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:: [Tuesday, June 7, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Session D-2 WG II/2 - Hardware and Software Aspects of GIS - Part A]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [3D] VIRTUAL GIS, A NEW REALITY By Nickolas L, Faust [...] Dharmajyoti Bhaumik [...] Ryan Woodard [...] Dung Vu [...]

Document type:: Monograph

Structure type:: Chapter

generated for a specific user view pyramid. The ray tracing technique must be able to decide which terrain or object polygons are intersected by initial rays or reflected rays. The search through all possible polygons for each ray is very time consuming. Many optimizations are used to reduce the number of intersections that must be calculated. A ray traced image may show very realistic effects such as reflections off of shiny surfaces, and generally is the type of image that is used in movie sequences. Inverse ray tracing is also popular in rendering. In this case instead of tracing a ray from the source until it intersects the terrain and finds its way into the view pyramid, the ray is cast from the viewer's eye, through image pixels in the imaging plane, and onto the terrain. This technique must also look for the intersection of the ray with the terrain polygons, but much fewer rays have to be cast. The terrain reflectance properties are assumed to be lambertian, in which for a given source ray, reflection occurs in all directions. Multi-bounce scattering is not easily accommodated within inverse ray tracing. IV. GTRI RENDERING APPROACH GTRI has developed a generic C rendering approach using the methodology of data base to screen rendering as described above. This technique implements photo texture mapping for both terrain and objects, can handle arbitrarily large spatial databases, incorporates antialiasing techniques for motion rendering (simulation), and runs in near real time (approximately 10 seconds) on a Sun SPARC 1 class workstation. Dynamic indexing into multiple levels of database resolution creates appropriate background fuzziness and antialiasing while reducing the total number of polygons to process. Image data or GIS feature layers may be draped over the terrain, giving a user the capability to dynamically see raw or analyzed information in a natural perspective. Using 118 a graphical user interface (GUI) a user may navigate throughout the database interactively, evaluating dynamically the visibility of certain features from his autonomous path. The perspective images of the spatial data set provide the ability for the user of the system to totally immerse himself within the spatial data base with ultimate free movement. The scenes that are created as the user moves are high quality, detailed, views of the spatial data set. The user is truly immersed into a virtual spatial data set using a Virtual GIS (VGIS). As the speed of rendering and display increases with the Joy’s Law increase in computing power , and as more of the process is implemented in parallel, full real time immersion is possible. While virtual immersion within the spatial data set is practical in the near term (1 to 2 years), the speeds for typical GIS spatial analysis functions should also be increasing. Thus, a user might place himself on a hillside and watch a rainstorm drop water into a watershed (a graphical illustration of a meteorology model), watch as the water finds its way into streams (as modeled by watershed runoff models), and see the river rise and create flood hazards. This is the very beginning for the merger of modeling, GIS, and visualization. V. REALTIME GIS INTERFACE In addition to the ability to immerse oneself within spatial data, a user must also be able to perform the natural GIS query functions and dynamically see the results of GIS analysis. The query function is implemented with the dynamic movement control structure of the view model. All interaction occurs with the rendered image. The user can place himself high above the database and essentially see a two dimensional view of the spatial data, or he can zoom into the data to view it from a specified view point point retrie coord and t GIS Wher avail: origit layer: such terrai of the the lz imag: with ‘ infori persp corre river, pick « VI. T C Geor; Comr game of Ge Villas plann const set ba foot maps. parki These attrib On the were build of the the b road : inforr was | of ev buildi were could obscu

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