KARTOGRAFISCH TIJDSCHRIFT
2OOO-XXVT-4
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Summary
J.K. Rad - The accuracy of classified maps.
Keywords: thematic mapping, Classification of quantitative
data, visualisation
Classified choropleth maps are used both in order to communicate
particular known geographies and to explore unknown geograph-
ies. In both cases, it is important that information about the Clas
sification accuracy is given. Using an accurate classified map re-
duces the probability that the map enhance an impression of geo-
graphical dijferences that only to a small extent is present in the
data, or that the map hides dijferences that indeed is present in
the data. If users of a GIS or cartographic Software are informed
about how accurate the current Classification is, than they are
better equipped in making maps functioning as sources for
geographical knowledge rather than geographical nonsense.
Resume
J.K. Rod - L 'exactitude des cartes classifiees.
Mots-cles: cartographie thematique, Classification des donnees
quantitatives, visualisation
Les cartes choroplethes servent tout autant decrire qudecou-
vrir les structures de l'espace. Dans les deux cos il est important de
fournir des indications sur la marge d'erreur des classifications uti-
lisees. L 'utilisation d'une Classification statistiquement precise re-
duit le risque de creer des dijferences geographiques qui ne seraient
pas presentes dans les donnees oü d'effacer des dijferences reelles
qui seraient presentes. En infiormant les utilisateurs des SIG ou de
programmes de cartographie sur la precision des classifications
qu 'ils utilisent on contribuera a leur fournir des outils capables de
creer des connaissances plutot que des non-sens geographiques.
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