Now available on Project MUSE…
Cartographica
Volume 50, Number 2, Summer 2015
Regionalization of Youth and Adolescent Weight Metrics for the Continental United States Using Contiguity-Constrained Clustering and Partitioning
Samuel Adu-Prah and Tonny J. Oyana
Contemporary spatial data collection techniques, analyses, and presentations have created new opportunities for public health analyses that sometimes render existing administrative and statistical boundaries unsuitable. This article presents an applied algorithm, regionalization with dynamically constrained agglomerative clustering and partitioning (REDCAP), to create regions other than pre-defined regions. The regions created in the study were based on the weight of youth in the continental United States. The REDCAP algorithm incorporates a spatial contiguity restriction to create regions with the same characteristics and value. The regions created overcome the existing challenge in cartography in which administrative and statistical regions are often used in presenting results. The study generated 10- and 25-class regions that reflected high and low obesity prevalence among US youth without using existing county and state boundaries. The results revealed new insights about regions comprising counties identified as having high obesity prevalence. Some of the counties identified in the established regions interestingly have not been recorded as at risk for high obesity prevalence in previous studies. A crucial advantage of the approach is that it minimizes the bias contained in existing administrative and statistical regions, a challenge in cartography. Furthermore, the approach effectively creates regions based on a specific theme and objective function.
POI Pulse: A Multi-granular, Semantic Signature–Based Information Observatory for the Interactive Visualization of Big Geosocial Data
Grant McKenzie, Krzysztof Janowicz, Song Gao, Jiue-An Yang, and Yingjie Hu
The volume, velocity, and variety of data that are now becoming available allow us to study urban environments based on human behaviour with a spatial, temporal, and thematic granularity that was not achievable until now. Such data-driven approaches open up additional, complementary perspectives on how urban systems function, especially if they are based on user-generated content (UGC). While the data sources, such as social media, introduce specific biases, they also open up new possibilities for scientists and the broader public. For instance, they provide answers to questions that previously could only be addressed by complex simulations or extensive human-participant surveys. Unfortunately, many of the required data sets are locked in data silos that are accessible only via restricted APIs. Even if these data could be fully accessed, their naïve processing and visualization would surpass the abilities of modern computer architectures. Finally, the established place schemata used to study urban spaces differ substantially from UGC-based point-of-interest (POI) schemata. In this work, we present a multi-granular, data-driven, and theory-informed approach that addresses the key issues outlined above by introducing a theoretical and technical framework to interactively explore the pulse of a city based on social media.
Using Hachures to Construct a 3D Doline Model Automatically
Nai Yang, Lin Wan, Gui-zhou Zheng, and Jie Yang
All types of relief features are usually represented by a unified digital terrain model on 3D topographic maps. Few studies have considered the differences in relief characteristics and terrain complexity. Hachures are often used to construct the relief symbols on 2D topographic maps, but they are less used on 3D topographic maps. This article uses hachures to construct a 3D doline model and divides them into three types: outlines, ridge lines, and break lines. We present the extraction method for doline outlines, consider the rules of visual perception under different illumination conditions, and study the mathematical models for representing the morphological characteristics of the doline with regard to the following aspects: width, arrangement density, and grey value of hachures. Finally, we introduce a process for 3D modelling of dolines on the basis of the above discussion. Experimental results indicate that the proposed model achieves a good 3D visual representation of dolines. Furthermore, the proposed model can also be used as a reference for the creation of 3D models of other negative relief features.
Interactivity and Cartography: A Contemporary Perspective on User Interface and User Experience Design from Geospatial Professionals
Robert E. Roth
This article reports on a semi-structured interview study with 21 geospatial professionals to provide a contemporary snapshot of expert opinion on the design and use of interactive maps and map-based systems (treated together as “cartographic interfaces”). Interview questions were based on key themes regarding interaction discussed within cartography and across the related fields of human-computer interaction, information visualization, usability engineering, and visual analytics, enabling a comparison of the current states of science and practice regarding user interface (UI) and user experience (UX) design in cartography. The results are organized according to five broad topics germane to UI/UX design in cartography: (1) the meaning of cartographic interaction in both research and practice (what?), (2) the purpose of cartographic interaction and the value it provides (why?), (3) the times when interaction positively supports work/play and therefore should be provided (when?), (4) the way in which user differences impact the success of the cartographic interaction (who?), and (5) the opportunities for or limitations on cartographic interaction imposed by the computing device supporting the interaction (where?). The interview study is significant for two reasons: first, it charts current trends in interactive mapping from the perspective of expert professionals, a population often missed in quantitative cartographic scholarship, and, second, it enables a reflection on future trends in UI/UX design in cartography, both those resulting from existing gaps between science and practice and those arising from emerging conceptual and technological developments.
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Cartographica Online includes the complete archive of current and previously published articles going back to 1964 (issue 1.1), when Cartographica was known as The Cartographer. More than 165 regular and special issues, 1800 articles and reviews await you at this comprehensive resource.
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Posted by T Hawkins, UTP Journals