One of the first things I learnt when exploring Tableau is that blue indicates a dimension whilst green indicates a measure. It’s Tableau 101. Except it isn’t.
Blue actually represents discrete fields, whilst green represents continuous fields.
Discrete fields:
- Finite values in a data field.
- For example, the field ‘fruit’ may contain apple, orange and banana only.
Continuous fields:
- Infinite values in a data field.
- For example, the field ‘temperature’ contains values in an infinite range.
Another way to understand the distinction between discrete and continuous is that discrete fields produce headers whilst continuous fields produce axes.
So what about dimensions and measures?
Dimensions:
- Categorical data, which is why they are often blue,
Measures:
- Quantitative data that can be aggregated, therefore often green.
What does it mean when dimensions are green and measures are blue?
When dimensions are green they are continuous dimensions. Continuous dimensions are categories that form an uninterrupted sequence. For example, dates written; “January, 1, 2025”, “January, 2, 2025”, “January, 3, 2025”.
When measures are blue they are discrete measures. Discrete measures are countable but distinct values. For example, the quantity of products sold in whole numbers.
Last thing to remember is that Blue comes before Green!!!