Showing papers on "Choropleth map published in 1990"
01 Oct 1990-Cartographica: The International Journal for Geographic Information and Geovisualization
TL;DR: This paper evaluates sequencing of choropleth maps via reaction time experiments with human subjects to reveal that subjects favor some form of sequencing, while formal experiments show no significant difference between traditional and sequenced maps for either information acquisition or memory.
Abstract: Modern computer technology provides cartographers with a host of new display potentialities not possible with traditional printed maps. One of these is sequencing, or the display of map elements in a particular order. This paper evaluates sequencing of choropleth maps via reaction time experiments with human subjects. Informal experiments reveal that subjects favor some form of sequencing, while formal experiments show no significant difference between traditional and sequenced maps for either information acquisition or memory. Since subjects find sequencing appealing and it does not appear to have negative effects on map learning, software developers may wish to consider including it as part of their cartographic display systems. Les cartographes ont acces, grâce a l'actuelle technologie informatique, a un eventail de nouvelles possibilites d'affichage jusque la inaccessibles avec l'impression des cartes traditionnelles. Une de ces possibilites repose sur l'affichage sequentiel d'elements cartographiques...
35 citations
TL;DR: In this article, the authors present a comparison of six map complexity measures (aggregation index, compactness index, boundary contrast index, fragmentation index and size disparity index) using 90 different choropleth maps.
Abstract: The complexity of a choropleth map has an important influence on its readability. Six map complexity measures (aggregation index, compactness index, boundary contrast index, fragmentation index, boundary index, size disparity index) described in literature are presented in this study. Correlation coefficients between these indices are calculated, using 90 different maps. It is shown that most of the measures are highly correlated and therefore redundant.Visual judgement of 13 maps by 28 subjects shows that four indices (aggregation index, compactness index, fragmentation index, boundary index) can serve as reliable indicators of map complexity. As a result, each of these measures can be used to compare pattern complexity among different maps. The fragmentation index seems to be the best choice in view of its simplicity and calculation ease.
28 citations
TL;DR: It is argued that the needs of users interested in analysis of spatially referenced data are poorly met by the 'mainstream' model for GIS that is often presented in the literature.
Abstract: In much the same way as a spreadsheet is more appropriate to some needs than a fully relational DBMS, many users interested in analysis of spatially referenced data have fairly unsophisticated requirements for extensive data storage or complex retrieval functions, and limited needs for topographic detail, cartographic accuracy or advanced map editing; however, they do require access to a wide range of statistical functions for data transformation, reduction and smoothing, multivariate analysis, and the modelling of spatial relationships. This paper argues that the needs of such users are poorly met by the 'mainstream' model for GIS that is often presented in the literature. A PC-based system, equivalent in GIS terms to the spreadsheet, is described. It integrates simple data structures, limited map creation and editing, a powerful range of standard and spatially orientated statistical functions, and the ability to interactively present results through chloropleth, contour, proportionate symbol, or...
13 citations
1 Jan 1990
TL;DR: In this article, numerical methods are presented that represent three different approaches to biogeographic problems: multivariate data analysis, spatial patterns, and phylogenetic tree reconstruction for historical biogeographical studies.
Abstract: Numerical methods are presented that represent three different approaches to biogeographic problems. The first approach is multivariate data analysis. The delineation of biogeographic “provinces” or areas is a type of descriptive analysis that can be accomplished by clustering faunal data (with or without spatial contiguity constraint) and drawing the resulting choropleth map. On the other hand, ecological biogeographers like to use ordinations of sampling localities and interpret the main axes of variation in terms of environmental gradients; canonical ordination, where a species presence or abundance data table and an environmental data matrix are both analyzed simultaneously, can be used with profit in this context. Secondly, the analysis of spatial patterns can help identify the type of spatial distribution of the biological material, both at the population and at the community level, while Mantel tests and other derived analyses make it possible to test hypotheses concerning causal factors possibly responsible for the observed spatial structures. Finally, phylogenetic-tree reconstruction methods, as well as other techniques, can be used for historical biogeographic studies; these include the study of taxa cladograms and of area cladograms.