Dataskera

Polar Bar Chart

The Polar Bar Chart lays bars out around a circle, so a cyclical pattern reads as a shape instead of a row. Hours of the day, months of the year, points of the compass: when the categories come back round, the first and the last sit next to each other, which is where the pattern usually is.

Data Requirements

Your Tableau worksheet should include:

  • 1 Dimension for the Category encoding. One sector per value, for example Hour, Month or Direction.
  • 1 Measure for the Value encoding. Sets the size of each sector.

Add Polar Bar Chart to your worksheet

First, download the manifest file. It tells Tableau where to load the extension from.

Download polarareachart.trex

Direct link: https://dataskera.com/downloads/polarareachart.trex

Then, in Tableau:

  1. On the Marks card, open the Mark type dropdown, and under Viz Extensions choose Add Extension.
  2. In the Add an Extension dialog, choose Access Local Viz Extensions, then open the polarareachart.trex file you just downloaded.
  3. When Tableau asks, allow the extension to access the data in the workbook.
  4. The welcome screen appears. Sign in with your Dataskera account, or on Tableau Desktop choose Use on Desktop without an account. See Signing in & access below.
  5. Build the chart: drag a dimension onto Category and a measure onto Value.
Tableau Server or Cloud:
A site admin must allow the extension by adding its URL to the site's safe list, and the view needs the Download Summary Data permission. Extension URL: https://vizextension.dataskera.com/polarareachart/polarareachart.html

Signing in & access

Polar Bar Chart is free. Whether you need to sign in depends only on what you are doing. Viewing a dashboard never asks for an account, and authoring is free too.

Viewing a dashboard
No account

People who only view a dashboard are never asked to sign in and are never blocked.

Editing on Tableau Desktop
Optional

Sign in, or continue without an account in a single click.

Editing on Server or Cloud
Free account

Sign in with your Dataskera account to author on the web.

No account yet? Create one free in under a minute. No credit card required.

Format panel

Open the Format panel from the extension menu to customize the chart. It is for the dashboard author and is not shown to viewers. It has four tabs:

  • General: whether the value drives the length of the sector or its area, the start angle and sweep direction, the gap between sectors, the inner radius, the rings and their labels, the category labels around the rim, and the value labels inside.
  • Color: a palette, a precise colour per category, and the overall opacity.
  • Legend: show or hide it, its position around the chart, an optional show/hide toggle for viewers, the colour swatch, and the content of each entry.
  • Tooltip: show or hide it, its colours, decimals, and a template you write yourself from the placeholders the chart provides.
Length or area:
Area is the honest default for a Nightingale rose, because the eye reads the surface of a sector rather than its radius. Length is easier to compare precisely, and both are one click apart.
Negative values:
A sector shows magnitude as a distance from the centre, so a negative value cannot be drawn. Negatives are left out of the ring but stay in the legend with their real value, and a notice on the chart reports how many were not drawn.