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Detail level conversion method and system for three-dimensional city model

A city model and transformation method technology, applied in the field of geospatial information systems, can solve the problems of inability to process 3D models, not considering internal features, and lack of LoD complete transformation and detailed transformation methods, so as to maintain data storage, small data storage, Quickly extracted effects

Inactive Publication Date: 2018-07-06
HKUST SHENZHEN RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Current general transformation methods (e.g., vertex clustering and edge collapsing), due to the limitations of their data sources, and do not consider 3D building models with internal features (e.g., rooms or furniture), are therefore not applicable where internal features are built. Modular CityGML model, cannot handle complex 3D models with a large number of surfaces
Therefore, there is currently no detailed conversion method for full conversion between LoDs in CityGML

Method used

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  • Detail level conversion method and system for three-dimensional city model
  • Detail level conversion method and system for three-dimensional city model
  • Detail level conversion method and system for three-dimensional city model

Examples

Experimental program
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Embodiment 1

[0046] This embodiment provides a method for LOD conversion for a 3D city model. see figure 1 , the level of detail conversion method for a 3D city model includes the following steps:

[0047] Step S110: Analyzing the input CityGML file, extracting geometric data and semantic information contained therein, generating building components, and outputting a LoD4 hierarchical model.

[0048] CityGML uses Boundary Representation (BRep) to model the geometry of city objects, so each building component is bounded by some planes to show its 3D shape. Therefore, in this embodiment, the building components are a set of planes with corresponding semantic information.

[0049] Specifically, in this embodiment, the open-source citygml4j Java library is used to convert between CityGML files and Java classes during the data input process, and convert the input CityGML files into Java classes.

[0050] Further, for a given input 3D city model, all buildings are located first. Next, with t...

Embodiment 2

[0066] This embodiment provides a method for LOD conversion for a 3D city model. see figure 2 , the level of detail conversion method for a 3D city model includes the following steps:

[0067] Step S210: Analyzing the input CityGML file, extracting geometric data and semantic information contained therein, generating building components, and outputting a LoD4 hierarchical model.

[0068] As shown in Table 1, the architectural components in the LoD4 hierarchical model include rooms, openings, interior architectural decoration, furniture, inner ceiling surface, outer ceiling surface, inner wall surface, inner floor surface, outer floor surface, roof surface, building Trims, walls, floors, closures and roof overhangs.

[0069] Step S220: remove the interior architectural decoration, the furniture, the inner ceiling surface, and the inner wall surface in the LoD4 hierarchical model, simplify the opening in the LoD4 hierarchical model, and use the shell extraction algorithm The...

Embodiment 3

[0086] image 3 It is a schematic diagram of a LOD conversion system for a 3D city model provided by an embodiment of the present invention. Such as image 3 As shown, the LOD conversion system for a 3D city model includes a data preprocessing module 310 and a conversion module 320 .

[0087] The data preprocessing module 310 is used to analyze and process the input CityGML file, extract the geometric data and semantic information contained therein, and generate building components. The building components are a group of planes with corresponding semantic information, including:

[0088] A positioning unit 312, configured to locate the building to be analyzed;

[0089] The extraction unit 314 is configured to extract building components according to the geometric and semantic features of the LoD4 level.

[0090] The conversion module 320 includes a first conversion unit 322, a second conversion unit 324, a third conversion unit 326 and a fourth conversion unit 328, wherein:...

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Abstract

The invention provides a detail level conversion method for a three-dimensional city model. The method comprises the steps that an input CityGML file is parsed, and geometric data and semantic information contained therein are extracted to generate a building component; a LoD4 hierarchical model is output; indoor building components in the LoD4 hierarchical model are removed; a shell extraction algorithm is used to extract a building shell; the geometric features of the LoD4 hierarchical model are converted into LoD3 hierarchical geometric features, and a LoD3 hierarchical model is output; opening features and external building decorative components in the LoD3 hierarchical model are removed; the geometric features of the LoD3 hierarchical model are converted into the geometric features ofLoD2 hierarchy, and a LoD2 hierarchical model is output; a roof structure in the LoD2 hierarchical model is removed; the geometric features of the LoD2 hierarchical model are converted into the geometric features of LoD1 hierarchy; and a LoD1 hierarchical model is output. According to the invention, building components of different detail levels are clarified; a conversion mechanism between different detail levels is established; and a 3D building model with internal features can be quickly converted between different detail levels.

Description

technical field [0001] The present invention relates to the technical field of geospatial information systems, in particular to a method and system for converting between different detail levels of a three-dimensional city model. Background technique [0002] 3D geographic information system (GIS) models are increasingly used for planning and analysis at the city level. It is often necessary to define 3D GIS city models with different levels of detail (LoD) in order to browse and handle large models more efficiently. When traversing a 3D city model in a multi-LoD GUI, the object's distance changes, so the LoD representation of the object needs to be modified accordingly. Therefore, there is a need for automatic and fast conversion between LoDs of 3D GIS city models. [0003] Of all the common 3D GIS standards currently available, City Geographic Markup Language (CityGML) has the most complex definition of LoD. CityGML is a general modeling language for 3D city objects lau...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T17/05G06F17/30
CPCG06T17/05G06F16/29
Inventor 邓逸川郑展鹏
Owner HKUST SHENZHEN RES INST
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