The concept of digital earth was originally proposed by US Vice President Al Gore, and its core content is the digitization of global information. Digital Earth mainly refers to the application of geographic information systems, remote sensing, global positioning systems and other technologies to digitally acquire, process and apply spatial data on the natural and human factors of the Earth, and on this basis solve global problems. Nowadays, the information technology revolution has swept the world, and the technical means and concepts of human beings processing and analyzing geospatial data have undergone earth-shaking changes. In this case, one can integrate a large number of multi-resolution, three-dimensional, and dynamic data about the Earth into geographic coordinates to form a digital earth. With this digital earth, people can learn about any and every aspect of the earth in geographic coordinates, no matter where they go. The digital earth is the digital emphasis and understanding of the unity of the real earth and its related phenomena. The core idea has two points: one is to use the digital means to uniformly deal with the earth and the problem; the other is to make maximum use of information resources. Digital Earth consists of the following systems: data acquisition and update systems, data processing and storage systems, information extraction and analysis systems, data and information dissemination systems, database systems, network systems, and specialized software systems. Digital Earth can contain more than 80% of human information resources, and is the core of future information resources. Digital Earth has specific goals in different historical periods. At present, the establishment of multi-scale, multi-application digital cities can provide services for sustainable development more widely and deeply. This is an important step and microcosm of the realization of digital earth, and it is also one of the hot issues in GIS research.
The study of digital cities is not only a simple study of various technologies, but also a data sharing and system interoperability technology as well as management and political fund projects: many natural technical factors and humanities of the National Natural Science Foundation of China (50378093) Integration of factors. The digital city embodies a new concept of people-oriented. In the digital city, everyone can obtain the digital information of the relevant city with the corresponding authority at any time, and use it to assist in daily affairs, scientific research, effective management of enterprises and Various decisions show that digital cities will largely change the way people live and work. In developed countries, the computer systems of urban management departments have gone through three stages of development, namely, the early management information system MIS, the medium-term urban geographic information system (UGIS), and the rapidly developing digital city system. The digital city is a long-term goal for the sustainable development of urban digital information construction system is currently in the exploration stage. In China, GIS technology has become a powerful support tool for urban planning, construction and management. However, there are many professional systems in the urban sector. These systems are not open to each other, resources are difficult to share, and the ability of GIS to comprehensively integrate spatial data and multimedia attribute data at different levels according to uniform geographic coordinates cannot be fully utilized. Many urban issues involving multiple departments that require industry-to-industry collaboration.
In the face of the city's massive data comprehensive management, extensive public inquiry needs, intelligence and networking, and other practical issues, new technical approaches are urgently needed. It is obvious that digital city research is imperative.
Digital lighting is an important part of digital cities. Lighting is not only the sun in the city at night, but also an indispensable element in expressing the city. Digital lighting is based on digital design, digital lighting design and visual night lighting. The computer hard disk, floppy disk, etc. are used as storage media. The content is represented by numbers, which need to be used by special computer software. Digitally digitized information for display, reading, retrieval, and analysis. Digital lighting makes it easy to combine, stitch, record new information, and derive new data into existing designs. The output can be plotted in any scale and range.
It is easy to modify and can greatly shorten the drawing time; the visualization technology using digital illumination can visually represent the scene shape and lighting effect.
2 Digital Lighting Content Digital lighting is based on computer technology, multimedia technology and large-scale storage technology. It uses remote sensing, telemetry, computer network, multimedia and simulation-virtual technology to carry out all the lighting facilities, functional mechanisms and lighting effects of the city. Multi-resolution, multi-scale, multi-time-space and multi-dimensional three-dimensional description and dynamic monitoring and management, technical system for auxiliary decision-making services, that is to say, digital lighting has a very good urban lighting information network, and this information network is digital, Multimedia, intelligent visualization, three-dimensional dynamic urban lighting system. And use this as a tool to support and improve the quality of lighting design and improve lighting effects. Digital lighting can be understood first as information networking.
Digital lighting refers to the digitization of urban lighting facilities, the establishment of a database, and the use of computer high-speed communication networks to achieve network management and regulation, and a highly automated, intelligent technology system. It has powerful functions such as digitization, networking, virtual policy, optimization decision support and visual performance of urban lighting system. It can directly provide convenient lighting services for the government and the public, and can transform the traditional home-controlled lighting mode. It is a highly automated and intelligent urban unified regulation mode to ensure the coordinated development of urban lighting and the environment.
2.1 The technical basis of digital lighting Digital lighting is based on the research of 3S, absorbing the content of theoretical research such as computer graphics and virtual reality, and involves the urban government and people and various urban environments and other urban elements. The basic research of digital lighting focuses on the interconnection and interaction of various elements of urban lighting, and then establishes the physical model, mathematical model, information model and computer model of urban lighting. It involves urban development theory, 3S technology and theory, and related standards.
Basic research on digital lighting () includes: digital acquisition and editing. The system converts existing data, data, etc. into computer-compatible digital forms and corresponding standard data formats.
Information storage and management. Utilize the massive storage function of the system to carry out multi-dimensional structure of various information required for digital lighting, such as urban lighting planning, municipal power grid, road traffic, lighting, brightness distribution and policies and regulations, according to different historical, current and future tense. Storage and efficient management in the system.
Dynamic query and analysis of information. The system can quickly perform dynamic query and statistical analysis of single or multiple elements on stored information. At the same time, the system relies on spatial data and non-spatial data to carry out construction project investment analysis, illumination source and fixture analysis and project tracking supervision, and then realize computerized planning management, lighting design management, file management, and complete urban power grid and road network. Network analysis, lighting, brightness suitability evaluation, urban lighting environmental quality assessment and rational use of resources.
Online publishing and various forms of information output. Utilize the latest computer network technology to release public information resources to the public through the Internet. At the same time, using printers, plotters, hard copy machines and other equipment, quickly output a variety of query retrieval, statistics and results.
2.2 Digital Lighting Implementation Technology Research The technical support system of digital lighting consists of data acquisition, storage, transmission processing and reality (). Some of the most important and direct technologies involved include: remote sensing Earth observation technology, electrical lighting technology, network technology, computer graphics technology, and virtual display technology. Specifically, it includes the acquisition and update of lighting data, distributed network services, data interoperability technology, multi-scale multi-temporal multi-origin data integration technology and interactive 3D visualization technology.
2.3 Digital Lighting Engineering Research Digital lighting engineering is a combination of basic research and technical support systems in digital cities. In a specific city area, software development through data collection, storage, transmission processing and display technologies. Integrate with hardware to create a runnable, distributed and open urban lighting network information system. That is to use the relevant computer software and hardware, through the acquisition of urban data and computer input, establish urban lighting data model and digital expression and store and process the database of urban lighting data, through the sharing, analysis and application of urban lighting data. Data digitization, visualization and network 3 digital lighting implementation technology The current hot issues in digital city research are mainly the management of massive data, data sharing and interoperability, and the research of 3D visualization system. These technologies are also realized by digital lighting. The essential.
Digital lighting is a real digital, networked and virtual representation of lighting. It is a complex and huge networked spatial information system. It uses the "digital earth" theory, based on 3S (GIS, GPS, GPS, RS system). Key technologies such as network data infrastructure and urban lighting data infrastructure to build spatial data centers and application service platforms, integrating networking, geometric data, knowledge, functions, services, applications and models through information portals and application portals It serves urban lighting planning, construction and management, serves the government, enterprises and the public, and serves the sustainable development of population, resources and environment, and economy and society.
3.1 Geometric data storage and management Remote sensing, global positioning system and other various information sources are continuously integrated, and the history and development of objects are used to organize and store data for users to analyze data. Data warehouse is a collection of subject-oriented, integrated, stable and different time data that supports management decision-making process. It is born with the development of GIS technology and parallel database. It is not a simple stacking of multiple databases. It is the process of extracting, purifying and transforming source data. The spatial data warehouse system in digital lighting (), like the general large-scale GIS spatial data warehouse system, is composed of GIS source data, data processing, spatial data warehouse, warehouse. Management and data analysis tools are mostly composed of 5. As the information source manager and logic provider of digital lighting, spatial data warehouse can effectively organize and manage the massive spatial data and attribute data in digital lighting, and comprehensively apply the ideas, methods and techniques of multidisciplinary fields. Data is standardized, refined, classified, aggregated and other spatial data mining operations to obtain a seamlessly integrated spatial data source to meet the needs of digital lighting applications and services for information sources. In this multi-level complex system, for unified time or behavior, different levels of subsystems for information 3.2 interoperable urban lighting is a huge, multi-component, multi-level, multi-functional open complex system, urban lighting This feature of the system is naturally projected into its abstract urban lighting information system. The computer: / digital lighting "also has an open system structure and an open platform hierarchy. The smooth operation of the urban lighting system depends on In the exchange of information between the various subsystems, any typical behavior in the system involves multi-level and multi-sector information exchange. Therefore, the interoperability technology of multiple data is solved, and the various departments can be guaranteed. Interoperability refers to the ability of two or more systems to exchange information and exchange information with each other, that is, the ability of one system to receive and process information sent by another system, showing whether the system is easy to interface with another software system. Two or more entities in a heterogeneous environment, despite the language they implement, the ring of execution Environments are based on different models, but can communicate and collaborate with each other to accomplish a specific task. It can be seen that interoperability emphasizes whether software systems with different data structures and data formats can be integrated and work together. Interoperability means In the case of heterogeneous databases and distributed computing, users can transparently obtain the required information on the basis of mutual understanding. According to the specifications promulgated by OGC, the software that provides the data source can be called the data server, and the software that uses the data. A data client, a project that uses data from a data client, is a project that issues data requests and services provided by the data server. The ultimate goal is to enable data clients to read spatial data from any data server. The interoperability of digital lighting is The bottom-up combination between the existing urban lighting information system and the application system refers not only to the information sharing exchange between different systems, but also to the functional interoperability and coordination between different systems without data exchange. Interoperability in digital lighting can not only answer ubiquitous urban lighting information Interoperability problems, propose solutions to problems such as sharing, exchange, and interoperability, solve the negative impacts of urban lighting information that cannot be interoperable in various fields; and effectively use existing urban lighting information system resources for each Lighting users provide urban lighting information, laying the foundation for digital lighting.
3.3 Visualization of urban lighting The interactive 3D visualization technology of digital lighting is dedicated to organizing various information of different regions and different departments through the Internet base, and obtaining urban lighting geographic coordinates by means of two-dimensional and three-dimensional complementary urban lighting information models. Describe all the information of each point in the three-dimensional space, and provide effective, convenient and intuitive means of inspection, display and analysis, and finally realize the visualization framework of three-dimensional spatial position and attribute information. Visualization technology enables people to manipulate and analyze information about specific shapes in a three-dimensional virtual world. It includes color processing, texture mapping, animation, fogging effects, and transparent processing. The 3D visualization of urban lighting also has the ability to display and query 3D real landscapes, but it is still based on 2D GIS data structures. In the 3D visualization window, if you use the mouse to click on an object in the window, if you want to know which object in the 3D space, the 2D mouse position needs to be backcalculated to the coordinates of the building surface in 3D space, and Get related attribute information from the 2D GIS data structure.
By linking 3D urban lighting information with a 2D database, you can perform a series of part analysis and query operations, such as 3D coordinate query, building property query, section drawing, and editing of graphics and attributes.
4 Conclusion The introduction of digital lighting is an inevitable outcome of global informationization. Its long-term strategic goal needs to be achieved through the joint efforts of all mankind. At the same time, the construction and development of digital lighting will accelerate the pace of global informationization, greatly change people's lifestyles, and create huge social wealth, making great contributions to the development of human society. In the information society of the 21st century, the development and construction of digital lighting must rely on the spatial combination of spatial information technology and 3S technology, data warehouse technology, computer network technology and 3D visualization technology, and can be truly integrated with its ultimate service goal. The combination of these technologies and service goals enables seamless integration between the various subsystems in the digital city, ultimately enabling digital lighting.
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