当事物或人从一个地点移动到另一个地点时，可以通过流向地图（Flow Maps）揭示出运动中的一些规律或现象。在tableau中使用makepoint和makeline函数则能生成流向地图。
1，创建以下数据源：可以复制到excel中，拆分成列；
From,From (Latitude),From (Longitude),To,To (Latitude),To (Longitude)
London,51.507351,-0.127758,Scotland,56.490669,-4.202646
London,51.507351,-0.127758,Wales,52.130661,-3.783712
London,51.507351,-0.127758,Spain,40.463669,-3.74922
London,51.507351,-0.127758,France,46.227638,2.213749
London,51.507351,-0.127758,Germany,51.165691,10.451526
London,51.507351,-0.127758,Belgium,50.503887,4.469936
London,51.507351,-0.127758,Netherlands,52.132633,5.291266
London,51.507351,-0.127758,Denmark,56.26392,9.501785
London,51.507351,-0.127758,Switzerland,46.818188,8.227512
London,51.507351,-0.127758,Italy,41.871941,12.56738
London,51.507351,-0.127758,Croatia,45.099998,15.2
London,51.507351,-0.127758,Slovenia,46.151241,14.995463
London,51.507351,-0.127758,Austria,47.516232,14.550072
London,51.507351,-0.127758,Czech Republic,49.817493,15.472962
London,51.507351,-0.127758,Poland,51.919437,19.145136
London,51.507351,-0.127758,Hungary,47.162495,19.503304
London,51.507351,-0.127758,Romania,45.943161,24.966761
London,51.507351,-0.127758,Greece,39.074207,21.824312
London,51.507351,-0.127758,Cyprus,35.126411,33.429859
London,51.507351,-0.127758,Turkey,38.963745,35.24332
London,51.507351,-0.127758,Finland,61.92411,25.748152
London,51.507351,-0.127758,Sweden,60.128162,18.643501
London,51.507351,-0.127758,Norway,60.472023,8.468946
London,51.507351,-0.127758,United States,37.09024,-95.712891
London,51.507351,-0.127758,Canada,56.130367,-106.346771
London,51.507351,-0.127758,Malaysia,4.210484,101.975769
London,51.507351,-0.127758,Singapore,1.352083,103.819839
London,51.507351,-0.127758,India,20.593683,78.962883
2，连接以上数据源，创建计算字段：起点MAKEPOINT()，终点MAKEPOINT()，路径MAKELINE()
双击【路径】生成流向地图，如2-1
3，以上函数仅2019.2以上版本支持。
