通过流线展示分类维度间的相关性，连接共享要素的类别。矩形高度代表各维度的取值大小，流线宽度代表关联强弱。
关系与相关占比与构成
用在线工具做一张冲积图 →It shows correlations between categorical dimensions representing them as flows, visually linking categories with shared items. Each rectangle represents a unique value in the selected dimension, its height is proportional to its value. Correlations are represented with curved lines whose width is proportional to their value.
在 RAWGraphs 里制作冲积图只要四步：①把 Excel / CSV 表格数据复制粘贴进工具；②在图表列表里选择「Alluvial Diagram」；③把左侧的数据字段拖到右侧对应的映射区（如维度、数值、颜色）；④在 Customize 里调颜色与标签，最后导出 SVG 或 PNG，SVG 还能放进 Illustrator 继续精修。全程数据只在浏览器本地处理，不上传。