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Journal ArticleDOI

Significance of accuracy in a gis for water resource analysis

01 Jan 1993-Canadian Water Resources Journal (Taylor & Francis Group)-Vol. 18, Iss: 3, pp 307-311
TL;DR: In this article, the accuracy of spatial databases in a geographic information system (GIS) has become a recent focus of GIS research and methods to measure accuracy, reduce input error and track error propagation are required to ensure valid output.
Abstract: Accuracy of spatial databases in a geographic information system (GIS) has become a recent focus of GIS research. Two types of errors exist in spatial data: positional and attribute. Methods to measure accuracy, reduce input error and track error propagation are required to ensure valid output. Sources of error have to be recognized and a level of accuracy assigned to the data. Often data layers are combined to produce new data with little regard to the accuracy of the input data. Data in a GIS are often represented as having a much higher precision than that at which they were collected. Users have to be made aware of the accuracy of the data they are working with and the precision of their GIS. Hydrologic modelling with GIS must take into account the accuracy of the data to produce accurate output. Scale must also be considered, i.e. single watershed or an entire drainage basin, as this affects the resolution of data collection. Examples are used when possible and relevant.
References
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Journal ArticleDOI
TL;DR: In this paper, two algorithms to reduce the number of points required to represent the line and, if desired, produce caricatures are presented and compared with the most promising methods so far suggested.
Abstract: All digitizing methods, as a general rule, record lines with far more data than is necessary for accurate graphic reproduction or for computer analysis. Two algorithms to reduce the number of points required to represent the line and, if desired, produce caricatures, are presented and compared with the most promising methods so far suggested. Line reduction will form a major part of automated generalization. Regle generale, les methodes numeriques enregistrent des lignes avec beaucoup plus de donnees qu'il n'est necessaire a la reproduction graphique precise ou a la recherche par ordinateur. L'auteur presente deux algorithmes pour reduire le nombre de points necessaires pour representer la ligne et produire des caricatures si desire, et les compare aux methodes les plus prometteuses suggerees jusqu'ici. La reduction de la ligne constituera une partie importante de la generalisation automatique.

3,749 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a management perspective of Geographic Information Systems (GIS) from a geocarto perspective, focusing on the management aspects of the GIS.
Abstract: (1989). Geographic information systems: A management perspective. Geocarto International: Vol. 4, No. 4, pp. 58-58.

907 citations

Book ChapterDOI
06 Dec 1989

118 citations

Book ChapterDOI
06 Dec 1989

88 citations