Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Friday, June 10, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Joint ISPRS/GIS '94 Plenary V]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: ADVANCED 3D VISUALIZATION TECHNIQUES COLIN WARE

Document type:: Monograph

Structure type:: Chapter

ORS FOR ION ion and virtual me problem in > the viewpoint k where this is Ssurles, 1992), ions (Brooks, systems, and iting subsea or ) as well as cations. studying a six )n mouse input s like a mouse . The device tion (azimuth, ne studies we ed for object re recently we vays that allow metaphors for are based on | a conceptual e. Thus if the h the data, it is the data is on a the remainder y of different is employed in ra controllers. a Metaphor in viewpoint as if taphor requires f the virtual of the monitor. e) is placed at ne from this or. Cognitive ifficulty some lel. Ware and | differences in ted away from n hand motion ig. Physical al limitation of r impossible to riation on this a commands of e cameraman. 1992) explores he user control over the viewpoint in a manner which is similar to directing a cameraman to make a movie shot . Thus the director might request a cameraman to track a certain moving object, pan from object A to object B, or zoom in to a close-up. An even more ambitious approach is to have an autonomous smart camera which positions the viewpoint automatically to allow the user to concentrate on some other task (Phillips, et al, 1992). 2) World in Hand and Mechanical Metaphors. In the "World in Hand Metaphor" the viewpoint is changed by moving the object. Thus, to look at a displayed scene from the right hand side, the scene is rotated clockwise (as viewed from the top), like an object on a turntable. If a 6DF input device, such as the Polhemus™, or a SpaceBall™, is available then rotations and translations can be carried out simultaneously. As a method for changing the viewpoint the world in hand metaphor works well for single, reasonably compact objects. However, when the environment to be explored is a landscape or enclosed interior space, picking it up and moving it does not seem natural (it has poor cognitive affordances). There also exists a problem selecting the center of rotation. Especially when moving through an interior the metaphor clashes with the user's perception of being enclosed and the linkage of scene motion to hand motion is incongruous and difficult to grasp (Ware and Osborne, 1990). The World in hand metaphor is almost the opposite of the eyeball in hand metaphor; instead of moving his or her viewpoint the user imagines moving the object. Useful variants on the metaphor are such devices as the virtual turntable (Evans, et al, 1981), stirrer, or virtual sphere (Chen, et al, 1988) which transform the input from a mouse or digitizing tablet to give the feeling of direct manipulation of a graphical object. These devices tend to be easy to learn but not very flexible. Often they must be carefully customized to provided the range of movements required by the application. We are using a virtual turntable in an interface to a DEM visualization system for satellite imagery. 3) Functions and Smart functions. It is a common practice to control the viewpoint using common graphics library functions such as scale, translate and rotate. These functions may be controlled directly by the mouse or indirectly via sliders. We include this kind of interface for completeness although it does not embody the use of a consistent metaphor. A much more interesting use of (non metaphorical) functions is the point of focus zoom developed by MacKinlay, et al (1990). The implemented a zoom which corresponds to moving the viewpoint to the surface, halving the distance for each unit time. The also evaluated some complex compound viewpoint movements, for example, to zoom in on a particular 489 surface point and at the same time rotate so as to place the surface at right angles to the viewing direction. 4) Head Coupling and the Virtual Reality (VR) metaphor The VR metaphor involves coupling the perspective image to the user's head position so that, for example, to look at the far side of an object the user must walk around the object (Sutherland, 1968). This method uses the interface of everyday life but its affordances are highly restrictive, it only allows viewpoint manipulation within the range of head movements. To allow for greater flexibility it must be combined with other methods. It most naturally fits with the use of mechanical widgets (such as a virtual turntable) because they can be implemented as objects in the virtual world (Connor, et al. 1992). It is also possible to implement a localized form of VR using a conventional workstation an coupling the viewpoint to the measured eye position (Ware, et al, 1993) as shown in Figure 2. Head Tracking og vw \ | \ tereo Glasses Virtual Objects Figure 2. By coupling the perspective viewpoints for the two eyes to the measured head position of the observer and using stereo glasses it is possible to create a highly realistic localized virtual image. 3) Flying and virtual vehicle control Flight simulators have the rather inconvenient affordances of flying vehicles, problems such as stalling when the velocity is low are hindrances to arbitrary control of viewpoints. We have done extensive work towards making an easy-to-use velocity control interface for exploring 3D graphical environments. This which makes no attempt to model real flight dynamics but is designed to give a great flexibility in the control of viewpoint movements through environments which mostly consist of scientific data representations (Ware and Osborne, 1990). Predictive feedback can greatly enhance the user's sense of control (Chapman and Ware, 1990). The form of predictor that we have developed is illustrated in Figure 3. We use this system in making movies to convey information to others.

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