TU Eindhoven.
IEEE Trans Vis Comput Graph. 2011 Dec;17(12):2536-44. doi: 10.1109/TVCG.2011.202.
Flow maps are thematic maps that visualize the movement of objects, such as people or goods, between geographic regions. One or more sources are connected to several targets by lines whose thickness corresponds to the amount of flow between a source and a target. Good flow maps reduce visual clutter by merging (bundling) lines smoothly and by avoiding self-intersections. Most flow maps are still drawn by hand and only few automated methods exist. Some of the known algorithms do not support edge-bundling and those that do, cannot guarantee crossing-free flows. We present a new algorithmic method that uses edge-bundling and computes crossing-free flows of high visual quality. Our method is based on so-called spiral trees, a novel type of Steiner tree which uses logarithmic spirals. Spiral trees naturally induce a clustering on the targets and smoothly bundle lines. Our flows can also avoid obstacles, such as map features, region outlines, or even the targets. We demonstrate our approach with extensive experiments.
流图是一种专题地图，用于可视化物体（如人员或货物）在地理区域之间的移动。一条或多条源通过线连接到多个目标，线的粗细对应于源和目标之间的流量。通过平滑地合并（捆绑）线条和避免自相交，良好的流图可以减少视觉混乱。大多数流图仍然是手绘的，只有少数自动化方法存在。一些已知的算法不支持边缘捆绑，而那些支持的算法则不能保证无交叉流。我们提出了一种新的算法方法，该方法使用边缘捆绑并计算具有高视觉质量的无交叉流。我们的方法基于所谓的螺旋树，这是一种使用对数螺旋的新型 Steiner 树。螺旋树自然会对目标进行聚类，并平滑地捆绑线条。我们的流还可以避开障碍物，例如地图特征、区域轮廓，甚至是目标。我们通过广泛的实验展示了我们的方法。
