RESEARCH ON CONSTRUCTION OF SPATIO-TEMPORAL DATA VISUALIZATION PLATFORM FOR GIS AND BIM FUSION

: The visualization model of GIS and BIM fusion can provide data bearing platform and main technical support for future urban operation centers, digital twin cities, and smart cities. Based on the analysis of the features and advantages of GIS and BIM Fusion, this paper proposes a construction method of the spatio-temporal data visualization platform for GIS and BIM Fusion. It expounds and analyzes the overall architecture design of platform, multi-dimensional and multi-spatial scales visualization, space analysis for GIS and BIM fusion, and platform applications and so on. The urban virtual simulation spatio-temporal data platform project of Teda New District in Tianjin has verified and demonstrated that the effect of application is good. This provides a feasible solution for the construction of spatio-temporal Data Visualization Platform.


INTRODUCTION
The GIS industry has gradually developed from traditional electronic map display, query analysis, and data processing application to big data analysis, mining, and spatio-temporal data visualization, which is developing towards big data, cloud platform, distributed computing, multi-source data integration, etc., and presenting a trend of large scale, micro field and full content. In the era of big data, the GIS industry cannot ignore the temporal and spatial elements of data, so the spatio-temporal big data and management platform come into existence as the situation requires [1][2][3] .
BIM+GIS allows the exchange and interoperability between BIM information in the micro field and GIS information in the macro field, which has become a research hotspot in both academic and industrial circles [4][5][6] . The visualization mode based on GIS+BIM can support multi-level visualization of spatiotemporal big data platform, but the platform needs to support BIM and GIS to store and mine their large data sets [3] .
The GIS platform can be built based on the visualization requirements of spatiotemporal big data, and the urban scene can be built with technologies such as computer graphics, image processing, and human-computer interaction as well as 2D and 3D spatial geographic environments. Combined with business needs, various statistical graphs can be used to display spatial and temporal elements and analysis results. In addition, spatial analysis capability can be used to restore and even augment the global structure and specific details of spatiotemporal data so that the intrinsic value of spatiotemporal big data can be further mined [7][8][9] . Based on TEDA urban spatiotemporal big data platform, this research explored GIS+BIM for the building of spatiotemporal big data visualization platform.

VISUALIZATION PLATFORM
The spatiotemporal big data platform is essentially GIS platform undertaking visual interaction, storing data, and executing other auxiliary functions in the project. Based on GIS+BIM technology, the platform displays visual information of TEDA, such as administrative boundaries of territory and BIM models of major buildings. As the carrier of city operation center and "digital twin city", the platform also provides an approach for urban The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLII-3/W10, 2020 International Conference on Geomatics in the Big Data Era (ICGBD), 15-17 November 2019, Guilin, Guangxi, China This contribution has been peer-reviewed. https://doi.org/10.5194/isprs-archives-XLII-3-W10-555-2020 | © Authors 2020. CC BY 4.0 License. space planning, emergency response, real-time information transmission, and urban problem solving [10][11] .

Fig.1 Overall architecture diagram of GIS development framework
The GIS development framework consists of urban simulation platform, spatiotemporal integration platform, geographic data sharing service platform, and geographic data visualization platform, and each of the four parts bears some functions of the overall GIS framework. Fig. 1 shows the overall architecture of the GIS development framework.

Data layer based on spatiotemporal integration platform
Spatiotemporal data is geospatial data with time tags, including both traditional geospatial data and unstructured data such as text with spatiotemporal tags. Considering diverse sources and formats of spatiotemporal big data, their mining and processing are important tasks for visual representation, because they define unified data management portal, establish spatiotemporal data storage standards, provide automated processing tools, and help complete data handling.
Based on the spatiotemporal big data platform, the exploratory storage is tested according to TEDA data,

Service layer based on geographic data sharing platform
With the geographic data sharing platform as the core, the spatial data service center is built to provide vector map service, tile map service, 3D model service, and business data service; combined with the characteristics of spatial data, it provides spatial

Component layer based on urban simulation platform
The urban simulation platform provides spatial data display components, such as browser-based 2D map and 3D scene. These components developed by JavaScript can be used without plugins and seamlessly integrated with the browser. The core capabilities of these componets are as following: they can provide complete 2D map display framework, satisfy loading and display of multi-source map services, support basic operation of map, and achieve query and basic analysis of spatial data; they can provide urban 3D scene display interface, satisfy loading and display of 3D model and map services, and support data query and positioning, as well as 3D measurement and analysis based on 3D scenes, 2D and 3D linkage; they can display underground 3D pipeline, support management of 3D pipeline model, pipeline data query, and pipeline analysis, and support linkage of 2D map and 3D scene. Based on the 2D and 3D spatial data display components provided by the urban simulation platform, the application system is built to meet the needs of different industries.

Application layer based on geographic data visualization platform
As

Spatial analysis based on GIS+BIM
The spatial analysis on the platform mainly relies on

Governmental application
As a new trend in recent years, the digital office saves