---
url: /mosaic/examples/voronoi.md
---
# Voronoi Diagram

The `voronoi` mark shows the regions closest to each point. It is [constructed from its dual](https://observablehq.com/@mbostock/the-delaunays-dual), a Delaunay triangle mesh. Reveal triangulations or convex hulls using the dropdowns.

**Credit**: Adapted from an [Observable Plot example](https://observablehq.com/@observablehq/plot-voronoi-scatterplot).

## Specification

```py \[Python]
import vgplot as vg

penguins = vg.parquet("data/penguins.parquet")

mesh = vg.param(0)
hull = vg.param(0)

view = vg.vconcat(
    vg.plot(
        vg.voronoi(
            penguins,
            x="bill_length",
            y="bill_depth",
            stroke="white",
            stroke_width=1,
            stroke_opacity=0.5,
            fill="species",
            fill_opacity=0.2,
        ),
        vg.hull(
            penguins,
            x="bill_length",
            y="bill_depth",
            stroke="species",
            stroke_opacity=hull,
            stroke_width=1.5,
        ),
        vg.delaunay_mesh(
            penguins,
            x="bill_length",
            y="bill_depth",
            z="species",
            stroke="species",
            stroke_opacity=mesh,
            stroke_width=1,
        ),
        vg.dot(penguins, x="bill_length", y="bill_depth", fill="species", r=2),
        vg.frame(),
        vg.inset(10),
        vg.width(680),
    ),
    vg.hconcat(
        vg.menu(
            label="Delaunay Mesh",
            options=[vg.option("Hide", value=0), vg.option("Show", value=0.5)],
            bind=mesh,
        ),
        vg.hspace(5),
        vg.menu(
            label="Convex Hull",
            options=[vg.option("Hide", value=0), vg.option("Show", value=1)],
            bind=hull,
        ),
    ),
)

```