# Choosing a chart (/docs/charts)

> Six peer chart modules, each answering one kind of question and owning its own transition rules.

Each chart module is an independent peer. Its builder adds chart-specific
methods to the [shared grammar](/docs/concepts/chart-states#shared-grammar), and
the module decides how its marks move. Both endpoints of a transition must use
the same chart type.

| Chart                         | Question it answers                          | Chart-owned rule                                         |
| ----------------------------- | -------------------------------------------- | -------------------------------------------------------- |
| [Bar](/docs/charts/bar)       | How do categories compare?                   | Bars share a quantitative baseline                       |
| [Line](/docs/charts/line)     | How does a value change in order?            | Keys identify points inside paths; gaps stay honest       |
| [Area](/docs/charts/area)     | How does magnitude or composition change?    | Explicit baseline and stacked boundaries                 |
| [Point](/docs/charts/point)   | How do two quantities relate?                | Compact Cartesian axes; entering points grow in place    |
| [Unit](/docs/charts/unit)     | How many countable items are there?          | Grid, force, unit-bar and beeswarm layouts; shortest travel |
| [Pie](/docs/charts/pie)       | What share of one total does each part take? | Keyed angular motion; direct transitions only            |

Every chart can also be partitioned into [small multiples](/docs/charts/repeat)
with `.repeat()`.

## Import only what you use [#import-only-what-you-use]

```ts
import { line } from 'visdelta/line';

const chart = line(rows)
  .x('date', { type: 'temporal' })
  .y('close');
```

A builder carries its chart module, so `transition()` loads only the renderer
it needs.

## Design warnings [#design-warnings]

Each chart module can also report advisory design warnings, such as too many
stacked columns or a truncated bar baseline. They never change what renders.
See [Visualization warnings](/docs/guides/warnings).