Orbit Charts in Tableau : An unusual yet insightful visualization

An Orbit chart (also known as a satellite chart ) in Tableau, is a way to visualize data where each orbit or radial axis represents a specific value or category. It is often used to show the progress of a metric or to compare different datasets.

Key Features of Orbit Charts

-          A more comprehensive view, offering a cleaner and more concise way to display related data.

-          Easier to compare and analyze data, as they provide a visual representation of the relationships between different values.

-          Can be customized with different colors, shapes, and labels to further enhance their visual appeal and make them easier to interpret. 

About the Data

The data we’ll be analyzing here, contains the clinical findings of early prediction of Sepsis Patients.

Sepsis is a life-threatening condition that occurs when the body's response to infection causes tissue damage, organ failure, or even death. Early detection and antibiotic treatment of sepsis are critical for improving sepsis outcomes. Late prediction of sepsis is potentially life-threatening and predicting sepsis in non-sepsis patients or predicting sepsis very early in sepsis patients, consumes limited hospital resources.

This Dataset contains 40,336 total Patients, out of which 37,404 patients do not have Sepsis on hospital admission.  2,506 are onset Sepsis Patients i.e. these patients did not have sepsis when admitted to hospital but converted to sepsis after admission. Only 426 patients were found to have sepsis on hospital admission.

Lets start building the chart

First step is to load the data into Tableau Desktop / Public.

Establishing Data Connection

1.      Connect the dataset ’Dataset1.csv’ to the data source.

2.      Create a path file in excel with values 0 and 360

3.   Add the excel file ‘path’ using ‘Add’ tab. This will show the path file in connections as well as in sheets.

4.Open the table ‘Dataset.csv’ using right click and drag the path file from sheets to the dataset table. This will further open the type of join that needs to be made between the two tables.

Now we have to join both the tables i.e. Dataset and path. This will create two records for each existing record. So lets create the join calculation between two tables.

5.  Go to 'Create join calculation' in Data source. This will open a calculated field window. Enter ‘1’ and click ‘ok’ . And in similar way move next to the path table and create the same calculation.

The connection has been established and now we are ready to start creating our visualization.

6.Next, create Calculated Fields & Bins

To create Path(Bin):

Go to 'Path' > Create >Bins>Change the Size of bin to 1 >click ‘ok’

7.Create a calculated field for index calculation. This will represent the angle in degrees.

Index

INDEX()-1

Create "X" Coordinate and "Y" Coordinate fields based on the Index using sine and cosine.

X Coordinate

Create a calculated field called "X" using the formula

COS(RADIANS([index]))

Y Coordinate

Create a calculated field called "Y" using the formula

SIN(RADIANS([index]))

8.Now drag the calculated field ‘Sepsis Category’’ to column shelf

‘Y’ to column shelf

‘X’ to Rows

Path(bin) to Details

9. Then go to ‘X’ in rows shelf and click on drop down. Select ‘Compute Using’ and then select Path(Bin). Follow the same steps for ‘Y’ in column shelf.

Now the circle will appear for each category.

10.Drag ‘Sepsis Category’ to Color and In Marks Card, change from ‘Automatic’ to ‘Line’.

11.Drag the Path(bin) to ‘Path’. This will create the outline of the circles.

12. Create new calculated fields for

‘Patients’  

WINDOW_SUM(COUNTD([Patient ID]))/2

‘Total Patients’

WINDOW_SUM(COUNTD([Patient ID]))/2

‘Percentage’

[Patients]/[Total Patients]

‘Size’  (To define the size )

IF [index]/WINDOW_MAX([index]) < [Percentage]

THEN 1

ELSE 0

END

13.Bring the ‘Size’ field to size in ‘Marks’ Card.

14.Now  Go to 'Size' in  Marks Card and select ‘Compute Using’ and select ‘Path(Bin)’

15.Now again go to ‘Size’ and this time select ‘Edit Table Calculation’ and change ‘Nested Calculation’ to ‘Total Patients’ from drop down menu and check the box ‘Sepsis Category’ at the bottom.

Our chart is almost ready. Now comes the formatting part.

16.Create another calculated field ‘Zero’ with value ‘0’ in it.

17.Drag the ‘Zero’ field to Rows and create Dual Axis from the drop down and then ‘Synchronize the Axis’. Remove headers  from both ‘X’ and ‘Y’ axis.

18. Go to Format Borders >Borders> Sheet > Row Divider Pane & column Divider Pane to ‘none’

Go to Lines > Sheet > change all Types of Lines to ‘none’

19.In ‘Marks’ Card, select the ‘Sum(Zero)’ and change the ‘Line’ to ‘Text’. Remove ‘Path’ and ‘Measure Names’.

20.Drag Patients field to ‘Text’. This will show the No. of Patients in each category.

 Define the Page Title and change the color of the rings If you want.

The visualization is complete now.

When to use Orbit Charts

·       Progress Tracking

·       Comparing Data

·       Visualizing Hierarchical Data

·       Alternative to Pie or Doughnut Charts(to represent the same data in a less cluttered way)

In summary, Orbit charts are a valuable tool for visualizing a single value, progress towards a goal, or as a modern alternative to pie charts when the focus is on highlighting a specific percentage or value.