树图是一种实用的层次数据可视化方法,由于其数据属性和分析任务具有多样性,单种树图布局算法难以满足各层数据的显示需求.文中介绍了Slice and Dice,Squarified,Pivot-by-middle,Pivot-by-size,Pivot-by-split-size,Strip,Spiral和Orde...树图是一种实用的层次数据可视化方法,由于其数据属性和分析任务具有多样性,单种树图布局算法难以满足各层数据的显示需求.文中介绍了Slice and Dice,Squarified,Pivot-by-middle,Pivot-by-size,Pivot-by-split-size,Strip,Spiral和Ordered-Squarified 8种典型的矩形树图布局算法,给出了评价它们的6项性能指标定义,具体包括平均长宽比、连续性、可读性、平稳性、平稳的平衡性和距离相关性.通过实验,采用这6项性能指标对8种算法进行了比较分析,给出实验和分析结果.同时提出了多种布局算法混合使用的优化方案,并进行了优化后的指标分析,其结果可为树图布局算法的选择提供参考.展开更多
This paper describes a broad perspective of the application of graph theory to establishment of GPS control networks whereby the GPS network is considered as a connected and directed graph with three components.In thi...This paper describes a broad perspective of the application of graph theory to establishment of GPS control networks whereby the GPS network is considered as a connected and directed graph with three components.In this algorithm the gross error detection is undertaken through loops of different spanning trees using the "Loop Law" in which the individual components Δ X, Δ Y and Δ Z sum up to zero.If the sum of the respective vector components ∑X,∑Y and ∑Z in a loop is not zero and if the error is beyond the tolerable limit (ε>w),it indicates the existence of gross errors in one of the baselines in the loop and therefore the baseline must be removed or re_observed.After successful screening of errors by graph theory,network adjustment can be carried out.In this paper,the GPS data from the control network established as reference system for the HP Dam at Baishan county in Liaoning province is presented to illustrate the algorithm.展开更多
文摘树图是一种实用的层次数据可视化方法,由于其数据属性和分析任务具有多样性,单种树图布局算法难以满足各层数据的显示需求.文中介绍了Slice and Dice,Squarified,Pivot-by-middle,Pivot-by-size,Pivot-by-split-size,Strip,Spiral和Ordered-Squarified 8种典型的矩形树图布局算法,给出了评价它们的6项性能指标定义,具体包括平均长宽比、连续性、可读性、平稳性、平稳的平衡性和距离相关性.通过实验,采用这6项性能指标对8种算法进行了比较分析,给出实验和分析结果.同时提出了多种布局算法混合使用的优化方案,并进行了优化后的指标分析,其结果可为树图布局算法的选择提供参考.
文摘This paper describes a broad perspective of the application of graph theory to establishment of GPS control networks whereby the GPS network is considered as a connected and directed graph with three components.In this algorithm the gross error detection is undertaken through loops of different spanning trees using the "Loop Law" in which the individual components Δ X, Δ Y and Δ Z sum up to zero.If the sum of the respective vector components ∑X,∑Y and ∑Z in a loop is not zero and if the error is beyond the tolerable limit (ε>w),it indicates the existence of gross errors in one of the baselines in the loop and therefore the baseline must be removed or re_observed.After successful screening of errors by graph theory,network adjustment can be carried out.In this paper,the GPS data from the control network established as reference system for the HP Dam at Baishan county in Liaoning province is presented to illustrate the algorithm.
