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Documentation Grafana documentation Panels Field options

Field options

This page explains what field options and field overrides in Grafana are and how to use them. It also includes examples if you need an idea of how this feature might be useful in the real world.

The data model used in Grafana, the data frame, is a columnar-oriented table structure that unifies both time series and table query results. Each column within this structure is called a field. A field can represent a single time series or table column.

Field options and overrides

Field options allow you to change how the data is displayed in your visualizations. Options and overrides that you apply do not change the data, they change how Grafana displays the data.

Field options, both standard and custom, can be found in the Field tab in the panel editor. Changes on this tab apply to all fields (i.e. series/columns). For example, if you change the unit to percentage, then all fields with numeric values are displayed in percentages. Apply a field option.

Field overrides can be added in the Overrides tab in the panel editor. There you can add the same options as you find in the Field tab, but they are only applied to specific fields. Apply an override.

All field options are defined below.

Standard field options

Standard field options are:

• Unit
• Min
• Max
• Decimals
• Display name
• No value
• Thresholds
• Value mappings
• Data links

You can apply standard field options to most of the built-in Grafana panels. Some older panels and community panels that have yet to update to the new panel and data model will be missing either all or some of these field options.

Custom field options

Some visualizations have custom field options. For example the Table visualization has many custom field options. Community panels can add their own custom field options as well, and they might differ across visualizations.

Configure all fields

To change how all fields display data, you change an option in the Field tab. In the Overrides tab you then override that for specific fields.

1. Navigate to the panel you want to edit, click the panel title, and then click Edit.
2. Click the Field tab.
3. Find the option you want to change.
4. Enter options by adding values in the fields. To return options to default values, delete the white text in the fields.
5. When finished, click Save to save all panel edits to the dashboard.

Configure specific fields with overrides

Overrides allow you to change the settings for one or more fields (i.e. series or column). What fields are targeted by the override depends on the matcher. Field options for overrides are exactly the same as the field options available in a particular visualization. The only difference is that you choose which fields to apply them to.

1. Navigate to the panel you want to edit, click the panel title, and then click Edit.
2. Click the Overrides tab.
3. Click Add override.
4. Select a filter option to choose which fields the override applies to.
5. Click Add override property.
6. Select the field option you want to apply.
7. Enter options by adding values in the fields. To return options to default values, delete the white text in the fields.
8. Continue to add overrides to this field by clicking Add override property, or you can click Add override and select a different field to add overrides to.
9. When finished, click Save to save all panel edits to the dashboard.

Select fields

This section explains the different ways you can select which fields an override rule will be applied to.

Fields with name

Allows you to select a field from the list of all available fields. Properties you add to a rule with this selector will only be applied to this single field.

Fields with name matching regex

Allows you to specify a regular expression. Properties you add to a rule with this selector will be applied to all fields where the field name match the regex.

Fields with type

Allows you to select fields by their type (string, numeric, etc). Properties you add to a rule with this selector will be applied to all fields of matching type.

Field options

This section explains all available field options. They are listed in alphabetical order.

Most field options will not affect the visualization until you click outside of the field option box you are editing or press Enter.

Decimals

Number of decimals to render value with. Leave empty for Grafana to use the number of decimals provided by the data source.

To change this setting, type a number in the field and then click outside the field or press Enter.

Data links

Lets you control the URL to which a value or visualization link.

For more information and instructions, refer to Data links.

Display name

Lets you set the display title of all fields. You can use variables in the field title.

When multiple stats, fields, or series are shown, this field controls the title in each stat. You can use expressions like ${__field.name} to use only the series name or the field name in title.

Given a field with a name of Temp, and labels of {“Loc”=“PBI”, “Sensor”=“3”}

If the value is an empty string after rendering the expression for a particular field, then the default display method is used.

Max

Lets you set the maximum value used in percentage threshold calculations. Leave blank for auto calculation based on all series and fields

Min

Lets you set the minimum value used in percentage threshold calculations. Leave blank for auto calculation based on all series and fields

No value

Enter what Grafana should display if the field value is empty or null.

Unit

Lets you choose what unit a field should use. Click in the Unit field, then drill down until you find the unit you want. The unit you select is applied to all fields except time.

Custom units

You can use the unit dropdown to also specify custom units, custom prefix or suffix and date time formats.

To select a custom unit enter the unit and select the last Custom: xxx option in the dropdown.

• If y u want a space -> If you want a space
• suffix:<suffix> for custom unit that should go after value.
• time:<format> For custom date time formats type for example time:YYYY-MM-DD. See formats for the format syntax and options.
• si:<base scale><unit characters> for custom SI units. For example: si: mF. This one is a bit more advanced as you can specify both a unit and the source data scale. So if your source data is represented as milli (thousands of) something prefix the unit with that SI scale character.
• count:<unit> for a custom count unit.
• currency:<unit> for custom a currency unit.

You can also paste a native emoji in the unit picker and pick it as a custom unit:

String unit

Grafana can sometime be too aggressive in parsing strings and displaying them as numbers. To make Grafana show the original string create a field override and add a unit property with the string unit.

Thresholds

Thresholds allow you to change the color of a field based on the value.

For more information and instructions, refer to Thresholds.

Value mapping

Lets you set rules that translate a field value or range of values into explicit text. You can add more than one value mapping.

• Mapping type - Click an option.
  • Value - Enter a value. If the field value is greater than or equal to the value, then the Text is displayed.
  • From and To - Enter a range. If the field value is between or equal to the values in the range, then the Text is displayed.
• Text - Text that is displayed if the conditions are met in a field. This field accepts variables.

Examples

Here are some examples of how you might use this feature.

Field option example

Let’s assume that our result set is a data frame that consists of two fields: time and temperature.

Each field(column) of this structure can have field options applied that alter the way its values are displayed. This means that you can, for example, set the Unit to Temperature > Celsius, resulting in the following table:

While we’re at it, the decimal place doesn’t add anything to this display. You can change the Decimals from auto to zero (0), resulting in the following table:

Field override example

Let’s assume that our result set is a data frame that consists of four fields: time, high temp, low temp, and humidity.

Let’s apply the field options from the field option example to apply the Celsius unit and get rid of the decimal place. This results in the following table:

The temperature fields look good, but the humidity is nonsensical. We can fix this by applying a field option override to the humidity field and change the unit to Misc > percent (0-100). This results in a table that makes a lot more sense: