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

LEE NN Se DE Ces = == Seo SOR e Lo uuu ooo eee es = ATUM, bez SS Figure 3. The predictor is seen in use over a Digital Terrain Map representing the North Atlantic. The predictor shows future position based on current velocity inputs. The tails of the predictor show the path through the data space. Variations on the flight metaphor are other more constrained vehicles. These typically limit the freedom in some way that is suitable to some application. The key aspect to these metaphors is that the user feels that he or she is controlling a vchicle which can be used to explore the terrain (or other data space). The viewpoint is fixed to a vehicle which can then be driven around the environment. Bicycles in virtual environments are an example of this metaphor. Another is a treadmill used to simulate architectural walkthroughs (Brooks, 1986). 3. DATA MANIPULATION IN 3D The problems of data manipulation and viewpoint manipulation both involve six degree-of-freedom task performance. It takes three numbers to position an object in space and three more to specify its orientation. There are many solutions to the problems of 3D object placement, including virtual turntables (Evans et al, 1981), or virtual trackballs (Chen et al, 1988) whereby the mouse is used to control a set of higher level widgets which control rotations and translations. We have had considerable success using the Bat, described above for free object placement. However, in many GIS and CAD operations we find that it is better to used constrained placement. Often the user wishes to only manipulate one degree of freedom at a time, a rotation about a particular axis, or a single axis translation. Therefore, whereas we use the Bat extensively for viewpoint manipulation, we generally use a conventional mouse for object placement in the applications we are currently working on. 4. THE FLEDERMAUS SYSTEM We (Mark Paton and myself) are currently building a prototype 3D Geographical Visualization System at the University of New Brunswick that incorporates many of the advanced interaction techniques talked about in this paper (it is called Fledermaus). Our primary use of the flying technique is in a data visualization and editing system for oceanographic research. This enables users to fly over a digital terrain map represented in thinned wire frame form, The thinning is necessary because it is impossible to render the entire surface at the highest resolution and at a reasonable upgrade rate. As soon as the user stops flying, the surface fills in two steps: a medium resolution step and the highest resolution step. The idea is to keep adding information to the user and to fill in the otherwise unacceptable delay required to compute a fully rendered high resolution image (on our current IRIS Crimson VGX™ it takes 16 seconds to render a 2000x2000 digital elevation model). In order to make a high quality video of a flyby it is only necessary to hold down a different button on the Bat and from that time forward the sequence of viewpoints is recorded while flying. These viewpoints are later used to generate high resolution frames which are captured one at a time on our Panasonic LQ4000 laser disc recorder. The videos we have made in this way (using previous versions of the system) have appeared in the Canada pavilion at the recent Seville World's fair, on Canadian and German National Television as well as at numerous scientific and technical conferences. We are currently adding Georeferencing, to the visualization system and it now has support for multiple objects. This enables us to, for example, compare two different DEMs of the same surface, by co-registering them and moving them up and down with respect to each other. We have also recently added support for closed polygon meshes with the goal of visualizing schools of fish in the water column. We are currently investigating various techniques for stereo visualization and by the time this paper is presented should have stereo movie capabilites. ACKNOWLEDGMENTS I gratefully acknowledge the support and assistance of Dr. Larry Mayer who has been instrumental in encouraging the practical application of laboratory ideas. The research described here has been primarily funded through NSERC grants. REFERENCES Brooks, F.P. "Walkthrough - A Dynamic Graphics System for Simulating Virtual Buildings," Proc 1986 Workshop on Interactive 3D Graphics, F. Cro pp-$ Chapma Prec Virt Con Syn Can Chen, M Inte: Con No. Connor, D.C Dim Intei of C Evans, K Val of fr Vol. Gibson, Perc Gleicher Cam Sigg Mackinl. "Raf 3D. Sigg Phillips, "Au mani Grap Marc

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