# Sankey

> A dashboard item that draws flows between nodes as bands whose width follows the amount, such as energy from its sources to plants and areas.

Source: https://proxus.io/docs/analyze/dashboard-items/sankey

The **Sankey**  draws how an amount flows from one place to the next.
Each band runs from a source to a target and is as wide as the amount it carries. Use it to show where energy, water,
material or product goes and where it is lost: an energy dashboard, a material balance, a yield review.

*Screenshot: The Sankey on the Meridian energy dashboard: electricity from grid import, solar PV and CHP flowing into each plant, and from each plant on to its metered areas and its building and HVAC load*

1. **Node.** One value of **Source** or **Target**, such as a supply or a plant. Its height is the total that flows
   through it, and each node has its own colour.
2. **Link.** One flow from a source to a target, as wide as its **Value**. It shades from the source's colour to the
   target's.
3. **Label.** The node's name, to the right of the node. Long names are shortened to fit.

Hover a node to highlight its links, or a link to see its source, target and amount. Select a link to filter the other
items of the dashboard by it, or to drill down if the item has a drill-down set up.

## Data fields

All three fields are required; without them the item stays empty. Each row is one link. A node that is the target of
one row and the source of another becomes a middle column, so a single query can describe several steps. **Value**
must be a number; rows with an empty or non-numeric value are left out. Amounts in the tooltip are rounded to whole
numbers.

## Settings

- **Node width** is the width of each node in pixels.
- **Node gap** is the space between nodes in the same column, in pixels.
- **Link opacity** sets how solid the links are, from 0.1 to 1. Lower values let crossing links show through.

## Where to see it

The Meridian demo plant uses it on **Meridian · Energy & Sustainability**, in the item "Where electricity comes from
and goes". It shows the electricity over the dashboard's period in kWh: grid import, solar PV and CHP into each plant,
and each plant on to its sub-metered areas and the rest of its load (building and HVAC).

## Related

- [Proxus dashboard items](https://proxus.io/docs/analyze/dashboard-items)
- [Use and build dashboards](https://proxus.io/docs/analyze/dashboards)