---
title: "How to colour and size points by two fields"
description: "Show two values on one point layer: colour from a text or numeric field and size from a numeric field. Set both drivers on the Style tab. Point layers only."
sidebar:
  label: "Colour and size by two fields"
search:
  keywords: [bivariate, two variables, proportional symbol, bubble map colour]
---

Pick a field in `Colour markers by` and a numeric field in `Size markers by`, and each marker shows two values at once: its colour from one field and its size from the other. The legend shows the colour rows with a size key under them, so viewers can read both.

**[See it on an example map](https://mangomap-staging.com/examples-staging/maps/042tb3tl/world-point-styling-lab)**

Open the World Point Styling Lab. In the legend, turn on the `Two Fields` folder and turn off `Size and Colour`. `Centroids — Continent and Population` colours each country point by continent and sizes it by population. `Centroids — GDP and Population` colours by GDP per person in five classes and sizes by population.

## Before you start

- The layer must be a **point** layer with at least one numeric field. Lines and polygons have no size driver.
- You need edit access to the map.
- Size applies to `Circle` and `Icon` markers. `Heatmap` has no size or colour driver.
- `Colour by zoom` also works with a size field. See [How to change marker colour by zoom level](/docs/styling-layers/colour-markers-by-zoom).

## Open the Style tab

In the layer panel, select your point layer. Click the `Style` tab.

## Pick the colour field

Open `Colour markers by` and pick the field for colour. A text field gives one colour per value. A numeric field adds `Style as`, where you pick classes, a continuous gradient, or categories. The colour controls are the same as on a single-field layer. See [How to style features by category](/docs/styling-layers/style-by-category) and [How to style features by quantity](/docs/styling-layers/style-by-quantity).

## Pick the size field

Open `Size markers by` and pick the numeric field for size. The single size slider is replaced by a `Minimum size` and `Maximum size` range in pixels. The smallest value in the field draws at the minimum size and the largest at the maximum.

<img src="/_assets/styling-layers/colour-and-size-points-by-two-fields--style.png" alt="Style section of the Centroids — Continent and Population layer with Marker type Circle, Colour markers by set to continent with a Colour palette and eight category rows, and Size markers by set to pop_est with Minimum size 4 px and Maximum size 24 px" width="1600" height="960" />

Widen the range when the colours hide the size differences. A range of 4 to 24 px reads well on a world map; a city map can take a smaller range.

## (Optional) Scale the sizes as viewers zoom

On `Circle` markers, click `Vary size by zoom level` next to the size range. Each stop then holds a `Scale` that multiplies both sizes at that zoom. See [How to vary marker size by zoom level](/docs/styling-layers/vary-marker-size-by-zoom).

## Save

Click `Save` at the bottom of the panel. The map redraws with both fields applied.

## What viewers see in the legend

The legend shows the colour rows first, then a size key of three circles for the size field. The size key's caption is the size field's alias from the `Format` tab, or the field name when it has no alias.

<img src="/_assets/styling-layers/colour-and-size-points-by-two-fields--legend.png" alt="World Point Styling Lab as a viewer sees it with Centroids — Continent and Population on: country points in a colour per continent and sized by population, and the legend entry showing the eight continent swatches with a size key of three circles below them" width="1600" height="960" />

## If the two fields fight each other

Two drivers on one layer is a lot to read. When the map gets busy, try one of these:

- Use a light palette for the colour field, so the size differences stay visible.
- Give the circles a thin white outline, so overlapping markers keep their edges.
- Raise the minimum size. Tiny markers lose their colour.
- Split the layer in two and let viewers switch between them in the legend.

## If you want size steps instead of a smooth range

The size driver maps values to a smooth range. For a fixed size per category or class break, leave `Size markers by` on `Uniform size` and set a size on each row instead. See [How to customise category and class break symbology](/docs/styling-layers/customise-category-and-class-break-symbology).

## Related

- [How to size points by a number](/docs/styling-layers/size-points-by-a-number)
- [How to style features by category](/docs/styling-layers/style-by-category)
- [How to style features by quantity](/docs/styling-layers/style-by-quantity)
- [How to vary marker size by zoom level](/docs/styling-layers/vary-marker-size-by-zoom)
- [Point layer style controls](/docs/styling-layers/point-style-reference)
- [Planning a thematic map in MangoMap](/docs/styling-layers/concepts-planning-a-thematic-map)