mbostock

Color spaces! RGB, HSL, Cubehelix, Lab and HCL (Lch).

Convenient parsing for Fetch.

Manipulate TopoJSON and convert it to GeoJSON.

Handy data structures for elements keyed by string.

A readable stream reader that reads a desired number of bytes.

Visualize flow between nodes in a directed acyclic network.

Convert GeoJSON to TopoJSON for smaller files and the power of topology!

Group two-dimensional points into hexagonal bins.

Data-driven DOM manipulation: select elements and join them to data.

Array manipulation, ordering, searching, summarizing, etc.

An efficient queue capable of managing thousands of concurrent animations.

Data-Driven Documents

Read arrays as standard WhatWG streams.

Lightweight user interface components

The **Observable Runtime** implements reactivity in both [Observable Framework](https://observablehq.com/framework/) and [Observable notebooks](https://observablehq.com/documentation/notebooks/).

Hypertext Literal

Pre-built TopoJSON from Natural Earth.

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

Drag and drop SVG, HTML or Canvas using mouse or touch input.

Interpolate numbers, colors, strings, arrays, objects, whatever!

Layout algorithms for visualizing hierarchical data.

Encodings that map abstract data to visual representation.

Graphical primitives for visualization, such as lines and areas.

Pan and zoom SVG, HTML or Canvas using mouse or touch input.

Animated transitions for D3 selections.

Force-directed graph layout using velocity Verlet integration.

Easing functions for smooth animation.

Register named callbacks and call them with arguments.

A convenient alternative to XMLHttpRequest.

Generate random numbers from various distributions.

Displays automatic reference lines for scales.

Two-dimensional recursive spatial subdivision.

Visualize relationships or network flow with an aesthetically-pleasing circular layout.

Topology-preserving simplification and filtering for TopoJSON.

Serialize Canvas path commands to SVG.

Compute the quadtree tiles to display in a rectangular viewport.

A parser and formatter for delimiter-separated values, such as CSV and TSV

Compute the Voronoi diagram of a set of two-dimensional points.

Compute the Voronoi diagram of a set of two-dimensional points.

Operations for two-dimensional polygons.