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:: [Thursday, June 9, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

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

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: DIGITAL PHOTOGRAMMETRIC SYSTEMS AND THEIR INTEGRATION WITH GIS IAN DOWMAN

Document type:: Monograph

Structure type:: Chapter

It can also be concluded that full automation is still a distant goal, computer assistance can play an important role in many applications but the results achieved by the analytical power of the human operator cannot yet be reproduced with sufficient success to remove the operator from the process of feature extraction and object recognition. 4. Integration issues It is now widely recognised that more information can be obtained from imagery if data from several sources can be used. In order to use such techniques it is essential that these varied images be registered into a single co-ordinate system. Several examples have been quoted above. The image data also has to be used with map data or other data in vector form. To make use of this potentially vast source of data automation has to be used to synthesise the data and extract useful information. For example in the process of extracting features the support of a GIS is becoming essential, a number of methods under development for change detection require the use of existing information to help identify change. In a system for detecting changes in forest under development at UCL under contract to Earth Observation Sciences, edges extracted from imagery are compared to boundaries from maps in order to determine where change has, or has not taken place. In the top down method of feature extraction information about the objects is required and can come from a GIS. Ehlers (1994) identifies a number of issucs for investigation: data models integrated classification procedures; integrated error models; automated registration and map revision; integration with modelling techniques. These are currently the active arcas of research. 5. Validation issues The concept of accuracy is well established in the evaluation of photogrammetric data. There is no problem in establishing the accuracy of co-ordinates derived from imagery as long as control in the form of check points is available. Moreover the accuracy is usually related to the scale at which a map is produced. Once data from different sources is merged the origin may be lost and if data or images of different scales are merged then assumptions may be made which are not valid. For this reason data should be given an attribute which indicates its source and accuracy. Little effort has been made to do this at present although 342 work has been done to assess problems caused by generalisation at different scales (Jaoa, 1994). In the area of Radar data which has been geocoded products are produced to indicate certain aspects of accuracy. A pixel area map, also called an energy map, can be produced to indicate the surface area of a pixel when recorded, thus allowing correction for slope effects to be made by the scientist who is interpreting the data. Layover and shadow maps can also be produced (Schrieir, 1993), Error budgets are also produced with geocoded data which include an assessment of the accuracy of the DEM used for the geocoding. At the Remote Sensing Institute of the European Union's Joint Research Centre at Ispra, a geophysical processor is being developed which aims to provide an application scientist with all the information, and tools to use that information, to allow accurate interpretation of the data. 6. Conclusions Digital photogrammetric systems are now established as production tools although the economic advantages are not yet well established. Photogrammetric software is also available on digital image processing systems although care must be atken in using this and accuracy assessments made. The use of the latter systems with GIS enables data derived from remotely sensed data to be directly passed to the GIS and this offers significant avantages in data acquisition. The big break through will be when automation can be applied as a production tool. At the moment this only applies to elevation models and automatic feature extraction and model orientation is still a very active research area. As these new algorithms are being developed and incorporated into digital systems it is important that quality is considered and validation techniques built in. References Ahac A. A., Defoe R., Wijk M. C. van (1992); "Considerations in the Design of a System for the Rapid Acquisition of Geographic Information', PE&RS, Vol. 58, No. 1. Benny A. H. (1981); 'Automatic Relocation of Ground Control Points in Landsat Imagery’, Paper presented at a RSS society conference on "Matching remote sensing technologies and their applications", London, 16-18 December, 1981.

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