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Usability evaluation of centered time cartograms / Rehmat Ullah in Open geosciences, vol 8 n° 1 (January - July 2016)  

Public [article]  inOpen geosciences > vol 8 n° 1 (January - July 2016) . - pp 337 - 359 Titre : Usability evaluation of centered time cartograms Type de document : Article/Communication Auteurs : Rehmat Ullah, Auteur ; Eskedar Zelalem Mengistu, Auteur ; Corné P.J.M. Van Elzakker, Auteur ; Menno-Jan Kraak, Auteur Année de publication : 2016 Article en page(s) : pp 337 - 359 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] cartogramme [Termes IGN] convivialité [Termes IGN] oculométrie [Termes IGN] Pays-Bas [Termes IGN] réseau ferroviaire [Termes IGN] temps [Vedettes matières IGN] Géovisualisation Résumé : (auteur) A time cartogram visualizes travelling-times between locations. It replaces the geographic distance by time distance and distorts the underlyingmap accordingly. By distorting themap, time cartogramsmay give a more intuitive and clear picture of travelling-times. The distortion of the map, however, can make time cartograms harder to recognize and use. Although cartograms are becoming widespread in use, very little is known about their usability. This study focuses on the usability of centered time cartograms: time cartograms that visualize travellingtimes from a fixed starting location to other destinations in a region. We created several centered time cartograms to answer spatio-temporal questions related to the Dutch railway network. Two experiments were performed: a laboratory test and an online survey. In the laboratory test, we used eye-tracking, thinking aloud, and video-recording to compare four different designs of centered time cartograms to find out which one (or combination) of these performs better in answering spatiotemporal questions and thus, to establish a favorable design strategy for these cartograms. In the online survey, centered time cartograms were evaluated against a geographic and schematic map for accuracy, response time, and preference. The first experiment suggested that among various designs, the centered time cartogram with emphasized railroads is the most preferred design and the centered time cartogram without railroads is the least preferred. The second experiment indicated that overall, centered time cartograms perform better than the two other solutions in performing spatio-temporal tasks, particularly when the task has a dominant time-related component. Numéro de notice : A2016--069 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1515/geo-2016-0035 En ligne : https://doi.org/10.1515/geo-2016-0035 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84415 [article]

An alternative method to constructing time cartograms for the visual representation of scheduled movement data / Rehmat Ullah in Journal of maps, vol 11 n° 4 ([01/08/2015])  

Public [article]  inJournal of maps > vol 11 n° 4 [01/08/2015] . - pp 674 - 687 Titre : An alternative method to constructing time cartograms for the visual representation of scheduled movement data Type de document : Article/Communication Auteurs : Rehmat Ullah, Auteur ; Menno-Jan Kraak, Auteur Année de publication : 2015 Article en page(s) : pp 674 - 687 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] carte thématique [Termes IGN] cartogramme [Termes IGN] distance kilométrique [Termes IGN] durée de trajet [Termes IGN] méthode des moindres carrés [Termes IGN] migration pendulaire [Termes IGN] Pays-Bas [Termes IGN] réseau ferroviaire [Termes IGN] transformation affine Résumé : (auteur) In a cartogram, the map elements are purposely modified with respect to an attribute. A time cartogram is a type of cartogram in which the geographic-distance between locations is replaced by a time-related attribute such as travelling-time, deforming the geography accordingly. This study concentrates on centred time cartograms that visualize travelling-times from a fixed starting location to other locations in the region. Several methods to construct time cartograms have been proposed, however these methods are not entirely satisfactory. In particular, none of them describes how to deform both the network and the map's boundaries based on travelling-times, which is necessary to maintain recognizability. In many cases, homeomorphism and topology are not maintained. The resultant maps from such methods are highly deformed and are difficult to read. Some of these methods are computationally demanding, while the procedures of others are not fully described. We present a method to construct time cartograms for the visual representation of scheduled movement data using the Dutch railways network as a case study. The method was developed by approaching the construction of time cartograms as a two-step process. In the first step, vector calculus is used to displace the train stations according to travelling-times from a fixed starting station. In the second step, moving-least-squares based affine deformation is applied to deform the railroads and the map's boundaries accordingly. To enhance understanding, concentric circles are drawn from the starting station to depict travelling-times. The method maintains homeomorphism and topology and yields time cartograms that are easily recognizable. Numéro de notice : A2015-541 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/17445647.2014.935502 En ligne : https://doi.org/10.1080/17445647.2014.935502 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77518 [article]