Select a one- or two-dimensional region using the mouse or touch.

Kerry Rodden

Brushable parallel coordinates

Quadtree brush

Mike Bostock

Focus + Context

brush.filter

Mona Lisa Histogram

Click to Recenter Brush

Brush Snapping (Transitions)

Ordinal Brushing

Empty Brush Selection

Brush Handles

Brush Snapping

Double-Click to Brush

Brushable scatterplot matrix

Brush transitions

Brushable scatterplot

D3 Documentation

d3-brush

Explore and explain patterns in quantitative data using D3, Vega, and Observable Plot

Observable

Visualization

Gallery

```
const svg = d3.create("svg")
      .attr("viewBox", [0, 0, width, height])
      .property("value", []);
```

this part set the svg element, but I don't know why have to set the property of `value` to an empty array?

Benbinbin

The svg element's value property informs the contents of the selection variable, which will then be updated when we brush (with the call to "dispatch"). Since we want to begin with an empty selection, we have to set it explicitly to [] (rather than undefined).

cars-2.csv