Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

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Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

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

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [WA-1 KNOWLEDGE-BASED TECHNIQUES/ SYSTEMS FOR DATA FUSION]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: A RULE-BASED SYSTEM FOR THE EXTRACTION OF CARTOGRAPHIC FEATURES FROM LANDSAT TM IMAGERY. M. Stadelmann, G. D. Lodwick

Document type:: Multivolume work

Structure type:: Chapter

163 Table 1: Spatial and Spectral Attributes of Features (after Avery and Berlin, 1985) Attribute Comments Size/ area Both relative and absolute size are important. Relative size is strongly scale dependent. Absolute size can be measured by counting pixels. Shape Sometimes sufficient to identify a feature, but difficult to calculate. A measure of compactness could be used as a shape measure. Colour Typical of certain objects but depends strongly on season, angle of illumination etc. Straight-forward to extract from the image. Pattern Spatial arrangements of objects are especially useful in identifying man-made features. Texture Refers to the coarseness or smoothness of features, but is strongly scale dependent. Site/ association Important for contextual information, but can only be defined in conjunction with already identified features. Manual image interpretation usually proceeds systematically from feature category to category, as outlined above, and within these categories in a hierarchical fashion from more general descriptions to more specific details (Estes, 1977). Part of such a hierarchy is shown in Figure 2. In order to allow for a straightforward integration of interpreted features into a GIS, the automated system should solve its tasks in an equally systematic way. Maintaining a hierarchy is especially important, because spatial attributes, such as relative size, texture and pattern are strongly scale dependent. Urban Residential Commercial Industrial Transportation main road subsidiary road Figure 2: Image Interpretation Hierarchy Comprising Four Levels 3.2 User Requirements In order to facilitate the interpretation of remote sensing data, an expert interpretation system should be able to extract accurately and consistently resource features belonging to the six categories (a) to (f) outlined in Section 3.1. When prompted by the user, it should be able to interpret an image according to: (a) Feature (e.g. identify all roads; is feature X a road), (b) Feature attribute (e.g. show all small features), (c) Feature location (e.g. what is the identity of the feature at location x, y), (d) Relationships between features (e.g. what features are next to feature X), (e) Combinations of these queries (e.g. identify all small features next to feature X). Quality control, or an assessment of the accuracy of information, is an important aspect whenever data are integrated into a GIS data base. It is therefore necessary to have a confidence value associated with an identification, which gives an indication of the reliability of an interpretation. In addition, data validation procedures should be available so that invalid data can be rejected by the system, before the interpretation process begins. One reason expert systems have become attractive for the solution of complex tasks is their ability to interact with the user by using a human-like interface to explain system reasoning. A successful image interpretation expert system should therefore possess at least an explanation facility and, if possible, a natural language user interface. Interactive screenwork is one of the most popular and user friendly methods of image manipulation and analysis. The user of an automated image interpretation system should be able to select regions by placing a cursor on the image. Similarly, results should be displayed on the screen. To facilitate the integration of these results into a GIS, the identity of the features, their coordinates, and any other relevant information should be stored in a compatible data structure, e.g. as map overlays, which correspond to the data categories outlined in Section 3.1 above. 3.3 System Requirements Modularity to allow easy expansion of the system, and portability to permit transfer between mainframe and microcomputers were selected to be the most important system design requirements. Image interpretation is a complex and many faceted topic, and it was considered impractical to develop a multi-purpose interpretation system in one design phase. If a prototype system with a limited problem domain is to be of any future use, then it has to be expandable to a wide variety of applications.

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