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1、Virtual reality technology,The main content,I OverviewII VR hardware and interaction devicesIII Virtual Reality and GIS networkIV Virtual reality technology develops V virtual environment modeling and tools VI development example: Virtual Campus Xianlin Campus of Nanjing Normal UniversityVII Prospec

2、ts and ProblemsAppendix: References,I Outline,Virtual reality is the development of computer technology is highly crystalline and is reflected in the various fields in the application process, including not only graphics, image processing, pattern recognition, network technology, parallel processing

3、 technology, artificial intelligence and other high-performance computing technology, but also involves mathematics , physics, communications, and even related to meteorology, geography, aesthetics, psychology and sociology.,I-I What is virtual reality,Virtual reality or virtual environment is gener

4、ated by a computer having spot feeling environment, it is a new interactive system.Virtual reality technology is essentially a highly realistic simulation of human vision in real life. Hearing. Action and other acts of interactive technology.Traditional information processing environment has been a

5、people adapt computer, while todays goal or idea is to gradually make computer adaptation and people called for the adoption of sight, hearing, touch, smell, and body, gesture or password, to participate in the information environmental treated to thereby obtain an immersive experience. This informa

6、tion processing system is no longer based on the one-dimensional digital space, but on a multidimensional information space. Virtual reality technology is a key technology to support this multi-dimensional information space.,I-II Virtual Reality Featurs,ImmersionInteraction Imagination,Immersion,vAn

7、 artificial computer generated virtual environment, this virtual environment is a three-dimensional digital models constructed by computer graphics, programmed into a computer to produce realistic virtual environment, allowing users to generate an immersive virtual environment visually the feeling,

8、which is a sense of virtual reality technology immersion (Immersion) or spot a sense of participation,Interaction,Model and the traditional three-dimensional animation and virtual reality are usually generated by CAD systems is not the same, it is not a static world, but an open, interactive,virtual

9、 reality environment can influence by controlling and monitoring devices or users Effects, which is the second feature VR, i.e. interaction (Interaction).,Imagination,Virtual reality is not just a demonstration of media, but also a design tool. It reflects the visual form designer ideas, such as whe

10、n the front cover of a modern building, the first thing you do is for the buildings structure, beautiful idea to do detailed, in order to make quantitative, you need to many design drawings, of course, these drawings only insiders understand, virtual reality can put this idea into a visible virtual

11、objects and environments, so that in the past only with traditional sand table design patterns upgrade to digital-per-view income that is perfection, greatly improving the quality and efficiency of the design and planning. This is the third category of VR has features that imagination (Imagination).

12、,I-III Virtual Reality classificaion,Desktop Virtual RealityImmersive virtual realityAugmented Reality of Virtual RealityDistributed Virtual Reality,I- IV The difference between virtual reality and three-dimensional animation,I-V Virtual reality technology used in the real world,Many game makers, in

13、 order to make the game more realistic character movements, often will use the motion capture system.Virtual reality technology use in the film.Example: MatrixDisplay of goods (such as home, appliances, etc.),II VR hardware and interaction devices,A typical system consists of virtual reality space d

14、ata acquisition system, the human data capture systems, three-dimensional display device, as well as three-dimensional control equipment and a computer system. Spatial data acquisition system, human data capture system in a virtual environment to establish space model; 3D display device, a three-dim

15、ensional control equipment belong to the same three-dimensional interactive equipment, design and manufacture of 3D interactive device superior performance is the key to virtual reality technology.,Spatial Data Acquisition System,Human data capture system,Computer SystemsSuper graphics workstations,

16、Three-dimensional control equipment,3D display device,Collection,Alternately,Spatial Data Acquisition System,Spatial data acquisition system to obtain timely spatial data through satellite remote sensing, aerial remote sensing and global positioning systems, and establishing an accurate and reliable

17、 virtual reality space environment. Remote sensing is an advantage of the inherent characteristics of electromagnetic radiation reflected from an object and through implementation of electromagnetic waves, there are technical environmental conditions and object recognition object.,Human data capture

18、 system,Human data capture device that can record the body of practical data and actions, including the body movements, facial expressions, physiological index, smell and voice.,Interactive 3D Equipment,Common 3D display device and stereoscopic helmet mounted display glasses.Helmet mounted display w

19、ith three-dimensional drawing techniques to produce two spaced apart perspective, and directly displayed to the user corresponds to the left and the right eye on two monitors. The new helmet-mounted displays are accompanied by magnetic position sensor, can measure the direction of the users line of

20、sight, so the scene can change as the users line of sight and make the appropriate changes.,Interactive 3D Equipment,A common feature of the three-dimensional space control device is capable of controlling at least six degrees of freedom (Degree of Freedom), corresponding to the three-dimensional ob

21、ject describing the width, height, depth, pitch (pitch) angle, rotation (yaw) angle and yaw (roll) angle. Common three-dimensional control device has data gloves, track ball, three-dimensional probe, three-dimensional and three-dimensional mouse control lever and the like.The emergence of the data g

22、love, virtual reality system provides a new interactive tool that can provide users with a very real and natural three-dimensional interactive tools.,High-performance computer systems,High-performance computer system processing technology includes data conversion and data preprocessing technologies;

23、 real-time, realistic graphics image generation and display technology; multidimensional information data fusion, data compression, and generate the database; multiple sound synthesis and sound space technology; including command recognition, voice recognition, and detect gestures and facial express

24、ions of information, including a pattern recognition; distributed and parallel computing, and high-speed, large-scale remote network technology.,III Virtual reality and networks, GIS,Virtual reality technology now combines the latest research results in various disciplines, including the results of

25、computer science, communication network technology, geographic information systems, remote sensing science and other areas. The main contents of this section:Virtual GISNetwork Virtual GISDistributed GISGeographical synergy,III-I Virtual GIS,Development of computer science and human-computer interfa

26、ce technology in graphics, especially the promotion of virtual reality technology for GIS provides a new analysis geoscience data and technology platform to explore issues, and promote the GIS technology with virtual reality technology and visualization fusion technology, expanding the multi-dimensi

27、onal GIS, three-dimensional GIS in particular connotation study provides new spatial data analysis models and new GIS application mode. Current international call this virtual reality technology and scientific visualization technology designed multidimensional GIS system called Virtual GIS system Vi

28、rtual GIS (VGIS).,III-II Network Virtual GIS presentation,Combined with the current direction of the virtual network is a GIS development. Combined with network technology, network virtual GIS not only for people to analyze spatial data and spatial problem solving network provided by the technology

29、platform, through immersive virtual reality model for people to interact through virtual geospatial offers the possibility, thereby for the study of virtual geographical environment provides an ideal platform.,Network Virtual GIS architecture,1.A GIS is a virtual network-based GIS, virtual reality s

30、ystem with the GIS Client-linking provides a simple spatial analysis or to analyze the results of GIS into virtual reality system to support virtual reality system data format, for virtual reality systems to observe;2. Another virtual GIS is based on a distributed virtual reality system, extend the

31、ability to support spatial data types in a virtual reality system, providing simple spatial analysis.,The overall structure of WEB virtual GIS,III-III GIS system architectures role in the network virtual 3.3 CORBA,CORBA is one of the mainstream computing platform for distributed objects, CORBA platf

32、orm to become widely accepted by the computer industry, and is fully open to the distributed network platform. CORBA is a distributed object-based design having scalability, security, load balancing and fault tolerance, real-time, special performance requirements for the design of distributed system

33、s provide a rational platform. CORBA-based network platform to design virtual GIS, by reusing the CORBA network structure and basic network services greatly simplify virtual difficulty GIS network architecture design based on virtual GIS CORBA allows the network to use more flexible network architec

34、ture.,CORBA-based naming service network VGIS system image concept map,-,III- IV VGE and geographic synergies,Virtual Geographic Environments, is an avatar-based multi-user distributed intelligent three-dimensional virtual environment, a digital geo-spatial phenomena and laws of a particular geograp

35、hical environment with multi-channel-aware expression, calculation and simulation, integrated management of the Earth can be used for multi-dimensional information and multimedia integrated publishing, interactive / innovative blend of style earth science research, and other distributed collaborativ

36、e planning, design and decision-making.,User avatar,In the virtual geographic environments, both user avatar can communicate face to face in the same virtual location. The incarnation as an expression of real users, and its source can contain visual, auditory and even taste a variety of information

37、sources, etc., so that the user has a sense of immersion can be immersive feel itself is a virtual geographic environments part. Seeing and hearing other information sources may be co-workers to communicate what the real attitudes and emotions, is an important part of communication between co-worker

38、s in virtual geographic environments, and analysis of geographic data in planning and decision-making also plays a very important effect.,AC Mode,For virtual geographic environment is not only a real geographical background, but also to provide a reliable platform for the exchange of information co-

39、workers are. To this end, we need more research on how to improve communication modes between people and enhance various exchanges avatar in virtual geographic environments between.Currently, in accordance with the timeliness of the exchange of classified- Non-real-time communication: e-mail and bul

40、letin board Instant communication: interactive, real-time, including the traditional two-dimensional scenes, three-dimensional scene, streaming media technology and integration mode.,IV The main development of virtual reality technology,VRMLXMLX3DJava3D,VRML,XML,地理实体,X3D,JAVA3D,In the virtual realit

41、y technology, VRML / GeoVRML, XML, X3D, GML and Java3D technology strengths complement each other, the use of graphical modeling capabilities VRML, XML internationalization, structured, modular features and powerful Java network programming language, together form a powerful virtual reality environm

42、ents.,IV-I VRML,In 1994, the first session of the International Internet Conference in Geneva, Switzerland, proposed to create a three-dimensional network interface to facilitate network transmission VRML.In 1995, VRML1.0 version launched.In 1996, based on the 1.0 version of the major improvements i

43、ntroduced in version 2.0, which adds interactive scenarios, multimedia support, collision detection.In 1997, after an assessment standards organizations, VRML2.0 become the international standard, and renamed the VRML97.,VRML simple example,sphere.wrl#VRML V2.0 utf8Shape # Define node contains two p

44、roperties appearance Appearance # Appearance properties material Material #material， emissiveColor 1 0 0 # Reflective material geometry Sphere # Geometric properties radius 1,IV-II XML,XML full name in English is Extensible Markup Language, the Chinese translation for extensible markup language. It

45、is an exchange standard by the W3C (World Wide Web Consortium) the promotion of structured information, and has been widely used. VRML adopt XML as the encoding of the main reasons is because with the international nature of XML, structured format and modular objects and other advantages. Has been c

46、learly established by the implementation of the XML specification, X3D XML-syntax is easy to be implemented without the need for a huge reverse engineering (reverse engineering).,XML and GIS,What role does XML play in GIS applications? We can use XML to define a query, in fact the traditional GIS qu

47、ery is no different, for example, can say, according to a user-specified area flooded analysis, and returns the result, the response message may be based on the results of the analysis in XML format the following graphic. The difference lies in the traditional way, geographical data and requests uni

48、fied XML queries included in a separate XML document, a response message also XML documents.XML support for custom tags, provides a powerful extension mechanism, which inevitably many unique mark appears GIS industry.,XML与GIS,OpenGIS Consortium (OGC) launched a timely GIS XML tag set GML (Geography

49、Markup Language), an XML application in GIS provides a good way of standardization, the industry has been supported by many companies.The use of XML, we can achieve many GIS tasks -Browse and generate images, such as SVG, VML and X3D formats;Data conversion can be performed, such as XSLT, Schema can

50、 be configured, such as DTD, XML Schema and the like; You can query data, such as Xpointer and XQL, etc., it can also be run on different platforms, such as PDA.,IV-III X3D,X3D full name is Extensible3D (X3D early name is called VRML-NG, VRML Next Generation). It is a scalable next-generation 3D gra