Browsing by Subject "choropleth mapping"

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Access status: Open Access ,
Wybrane metody tematycznej wizualizacji kartograficznej
(Wydawnictwa AGH, 2005) Żukowska, Maria
Among many various cartographic visualization methods thematic maps are definitely standing out. One of them are cartogrammic mapping techniques, which are used to depict statistical surface with areal signs. Some phenomenon average intensity in spatial units boundaries they show. Two cartogrammic mapping techniques: choropleth and dasymetric mapping in the paper are discussed. Using cartogrammic methods numerical values either in discrete or continuous manner is shown. Usually cartogrammic techniques are used to present relative values, what is a simple consequence of being presented in reference to spatial units boundaries. In the paper the fact, that diversified reference units size can lead to distorted map perception is mentioned, what makes the reference units choice as one of the most essential problems. Apart from that some other problems that can influence the choropleth maps creation correctness are shown, among them rating ranges and color scale choosing. In the paper some analytic, graphic and iterative range constructing methods are presented. Also some choropleth mapping disadvantages are discussed, which the dasymetric mapping is decreasing. Several dasymetric techniques are described as well. Treating dasymetric method as one of the areal interpolation problems, especially in American literature, is mentioned.