Working with gauges
- Elements of a gauge
- Types of gauges
- Adding a gauge
- See also
A gauge is typically used to visualize metrics having a single value, such as the total revenue for the year-to-date. In other words, a gauge displays one or more measures from a single row, and is not designed to display multiple rows of data.
Available gauge types include linear and radial (or circular) gauges.
2. Elements of a gauge
The figure below shows the main elements of a gauge visualization.
3. Types of gauges
3.1. Linear Gauge
A linear gauge is characterized by a linear scale which can be horizontal or vertical in orientation.
3.2. Bullet Graph
A bullet graph is a variation of a linear gauge that displays an actual value and a target value. It may also show ranges that identify if a value is within a defined state. Bullet graphs convey meaningful information in a compact space, making them ideal for dashboards that need to display a number of single-valued metrics, such as the current year-to-date sales revenue.
3.3. Radial Gauge
A radial gauge has a pivot point around which its pointers rotate, plus a radial scale. By default, the radial scale forms a complete 360-degree circle but you can easily change it to display as an arc by adjusting its start and sweep angles.
3.4. Pie Gauge
A pie gauge is a variation on a radial gauge that displays a metric as a percentage of the length of a circular scale, like a pie or donut chart with a single slice.
4. Adding a gauge
The following is a brief walkthrough that shows you how to add a gauge to your dashboard.
First, create a new dashboard from the main menu and use the Blank template.
Go to the toolbar, click Data Visualization, scroll to the right, and click Radial Gauge.
This adds an empty radial gauge to the canvas with its Data Analysis Panel open.
Go to the Explore window and locate a measure column you want to visualize. Drag the measure onto the empty gauge.
A basic radial gauge is displayed which includes a pointer (of type needle), a scale with labels, and major tick marks.
Right click on the radial gauge, click Re-visualize, and then select Linear Gauge.
This turns it into a linear gauge. Depending on its dimensions, the scale of the linear gauge will be oriented horizontally or vertically. This is because the gauge scale's Orientation property is set to Auto by default.
You can access the properties of a gauge scale from the Main tab in the Properties window.
5.1. Start and Sweep Angle
By default, the scale of a radial gauge forms a nearly 360-degree circle. You can change the start and sweep angles of the gauge's scale to have the gauge display as an arc (i.e., a partial circle).
The gauge's Start Angle property specifies the angle at which to start drawing the scale. This is an angle in degrees between 0 and 360, which is measured clockwise from the 6 o'clock position. For example, to produce the semi-circular radial gauge shown at the beginning of this article, set the start angle to 90 degrees.
The Sweep Angle property is an angle representing the length of the arc and is measured in degrees. For example, to produce the semi-circular radial gauge shown at the beginning of this article, set the sweep angle to 180 degrees.
5.2. Minimum and Maximum
The scale's minimum and maximum values are determined automatically based on the gauge's underlying data. However, you can override this by setting the gauge scale's Minimum and/or Maximum properties manually.
If the Minimum and Maximum properties are not set on a gauge scale, and the Round Minimum & Maximum property is turned on, then rounded values for the scale minimum and maximum will be calculated automatically.
For pie gauges, which do not display any scale labels, the Round Minimum & Maximum property is turned off by default because rounding can be misleading. Instead of using rounding, you can do one of the following for a pie gauge:
- Set up states which are displayed as ranges on the gauge
- Add a second measure which will be displayed as a second pointer (e.g., a target)
- Set the Maximum property manually
As shown in the walkthrough, use the gauge scale's Orientation property to orient a linear gauge horizontally or vertically. By default, this property is set to Auto, which means the orientation is adjusted automatically based on the width and height of the gauge.
5.5. Interval and Interval Count
The Interval and Interval Count properties can be set on a scale itself, or on its major tick marks, minor tick marks, or labels.
By default, the Interval Count on the scale is set to 5 which means the scale is divided into 5 sections.
The Interval property lets you override the interval count by specifying the size of each interval based on measure units. For example, in the figure below, the interval is set to 20,000 and the total number of intervals is determined automatically based on that value.
5.6. Label Style
To customize gauge labels, go to the Properties window for the scale series, click the Text tab.
For example, go to the Text tab to change how you want large numeric values to be formatted. (But note that the defaults are already set up to generate compact labels and avoid overlap when displaying large values.)
By default, the scale of a radial gauge is centered within its rectangular bounds. You can change this by going to the Layout properties for the gauge (not the scale). Then use the Horizontal Alignment and Vertical Alignment properties to align the scale as needed.
A gauge has one or more pointers which correspond to the measures from a metric set. A second pointer is often used in gauges to represent a target measure or contextual metric value. Each pointer can be independently customized in terms of appearance and layout.
6.1. Pointer Type
The Pointer Type property has 3 options: Bar, Marker, and Needle. A radial gauge can use any of these pointer types but a linear gauge only supports Bar and Marker.
Note that a bar pointer is not displayed when the value is zero.
6.2. Marker Shape
If your pointer type is Marker, use the Marker Shape property to choose between a number of available shapes.
Go to the Layout section of a pointer's properties to find the Placement property. Use this property to control whether the pointer (e.g., marker) should be placed on the inside or outside of the scale, or placed in the center of the scale.
Gauge ranges correspond exactly to states belonging to a metric set state group. Showing ranges on a gauge helps users to quickly identify the condition of the measure being monitored.
7.1. Set up states
To set up ranges for a basic gauge, first select the gauge on the canvas, go to the toolbar, click Data Tools, and then click Set Up States.
In the Set Up States dialog, add a new state group and name it State Group 1. Then add a Good state and a Bad state using a Constant (Formula) value of 150000 as the threshold.
7.2. Range State Group
Next, go to the properties for the gauge. On the Main tab, set the Range State Group property to State Group 1 which is the state group that was just created.
Ranges are automatically added to the gauge with default colors.
7.3. Start and End Width
In the Properties for the gauge, on the Main tab, you'll see a list of ranges corresponding to the states (e.g., Good and Bad). Click on a range to edit its appearance.
For example, change the fill color, Start Width, and End Width of the two ranges to achieve the look shown in the figure below.