Tableau 简明教程
Tableau - Bump Chart
凸点图用于根据度量值，将两个维度相互比较。它们对于探索值在时间维度、地点维度或与分析相关的其他维度上的排名的变化非常有用。
A Bump Chart is used to compare two dimensions against each other using one of the Measure value. They are very useful for exploring the changes in Rank of a value over a time dimension or place dimension or some other dimension relevant to the analysis.
凸点图包含两个维度，其中包含零个或更多度量值。
The Bump Chart takes two dimensions with zero or more measures.
Creating a Bump Chart
使用 Sample-superstore（样品超级商店），计划查找产品运输方式与子类别变化之间的差异。为实现此目标，请执行以下步骤。
Using the Sample-superstore, plan to find the variation of ship mode of products with the variation of the Sub-Category. To achieve this objective, following are the steps.
Step 1 - 将维度 Sub-Category（子类别）拖放到“列”栏架中。此外，将维度 Ship mode（运输方式）拖到“标记”卡下的“颜色”栏架中。将图表类型保留为“自动”。将出现以下图表。
Step 1 − Drag and drop the dimension Sub-Category to the Columns shelf. Also drag the dimension Ship mode to the Color shelf under Marks card. Leave the chart type to Automatic. The following chart appears.
Step 2 - 接下来的，创建一个名为 Rank（排名）的计算字段。转到 Analysis（分析）→ Create Calculated Field（创建计算字段）。使用 Rank（排名）作为字段名称，并在运算区域中编写表达式 index()。这是一个内置函数，用于为分区中的当前行创建索引。单击“确定”，新字段将显示在度量值部分中。右键单击字段 Rank（排名），并将其转换为离散字段。
Step 2 − Next, create a calculated field called Rank. Go to Analysis → Create Calculated Field. Use Rank as the field name and write the expression index () in the calculation area. It is an inbuilt function that creates an index for the current row in the partition. Click OK and the new field will be visible in the measures section. Right-click on the field Rank and convert it to discrete.
Step 3 - 将 Rank（排名）拖到“行”栏架中。将出现以下图表，其中显示了维度 Sub-Category（子类别），其中每个运输方式均以其排名值的递增顺序排列。
Step 3 − Drag Rank to the Rows shelf. The following chart appears which shows the dimension Sub-Category with each ship mode arranged in an increasing order of their Rank value.
Step 4 - 使用度量值利润对排名字段应用其他计算。右键单击 Rank（排名）并选择 Edit Table Calculation（编辑表格计算）。根据子类别分区并按运输方式设置，选择按利润字段进行排序。以下屏幕截图显示了应用的计算。
Step 4 − Apply some more calculation to the rank field using the measure Profit. Rightclick on Rank and choose Edit Table calculation. Choose the sorting by the field profit using partition by Sub-Category and addressed by ship mode. The following screenshot shows the calculations applied.
完成上述步骤后，您将获得如下图所示的凸点图。它显示了各个子类别中每个运输方式的利润变化情况。
On completion of the above steps, you will get the bump chart as shown in the following screenshot. It shows the variation of profit for each ship mode across various subcategories.
