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

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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:: [THP-2 GIS INTEGRATION]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: GIS-Guided Road Extraction form Satellite Imagery. J. Van Cleynenbreugel, F. Fierens, P. Suetens, A. Oosterlinck

Document type:: Multivolume work

Structure type:: Chapter

651 • A terrain model is useful to indicate plausible road tracks in the image data and provides constraints related to admissible slopes of lines. • The hydrography has obvious influences on the appearance of road structures. Roads often follow countour lines in valleys while minimizing the number of river crossings. • An existing roadmap can be used as a guide for image analysis to find analoguous roads and as a logical framework : new roads are usually connected to existing ones. We regard a GIS as a digital raster database consisting of layers of cartographic maps and RS data. It is assumed that the different data layers are registered in such a way that any two of them can be exactly (pixel-by-pixel) superimposed. To provide a smooth link between GIS and knowledge-based programming, an object-oriented environment for image understanding is used, [1]. It is implemented on top of the existing hybrid tool KEE, see e.g. [5]. Data sets from the GIS can be directly mapped to object classes in a KEE knowledge base (see Fig. Bl) (in KEE a set of related objects is called a knowledge base or KB). Possibilities to utilize iconic structures are provided by the image understanding environment. Expertise about road delineation is added as shown in the next sections. 3 GIS-guided extraction : three case studies Because of the inherent ambiguity of satellite images and because a variety of road networks does exist, each showing different scales of complexity, there exists a need for a problem solving strategy that progressively reduces the search space. To cope with this problem we start from generic models of road-network appearance and try to incrementally focus the attention in order to obtain optimal results (with regards to some objective function). This strategy has been called hierarchical search, [4]. 3.1 Exploiting LANDCOVER knowledge In the first case study, we deal with a generic network model of road appearances that has the following characteristics : • the network consists of straight roads • in general, these roads intersect perpendicularly • the landcover region is subdivided into repeating geometrical structures (such as rectangles) by the roads Typical landcover regions that show this kind of network patterns are forests in flat terrain (see Fig. L3) or desert areas being cultivated by irrigation projects (see Fig. L5). On high resolution satellite imagery, these roads are visible as line-like structures. The road network topology in such areas is related to practical considerations (e.g., accessibility).

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