---
title: "Sankey Diagram in Preset"
slug: "sankey-diagram"
description: "Description and usage of the Sankey Diagram chart in Preset Cloud."
updated: 2023-10-13T18:51:46Z
published: 2023-10-13T18:51:46Z
canonical: "docs.preset.io/sankey-diagram"
excludeFromSearch: true
excludeFromExternalSearch: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.preset.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Sankey Diagram

## Overview

A Sankey diagram is a popular flow diagram that conveys the relative size of metric data based on the size of flow lines from a source to a target. Here is an example:

![](https://cdn.document360.io/4749ddf8-aa05-4f3f-80e1-07a5d2d0f137/Images/Documentation/Screen%20Shot%202022-09-20%20at%206.50.14%20PM.png)

### Reference Content

The following articles may be useful resources as you build your chart:

- [Creating a Chart](/v1/docs/creating-a-chart): A walkthrough of the overall process of chart selection and creation.
- [Using Preset Chart Builder](/v1/docs/using-preset-explore): How to work with the Chart Builder page, the primary interface used when creating a chart.

## Creating a Sankey Diagram

Similar to a [tree chart](/v1/docs/tree-chart), a Sankey diagram uses nodes (represented visually as rectangles), edges (represented visually as flows), and hierarchy (left to right). Unlike a tree chart, the emphasis is on the flow between nodes instead of the hierarchy itself. The hierarchy represents stages in a system flow.

**Shape of your Data**

Structuring your data in the right shape is crucial for building effective Sankey diagrams. Let's zoom into a specific example of how a row in the dataset maps to a node-edge-node pair in the diagram.

| ![](https://cdn.document360.io/4749ddf8-aa05-4f3f-80e1-07a5d2d0f137/Images/Documentation/Group%2027.png) | - The **source** column specifies the originating node in the chart. - The **target** column specifies the receiving (or destination) node in the chart. - The **count** value is used to scale the thickness of the connecting flow rectangle. This value is also shown when a user hovers over the connecting flow rectangle. |
| --- | --- |

To scale this approach up and build a full Sankey diagram, Preset uses your data to calculate all of the **source-target** pairs and then orders them from left to right when generating the visualization. Which nodes go in the left-most column (or first layer of nodes) then? The unique values in the **source** column that ***aren't in the target column (or receive flow)*** end up in the first layer.

Here's the full example:

![](https://cdn.document360.io/4749ddf8-aa05-4f3f-80e1-07a5d2d0f137/Images/Documentation/Screen%20Shot%202022-09-20%20at%2010.59.05%20PM.png)

Now we'll walkthrough the options we selected in Chart Builder and how the data was transformed:

| ![](https://cdn.document360.io/4749ddf8-aa05-4f3f-80e1-07a5d2d0f137/Images/Documentation/Screen%20Shot%202022-09-20%20at%207.50.35%20PM.png) | **Underlying Data** - Our data in this example is pre-aggregated in the *count* column. - The *source* and *target* columns map to the nodes we want visualized. |
| --- | --- |
| ![](https://cdn.document360.io/4749ddf8-aa05-4f3f-80e1-07a5d2d0f137/Images/Documentation/Screen%20Shot%202022-09-20%20at%2010.54.44%20PM.png) | **Chart Builder Options** - **Source / Target**: specify the column you want for the source nodes first and the column you want for the target nodes second. - **Metric**: specify the aggregate and column you want used for the thickness of the flow between the nodes |

Here's the query that was generated:

```plsql
SELECT source AS source,
                 target AS target,
                 sum(count) AS "SUM(count)"
FROM main."Example: Sankey"
GROUP BY source,
         target
```