Showing papers on "Choropleth map published in 1976"
1 Jan 1976
TL;DR: In this paper, a study was conducted to determine how people make judgments about the similarity of patterns on choropleth maps using different classing techniques and found that the decision-making process was influenced by both the similarities of the spatial distributions and the relative blackness of the maps.
Abstract: This study was conducted to determine how people make judgments about the similarity of patterns on choropleth maps Two sets of maps were prepared from the same data using different classing techniques Two groups of subjects were asked to select the two maps with the most similar patterns from triads of maps in their respective sets Although it was anticipated that the Ss (subjects) would consider only the similarity of the distributions, they also used relative blackness as a major decisionmaking criterion The classing techniques (equal interval and Jenks-Caspall method) used to produce the sets of maps did not have a significant effect on the Ss ability to judge similarity, as the resulting maps differed only slightly Decisions on the similarity of the maps appeared to be influenced by both the similarity of the spatial distributions and the relative blackness of the maps
11 citations
1 Jan 1976
TL;DR: Choroplethic map patterns are affected by the number of class intervals on the map as discussed by the authors, and map attributes such as map blackness, aggregation, complexity, and contrast are significantly affected by number of classes.
Abstract: Choroplethic map patterns are affected by the number of class intervals on the map Four mathematically-defined pattern attributes—map blackness, aggregation, complexity, and contrast—are here compared when differing numbers of intervals are used to represent 17 different geographic variables using the Jenks-Caspall classing procedure Analysis of the map series shows that: (1) the attributes are significantly affected by the number of classes but at a decreasing rate as the number of classes increases; (2) pattern variability among maps of different distributions decreases with increasing numbers of classes These findings substantiate the contradictory relationship between map enhancement and map consistency Few classes provide emphasis or enhancement of map pattern, but a four-class map, for example, may be quite different than a three-class map of the same distribution Many classes result in a more stable representation of the specific distribution, but the characteristics of the map also differ les
10 citations
TL;DR: In this article, the main components of the multivariate map reading process are pointed out, including the perceptual interactions between the actual locations of map tones and the overall similarity between map patterns.
Abstract: Visual map comparison can supplement statistical analysis by providing information as to where and how spatial correspondence occurs. The associations that may be discovered are influenced by the nature of the map features being compared and the criteria used for making the comparisons. In this paper the author has tried to identify the elements of visual recognition that map readers use to associate or differentiate geographical distributions represented by choropleth maps. The main components of the multivariate map reading process are pointed out, including the perceptual interactions between the actual locations of map tones and the overall similarity between map patterns.
9 citations