Object-fate analysis - spatial relationships for the assessment of object transition and correspondence
In the near future several new highest resolution, next generation satellites will be launched with panchromatic half-meter resolution imagery, e.g. WorldView 1 and 2. The ever increasing supply of high-resolution imagery seeks for adequate, i.e. more eff
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E. Schöpfer, S. Lang, F. Albrecht Centre for Geoinformatics (Z_GIS), Salzburg University, Schillerstr. 30, 5020 Salzburg, Austria - (elisabeth.schoepfer, stefan.lang, florian.albrecht)@sbg.ac.at
ABSTRACT: In the near future several new highest resolution, next generation satellites will be launched with panchromatic half-meter resolution imagery, e.g. WorldView 1 and 2. The ever increasing supply of highresolution imagery seeks for adequate, i.e. more effective, more automated and reliable methods for image processing and interpretation. At the interface of geographic information science and remote sensing, object-based image analysis methodologies provide a solid basis for exploiting imagery more intelligently. Working with image objects enables (1) single feature, specific information extraction, (2) performing complex classifications and multi-scale representations and (3) spatial analysis and modeling. However, deriving image objects from various sources and in different scales implies the problem of generating inconsistent boundaries. To specifically address this challenge, a tool called LIST (landscape interpretation support tool) is used, which, based on a straight-forward principle, analyses the spatial relationships of image objects, i.e. their correspondence and their changes over time. The chapter presents a methodological discussion and preliminary results from an ongoing study on ‘object fate analysis’ (OFA). OFA means the investigation of object transition (change over time) or object correspondence (different delineations or representations). The concept and the application of OFA are illustrated by two case-studies representing both aspects. The first one carried out in medium scale uses Landsat TM and ETM imagery and shows an example of performing change assessment as well as object-based accuracy assessment. The sec-
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E. Schöpfer, S. Lang, F. Albrecht
ond fine-scale study is based on SPOT 5 scenes and demonstrates how object correspondence can be assessed on two different object representations, machine-based segmentation and manual delineation.
Introduction Landscape changes through time With increasing awareness of sustainable usage of land, the preservation of cultural landscapes and the protection of the environment, both detecting and assessing changes become ever more important. European landscapes, shaped and managed over time, reveal a complex mosaic of land uses from cultivated to natural lands over a large geographic area. Changes in these landscapes are driven by inter-annual climate variability or long-term climatic trends, vegetation succession, natural disturbances, and of course, human land use (Schöpfer, 2005). In many areas of the world, socioeconomic and political factors induce and influence prevailing land use and land cover structures (Croissant, 2004). On satellite imagery, resulting changes are often acute and recognizable, though sometimes subtle and difficult to tell from noise. Analyses of changes in the landscape patterns are based on where the changes occur, th
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