Automated Responsive Thematic Mapping with Layout Guides
基于布局引导的自动化响应式专题制图
Arjen Simons, Sarah Schöttler, Wouter Meulemans, Kevin Verbeek, Bettina Speckmann
AI总结 提出首个算法框架,通过布局引导结构高效计算响应式专题地图,实现地图元素在不同显示尺寸下的平滑自适应,兼顾统计信息可读性与制图上下文。
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专题地图以视觉方式传达关于空间单元(如国家或州)的统计信息。它们必须平衡承载统计信息的地图元素的个体可读性与整体制图上下文。如今,大多数地图不再是静态图像,而必须灵活响应各种设备类型和显示尺寸。当前的响应式专题制图方法存在局限性:对从业者而言劳动密集,且通常依赖组合不连贯的视觉编码以覆盖不同设备类型。在本文中,我们首次提出一种算法框架,用于高效计算能平滑适应不同显示尺寸的响应式专题地图。我们框架的关键组件是布局引导:一种组合结构,编码了专题地图的两个基本方面。第一个方面是每个统计地图元素的视觉需求(至少其期望的宽度和高度),第二个方面是以地图元素相对位置形式呈现的制图上下文。我们的主要算法贡献是地图排列器,它接收视觉容器作为输入,并返回合适的布局引导。地图排列器以稳定且一致的方式实现:如果容器变化很小,布局引导也变化很小,且相同的输入容器总是产生相同的布局引导。要使用我们的框架,需要三个要素:$(1)$ 参考布局,对应于“理想”的专题地图,$(2)$ 所有地图元素的总体垂直和水平顺序(针对具有极端宽高比的容器的期望布局),以及$(3)$ 能够从布局引导构建专题地图的专题制图算法。我们在两种类型的专题地图上演示了我们的框架,即矩形和Demers面积图。
Thematic maps visually communicate statistical information about spatial units such as countries or states. They must balance the individual readability of those map elements that carry the statistical information and the overall cartographic context. Nowadays, most maps are not static images, but must flexibly respond to a range of device types and display sizes. Current approaches to responsive thematic mapping are limited: they are labor-intensive for practitioners and often rely on combining disjointed visual encodings to cover different device types. In this paper we introduce the first algorithmic framework to efficiently compute responsive thematic maps that smoothly adapt to different display sizes. A key component of our framework is the layout guide: a combinatorial structure which encodes the two essential aspects of a thematic map. The first aspect are the visual requirements of each statistical map element (at least their desired width and height), the second aspect is the cartographic context in the form of relative positions of map elements. Our main algorithmic contribution is the map arranger which takes a visual container as input and returns a suitable layout guide. The map arranger does so in a stable and consistent manner: if the container changes only a little, then so does the layout guide, and the same input container always results in the same layout guide. To use our framework, one needs three ingredients: $(1)$ a reference layout, which corresponds to the ``ideal'' thematic map, $(2)$ a total vertical and horizontal order for all map elements (the desired layouts for containers with extreme aspect ratios), and $(3)$ a thematic mapping algorithm that can construct a thematic map from a layout guide. We demonstrate our framework on two types of thematic maps, namely rectangular and Demers cartograms.