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

ition has aditional roach is zia Tech in flight ays been ning fast allowing interface ral er of ion IVE started to be used in practical GIS applications. Simulation techniques developed over a number of years by the flight simulation industry using specially designed hardware, are now becoming viable on general purpose hardware. The synergistic combination of these two worlds into a truly interactive’ virtual’ GIS is now becoming a reality. II. VISUALIZATION IN CURRENT GIS SYSTEMS Current generation GIS systems generally view, analyze, and perform functions on spatial data (vector/raster) is a top down two dimensional manner. Complex analyses may be performed on the spatial data variables using weighting indexes, proximity functions, and a variety of multi-layer models. Each of the source layers of information as well as the analysis result is usually shown as seen from above. In many cases visibility of one part of the spatial data set from another position within the data set becomes as issue that must be considered. Example questions might involve whether a strip mine area can be seen from a major scenic highway, or whether a company’s view from its building will be occluded by the proposed erection of another building between it and the ocean. Visibility is generally handled in one of two ways, terrain masking, and perspective viewing. For terrain masking, a number of line of sight calculations are made in all directions from the viewers position. A line of sight calculation normally involves the reading of the terrain and feature data along a particular direction from the viewer. If there are locations along this line of sight that are higher in elevation than other points along the line of sight but farther away, then some of the terrain will not be seen by the viewer. These seen and not seen areas in all directions create a terrain mask in which areas that can be seen from the viewer location are differentiated from areas that can not be seen. The areas that can not be seen are said to be masked by the terrain. 115 This is a two dimensional representation of a visibility index. Perspective viewing allows the calculation and display of exactly what will be seen from a particular viewpoint. The perspective presentation of spatial data mimics the way that the eye perceives what can be seen. A view can be calculated that presents a very natural and interpretable image to the GIS user. The image, depending on the quality of the input image and GIS data, may show exactly what the viewer will see from that location. GIS systems which include multispectral imagery along with topography and other GIS layers can be used to show for example, what can be seen from the top of Stone Mountain, near Atlanta if one looks to the north west. Images from satellite and aircraft can record information in the visible, (red, green," blue) ^parts of the electromagnetic spectrum. Thus, when these images are draped over the surrounding terrain, the view closely replicates the human's view from that location. Atmospheric haze can be added to the generated images, or one can look at the view as if no haze were present; for example, after a fall cold front passes through. Perspective views have been generated for a number of years to show the view from a given geographic position. In general, however, perspective views are only used as a presentation method for final results and are not used in the analytical process itself. One of the principal reasons for this is the time it takes to generate a realistic perspective image. We will show in this paper that if this rendering can be done in near real time with modern technology, the perspective view will become the most natural interface for many GIS applications.

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