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Symbolize map distortion with inscribed circles in polygons / Shipeng Sun in International journal of cartography, vol 2 n° 2 (December 2016)  

Public [article]  inInternational journal of cartography > vol 2 n° 2 (December 2016) . - pp 166 - 185 Titre : Symbolize map distortion with inscribed circles in polygons Type de document : Article/Communication Auteurs : Shipeng Sun, Auteur Année de publication : 2016 Article en page(s) : pp 166 - 185 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie [Termes IGN] carte en anamorphose [Termes IGN] cartogramme [Termes IGN] déformation géométrique [Termes IGN] polygone [Termes IGN] projection [Termes IGN] symbole graphique Résumé : (Auteur) For the representation of geographic information, the distortion resulting from map projections and transformations is unwanted but unavoidable. Identical circles systematically arranged on the Earth's ellipsoid have been extensively used to symbolize the map distortion. Despite their effectiveness and popularity, these circles are not explicitly associated with any specific polygons in the map, thus possibly impairing their relevance if the map-readers are interested in particular regions. More importantly, for the map transformation specifically targeting polygons such as the area cartogram, placing the circles completely within the polygons becomes necessary because two neighboring polygons in an area cartogram could have distinctive distortion characteristics. This paper proposes new computer algorithms to enable a map-distortion symbolization approach based on inscribed circles entirely contained in polygons either on a projected 2D plane or on the Earth's ellipsoid. These inscribed circles in polygons (ICIP) are rendered as a series of maximum or equal-sized circles that are spatially exclusive, that is, without overlapping. Compared with the systematically arranged identical circles, the ICIP give cartographers certain flexibility and a new option for the map-distortion symbolization. Two area cartograms and three map projections are provided as examples to illustrate their usage and possible contribution in different mapping scenarios. Numéro de notice : A2016--061 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/23729333.2016.1179863 En ligne : http://dx.doi.org/10.1080/23729333.2016.1179863 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84216 [article]

A perception-based color recommendation algorithm for hierarchical regions / Shipeng Sun in Cartography and Geographic Information Science, Vol 42 n° 3 (July 2015)  

Public [article]  inCartography and Geographic Information Science > Vol 42 n° 3 (July 2015) . - pp 259 - 270 Titre : A perception-based color recommendation algorithm for hierarchical regions Type de document : Article/Communication Auteurs : Shipeng Sun, Auteur Année de publication : 2015 Article en page(s) : pp 259 - 270 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] carte thématique [Termes IGN] contraste de couleurs [Termes IGN] couleur (rédaction cartographique) [Termes IGN] lisibilité perceptive [Termes IGN] visualisation cartographique Résumé : (auteur) The visualization of hierarchical and nested spatial regions remains a challenge to cartographers. Despite progress in computer algorithms for visualizing general hierarchical data, mapping spatial hierarchical regions, especially with static, noninteractive means, still requires considerable manual efforts. This paper proposes a two-step algorithm that can automatically recommend perception-based colors and help reveal the hierarchical structure embedded in nested regions. It first systematically sorts regions according to their contiguity and containment relations at multiple hierarchical levels. Then, perception-based colors are generated using the order of regions with the goal of maximizing differentiability between top-level regions while retaining the perceived uniformity of the bottom-level regions. With the coloring scheme recommended by this algorithm, the metric color differences among regions mathematically reflect their hierarchical positions and spatial relations. The resultant colors, therefore, can potentially help map-readers perceive the spatially constrained hierarchy structure built in nested regions. Numéro de notice : A2015-243 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2014.991424 En ligne : https://doi.org/10.1080/15230406.2014.991424 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76241 [article]

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