Special Values

Some data requires special handling in Tableau. Specifically null values, unrecognized or ambiguous geographic locations, negative or zero values when working with a logarithmic scale, and negative or zero values when working with treemaps. When your data contains these special values, Tableau cannot plot them in the view. Instead, an indicator displays in the lower right corner of the view. Click the indicator to see more options for how to handle these values.

Null Numbers and Dates and Negative Values on Log Axes

When you drag a measure or continuous date to the view, the values are shown along a continuous axis. If the field contains null values or there are zero or negative values on a logarithmic axis, Tableau cannot plot them. Instead, these values are shown using an indicator in the lower right corner of the view. Click the indicator and choose from the following options:

• Filter Data - exclude the null values from the view using a filter. When you filter data, the null values are also excluded from any calculations used in the view.
  
• Show Data at Default Position - show the data at a default location on the axis. The null values will still be included in calculations. The default position depends on the data type. The table below defines the defaults.
  

  Type of Data	Default Position
  Numbers	0
  Dates	12/31/1899
  Negative Values on a Log Axis	1
  Unknown Geographic Location	(0,0)

Unknown Geographic Locations

When working with maps and geographic fields, any unknown or ambiguous locations display in the indicator in the lower right corner of the view. Click the indicator and choose from the following options:

• Edit Locations - correct the locations by mapping your data to known locations.
  
• Filter Data - exclude the unknown locations from the view using a filter. The locations will not be included in calculations.
  
• Show Data at Default Position - show the values at the default position of (0, 0) on the map.
  

Zero and Negative Values in Treemaps

When working with treemaps, any null or zero values display in the indicator in the lower right corner of the view. Click the indicator and choose from the following options:

• Filter Data - exclude the unknown locations from the view using a filter. The locations will not be included in calculations.
  
• Use Absolute Values - use the absolute value to determine the size of the corresponding area in the view. For example, both values of 5 and -5 are shown as the same size.
  

If you don’t know how to handle the values, you can choose to leave the special values indicator. Generally, you should continue to show the indicator so that you know there is data that is not being shown in the view. However, to optionally hide the indicator, right-click it and select Hide Indicator.