I received an interesting request from a user that deserves sharing. The user requested a visualization showing the curve of a normal distribution of data points. Now, just to be clear, a visualization that shows the distribution of data points is a histogram, which looks like this:
The histogram might vary a little bit if you change the number of bins being used, but it always has the continuous value along the X-axis and the (Row Count) on the Y-Axis. However, the user didn’t want to see the bars of the histogram, just a curve that represented the histogram, which would look like this:
Normal Distribution Curve
This type of visualization is simple and easy to create in Spotfire using the following steps.
Creating the Visualization
- Add a bar chart
- Configure the X-Axis with the continuous value and the Y-Axis with (Row Count)
- On the X-Axis, click the down arrow on the axis selector and make sure the “Auto-Bin” box is checked.
- If needed, right click on the axis selector and choose “Number of Bins” to set the desired number of bins.
- In the legend, click on the color circle and color the bars the same color as the background (probably white).
- Go to Properties > Lines & Curves > Add > Gaussian Curve fit
BAM! Done! The Gaussian Curve fit is the normal distribution and represents the histogram as a curve. If you combine the curve and the histogram, it looks like this:
In the end, Spotfire had the functionality to quickly and easily meet the user’s needs!