In last week’s post, we learned about the different ways to draw Lines in a Visualization using data from different data tables. In this week’s post, we will learn how to properly use the different mechanisms for drawing curves in TIBCO Spotfire.
Let's assume that we have the same original data table that we discussed last week:
What if we want to show a curve in our visualization based off some expression? Suppose we want to show the recommended cholesterol limits for our population by age, or we want to show a formula predicting cholesterol. For example, if we had a general formula where Cholesterol (C) can be predicted based upon Age (A):
C = 150 + 1.5*A
We can use the Curve Draw feature of Spotfire to input this expression and calculate the Y values to draw the curve on our visualization.
Step 1: Launch the Line From Data Table dialog from the Lines & Curves Properties dialog
Step 2: Specify the expression to use
Step 3: The line is drawn.
If we want to use values from our data table, or another data table, in our expression, we can't use the Curve Draw feature. Howvever, we can use the Curve from Data Table feature. For example, we can use values from the Limits data table (which we learned about in last week’s tip), as part of an expression. In this example, cholesterol limits (Cl) are adjusted with Age (A) according to the following expression:
newCl = (Cl - 30) + 0.67*A where Cholesterol limit is a column from our limit's Data table
Step 1: Launch the Curve From Data Table dialog from the Lines & Curves Properties dialog
Step 2: Specify the expression to use, including any columns from the Data table.
Step 3:The lines are drawn (one for the lower limit and one for the upper limit since there are two unique values in the Cholesterol Limit column)
To summarize, Curve from Data Table is similar to Line from Data Table, except you can use data columns from another Data table as part of an expression to determine the Y values for each line. Curve Draw also gives you the ability to create an expression; however, you cannot include data columns as a part of that expression.For more information on Lines and Curves and other statistics, please consider taking our Spotfire Essentials courses. If you are interested in doing more detailed, multivariate data analysis, please consider taking our new course: Multivariate Data Analysis in TIBCO Spotfire.
