In the study of 3D route scene construction, the expression of key targets needs to be highlighted. This is because compared with the 3D model, the abstract 3D symbols can reflect the number and spatial distribution characteristics of entities more intuitively. Therefore, this research proposes a symbolic 3D route scene representation method based on the importance of the object. The method takes the object importance evaluation model as the theoretical basis, calculates the spatial importance of the same type of objects according to the spatial characteristics of the geographical objects in the 3D route scene, and constructs the object importance evaluation model by combining semantic factors. The 3D symbols are then designed in a hierarchical manner on the basis of the results of the object importance evaluation and the CityGML standard. Finally, the LOD0-LOD4 symbolic 3D railway scene was constructed on the basis of a railroad data to realise the multi-scale expression of symbolic 3D route scene. Compared with the conventional loading method, the real-time frame rate of the scene was improved by 20 fps and was more stable. The scene loading speed was also improved by 5–10 s. The results show that the method can effectively improve the efficiency of the 3D route scene construction and the prominent expression effect of the key objects in the 3D route scene.

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Research on the Symbolic 3D Route Scene Expression Method Based on the Importance of Objects

Monomerization is one of the important aspects of tilt photography models in practical applications, but the monomerized models lack rich semantic information. In this paper, a multi-scale coupling mechanism of semantic information and monomerization model is designed. Firstly, semantic consistency processing is performed on the crowd source data to obtain rich semantic information. Then, a semantic information classification table is constructed, and two-dimensional semantic information based on CityGML level of detail fusion rules are designed to join the multi-scale functional areas based on CityGML. Finally, multi-scale semantic information is assigned to the monolithic model based on the inclusion relationship between functional areas and buildings. The results of this paper show that the proposed method can integrate the query of the structure and location of 3D monolithic models as well as their rich semantic information, thus providing data support for the application of 2D and 3D systems for data analysis.

Multi-scale coupling mechanism between monolithic models and multisource data

At present, in the related research of 3D line scene, the multi-scale expression method is mostly used to describe the detail degree of geographical features, and there is a lack of a method to describe objects from the perspective of granularity, so it is hard to meet the application requirements of objects in different scenarios. This paper introduces quotient space theory and proposes a representation method of highway geographic entities at different granularity levels. Firstly, the conditions that can be divided into highway geographical entities within the same granularity are determined. Then, the granularity partition model of highway geographic entities is constructed from three aspects: text similarity, literal similarity and semantic distance similarity. Finally, each quotient space is organized by the theory of quotient space particle size synthesis, and the whole geographical entity is divided into multiple granularities, and the experimental verification is carried out. The results show that the method can well meet the multi-level and multi-granularity requirements of geographic entities, and realize the hierarchical optimization of expressway scenes.

Granularity classification method for highways based on granularity synthesis in quotient space

In the research of 3D linear scene construction, the scene construction method based on time or data is difficult to be event-centered, and there is the problem of data redundancy in the construction process. The event driver drives the change in the impact factor of an event during transaction dispatch by calling the corresponding event execution function to finally solve the problem and prevent the transaction from piling up. Based on linear reference model and event-driven, this paper proposes an event-driven model under linear reference system, and then realizes the construction of 3D linear scene driven by event model. Firstly, the basic event model is established by combining the characteristics of linear scene data band distribution. According to the types and logical relations of events in linear scene, the events are classified and the event coding rules under linear reference system are designed to make the event change drive the model attribute change in linear scene. The unified mapping relationship between events and objects is established, and the linear scene construction rules based on event-driven model are designed. Finally, experiments on the construction of dynamic highway scenes were conducted, and the construction of 3D linear scenes based on the event-driven model was realized, and the smoothness of scene rendering was significantly improved compared with the traditional method. The feasibility of efficient construction of 3D linear scenes based on event-driven model is verified. It is of great significance for highway emergency security.

Fulin Han

Papers

Research on the Symbolic 3D Route Scene Expression Method Based on the Importance of Objects

Multi-scale coupling mechanism between monolithic models and multisource data

Granularity classification method for highways based on granularity synthesis in quotient space

Research on event-driven model construction method in linear reference system