an update is triggered, the current world coordinate position of the camera is set as the origin of the new local coordinate system.

[0050] IV. Local Coordinate System Origin Update Method When the origin of the local coordinate system needs to be updated, such as Figure 4 As shown, perform the following steps: 1. Record the position of the local coordinate system origin before the update; 2. Set the new local coordinate system origin position; 3. Calculate the offset between the origins of the old and new local coordinate systems; 4. Based on the offset, adjust the position of the geographic objects in the scene that need to be offset as a whole.

[0051] By updating only the origin without changing the direction of the coordinate axes, we avoid introducing additional rotation errors.

[0052] V. Classification and Differentiated Update Methods for Geographic Objects To avoid duplicate offsets of different objects or confusion in processing logic, this invention classifies and manages geographic objects in a 3D GIS scene, such as... Figure 5 As shown: (a) Global offset type objects Global offset objects refer to objects whose geometry does not automatically handle local coordinates, but rather adapts to changes in the local coordinate system by updating the object's overall position. These include, but are not limited to: 1. Standard 3D model; 2. Camera node; 3. Interfaces or labeled objects in world space.

[0053] When the origin of the local coordinate system is updated, only the position of the root node of this type of object is adjusted according to the origin offset, and its child nodes are automatically updated along with the parent node.

[0054] (ii) Vertex self-localization objects Vertex self-localization objects refer to objects whose vertex coordinates have been transformed from world coordinates to local coordinates during their geometry data generation or update phase, including but not limited to: 1. Terrain tiles; 2. Batch batching geometry; 3. Dynamic wireframes and other geometric data.

[0055] For this type of object, when the origin of the local coordinate system is updated, its overall position is no longer offset. Instead, its vertex data is recalculated or updated to adapt to the new local coordinate system, while its parent node position remains zero.

[0056] VI. Registration and Management Methods for Objects Without Global Offset To achieve the above-mentioned differentiated processing, the present invention provides a registration mechanism that does not require global offset objects, including: 1. Provide an object registration interface for declaring an object as a vertex self-localization object; 2. During the local coordinate system update process, first determine whether the object has been registered as an object that does not require global offset; 3. Skip the overall offset processing logic for registered objects.

[0057] This mechanism avoids incorrect, repeated offsets of objects during local coordinate system updates.

[0058] VII. Localized Update Notification Method Based on Callback Mechanism To reduce the coupling between the local coordinate system management module and the business module, this invention introduces a callback-based update notification mechanism: 1. Provide a callback function registration interface, allowing each business module to register its localized update callbacks during the initialization phase; 2. When the origin of the local coordinate system is updated, all registered callback functions are triggered sequentially; 3. Each business module performs necessary recalculation or refresh operations in its callback function based on its own data characteristics.

[0059] This approach allows the local coordinate system management module to be responsible only for coordinate system maintenance, without directly participating in specific business logic.

[0060] Through the above specific implementation methods, when performing continuous camera roaming in a large-scale 3D GIS scene, it is possible to keep all kinds of geographic objects in the scene within a high-precision coordinate space, effectively avoiding problems such as planar distortion, jitter, and display abnormalities caused by insufficient floating-point precision.

[0061] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for displaying localized geographic information in large-scale scenarios, characterized in that, Includes the following steps: During GIS engine initialization, the initial world coordinate position of the camera is used as the origin of the local coordinate system to construct a local coordinate system. The coordinate axis directions of the local coordinate system are consistent with those of the world coordinate system. Geographic objects in the 3D GIS scene are uniformly converted to the local coordinate system for display according to their types. The types include: global offset objects and vertex self-localization objects. During the operation of the GIS engine, the position change of the camera in the local coordinate system is detected in real time. When the distance between the camera and the origin of the local coordinate system exceeds a preset threshold, the world coordinate position of the current camera is set as the new origin of the local coordinate system. Based on the new origin of the local coordinate system, the position of the geographic objects is adjusted according to their type.

2. The method for displaying localized geographic information in large-scale scenarios according to claim 1, characterized in that, Adjusting the location of geographic objects by type includes: For objects with an overall offset, the position of the root node of this type of object is adjusted according to the offset from the origin, and its child nodes are automatically updated along with the parent node. Global offset objects include, but are not limited to: 3D models, camera nodes, and interface or annotation objects in world space.

3. The method for displaying localized geographic information in large-scale scenarios according to claim 1, characterized in that, Adjusting the location of geographic objects by type includes: For vertex self-localization objects, the new local coordinate system is adapted by recalculating or updating their vertex data, while the position of their parent node remains zero. Vertex self-localization objects are those whose vertex coordinates have been transformed from world coordinates to local coordinates during their geometry data generation or update phase, including but not limited to: terrain tiles, batched geometry, and dynamic lines.

4. The method for displaying localized geographic information in large-scale scenarios according to claim 1, characterized in that, Before adjusting the location of geographic objects by type, the method further includes: Determine if a geographic object has been registered as an object that does not require overall offset; If yes, then the geographic object is determined to be a vertex self-localized object; otherwise, the geographic object is determined to be a global offset object.

5. The method for displaying localized geographic information in large-scale scenarios according to claim 3, characterized in that, After setting the current world coordinate position of the camera as the origin of the new local coordinate system, the method further includes: Trigger all registered callback functions; Correspondingly, the location of geographic objects is adjusted according to their type, including: The vertex self-localization object adjusts its position in the callback function.

6. A localized geographic information display device for large-scale scenarios, characterized in that, include: The initialization module is used to construct a local coordinate system during GIS engine initialization, using the camera's initial world coordinate position as the origin of the local coordinate system. The coordinate axes of the local coordinate system are consistent with those of the world coordinate system. Geographic objects in the 3D GIS scene are uniformly converted to the local coordinate system for display according to their types. The types include: global offset objects and vertex self-localization objects. The update module is used to detect the position changes of the camera in the local coordinate system in real time during the operation of the GIS engine. When the distance between the camera and the origin of the local coordinate system exceeds a preset threshold, the current world coordinate position of the camera is set as the new origin of the local coordinate system, and the position of the geographic objects is adjusted according to the type based on the new origin of the local coordinate system.

7. The localized geographic information display device for large-scale scenarios according to claim 6, characterized in that, The update module is specifically used for: For objects with an overall offset, the position of the root node of this type of object is adjusted according to the offset from the origin, and its child nodes are automatically updated along with the parent node. Global offset objects include, but are not limited to: 3D models, camera nodes, and interface or annotation objects in world space.

8. The localized geographic information display device for large-scale scenarios according to claim 6, characterized in that, The update module is specifically used for: For vertex self-localization objects, the new local coordinate system is adapted by recalculating or updating their vertex data, while the position of their parent node remains zero. Vertex self-localization objects are those whose vertex coordinates have been transformed from world coordinates to local coordinates during their geometry data generation or update phase, including but not limited to: terrain tiles, batched geometry, and dynamic lines.

9. A computer-readable storage medium, characterized in that, include: Memory and processor; The memory is configured to store executable instructions; The processor is configured to implement the method as described in any one of claims 1 to 5 when executing the executable instructions stored in the memory.

10. A computer program product, characterized in that, The computer program product includes instructions that, when executed by a computer, implement the method as described in any one of claims 1-5.

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