While many graph drawing algorithms consider nodes as points, graph visualization tools often represent them as shapes. These shapes support the display of information such as labels or encode various data with size or color. However, they can create overlaps between nodes which hinder the exploration process by hiding parts of the information. It is therefore of utmost importance to remove these overlaps to improve graph visualization readability. If not handled by the layout process, Overlap Removal (OR) algorithms have been proposed as layout post-processing. As graph layouts usually convey information about their topology, it is important that OR algorithms preserve them as much as possible. We propose a novel algorithm that models OR as a joint stress and scaling optimization problem, and leverages efficient stochastic gradient descent. This approach is compared with state-of-the-art algorithms, and several quality metrics demonstrate its efficiency to quickly remove overlaps while retaining the initial layout structures.
翻译:虽然许多图形绘制算法将节点视为点,但图形可视化工具通常将它们表示为形状。这些形状支持显示诸如标签之类的信息,或者用大小或颜色编码各种数据。然而,它们可能会在节点之间创建重叠,从而通过隐藏部分信息阻碍探索过程。因此,消除这些重叠以提高图形可视化可读性至关重要。如果没有由布局过程处理,重叠消除(OR)算法已被提出作为布局后处理方法。由于图形布局通常传达有关其拓扑的信息,因此重要的是OR算法尽可能保留其拓扑。我们提出了一种新颖的算法,将OR建模为联合应力和缩放优化问题,并利用高效的随机梯度下降。与最先进的算法进行了比较,几个质量指标证明了它的效率,可以快速消除重叠,同时保留初始布局结构。