# Gauge Chart Applications

Tableau Gauge Charts are effective in displaying the change of a linear progressive value, or the change of different entities over a common parameter. Gauge Charts are widely used in Tableau in various industries and businesses to measure Key Performance Indicators (KPIs). Gauge Charts look like half of a Doughnut Chart, with a Needle indicating the value. A Doughnut Chart is simply a Pie Chart with a hole in the middle.

## Create a Gauge Chart in Tableau

Creating a Tableau Gauge Chart will need a few slices of Doughnut and a Needle with a Percentage value. We are using 5 slices to achieve our goal. Slice F1 starts at 270° and ends between 270-360°, slice F2 starts and ends between 270° and 360°, slice F3 starts at 0° and ends between 0-90°, slice F4 starts and ends between 0° and 90° after F3, slice F5 starts at 90° and ends at 270°.
× Gauge Charts are helpful in indicating the progress and values of metrics, but can get complex if we add many categories to it. Example Good, Average, Poor is fine, but more values can lead to difficulty for the end-user.

## Tableau Gauge Chart Calculation Steps

A few simple mathematical calculations are needed to define our slices F1, F2, F3, F4, F5, Indicator1, Indicator2 as seen above. We create a metric called % of Total to understand which Rock Type were associated the most with the total number of Volcanoes. FX is a placeholder dimension member which helps adjust the Colors of the Inner Pie. We color the Indicators forming the Needle black, and the remaining members white for the Inner Pie.

## Tableau Gauge Chart Dynamic Labels

Once the Gauge Chart is created in Tableau, it is time to add Labels as per the best practices. We create additional worksheets to achieve this as shown above. In the new sheet, drag the field which we want to use as label onto the Text Marks card. In this case, we put the % of Total Volcanoes value. Then, we create a Parameter on Dominant Rock Type so that we can choose the Rock Type value. We create a Rock Type Filter that compares the input parameter value with the Dominant Rock Type and returns True if it matches, else False. Simply drag this filter in the Filters shelf and filter by True in both the Chart sheet and the % of Total value sheet. Thus by a single parameter selection both the sheets will get updated when we arrange them nicely in a Dashboard.

## When to use Tableau Gauge Charts

The Tableau Gauge Charts can be powerful tools to investigate performances of individual KPIs or metrics. The robust view of a Gauge Chart that instantly delivers the message on how a value is performing and how much remaining to achieve completion offers plentiful use-case for all business leaderships. Often a dashboard is seen to contain several Gauge Charts side by side in rows and columns offering a distinct view for each metric measured. The reason is simple, our eyes are trained at discerning bars better than arcs. So instead of adding multiple arcs in the same Gauge Chart, it is better to split them into individual charts. Thus Gauge Charts are used when a distinct clear snapshot about the progress of a metric has to be analyzed in an aesthetic way.

## Tableau Gauge Chart is a Combination Chart

Did you notice how close a Gauge Chart looks like a Pie Chart sometimes, yet it is not exactly a Pie Chart. A Gauge Chart looks so similar to a Doughnut Chart, yet it is not exactly a Doughnut Chart. This is because it is a Combination Chart, along with few modifications to convert it into a semicircle along with appropriate shadings. That is the reason many of the steps that are performed while creating a Gauge Chart in Tableau is similar to the steps performed while creating a Pie Chart, and the steps performed while creating a Doughnut Chart.