D3 data formats

Data Formats - CSV

The following entries describe the content of the heading row
and the first data row in each CSV file.


axis            "../data/stocks.csv"

  symbol                S&P 500
  date                  Jan 2000
  price                 1394.46


bar             "sample-data.csv"

  name                  AL
  value                 4708708


calendar        "dji.csv", "vix.csv"

  Date                  2010-10-01
  Open                  10789.72
  High                  10907.41
  Low                   10759.14
  Close                 10829.68
  Volume                4298910000
  Adj Close             10829.68


crimea          "crimea.csv"

  date                  5/1854
  wounds                0
  other                 95
  disease               105


parallel        "cars.csv"

  name                  AMC Ambassador Brougham
  economy (mpg)         13
  cylinders             8
  displacement (cc)     360
  power (hp)            175
  weight (lb)           3821
  0-60 mph (s)          11
  year                  73


population      "population.csv"

  year                  1850
  age                   0
  sex                   1
  people                1483789

showreel        "../data/stocks.csv" (see axis)


zoom            "sp500.csv"

  date                  Jan 2000
  price                 1394.46

Data Formats - JSON

The following entries describe the content of the JSON object,
including some example data.

albers          "../data/us-states.json"

  {
  |   "type":       "FeatureCollection",
  |   "features":   [
  |   |   {
  |   |   |   "type":       "Feature",
  |   |   |   "id":         "01",
  |   |   |   "properties":   {
  |   |   |   |   "name":         "Alabama"
  |   |   |   },
  |   |   |   "geometry":     {
  |   |   |   |   "type":         "Polygon",
  |   |   |   |   "coordinates":  [ [ [ -87.35, 35.00 ], ... ] ] ]
  |   |   |   }
  |   |   }
  |   ]
  }


azimuthal       "../data/world-countries.json" (ala albers)


bar             "../data/flare.json"

  This data structure is very complicated; see the file for more details.

  {
  |   "name":       "flare",
  |   "children":   [
  |   |   {
  |   |   |   "name":       "analytics",
  |   |   |   "children":   [
  |   |   |   |   {
  |   |   |   |   |   "name":       "cluster",
  |   |   |   |   |   "children":   [
  |   |   |   |   |   |   {
  |   |   |   |   |   |   |   "name":   "AgglomerativeCluster",
  |   |   |   |   |   |   |   "size":   3938
  |   |   |   |   |   |   }
  |   |   |   |   |   ]
  |   |   |   |   }, ...
  |   |   |   ]
  |   |   }, ...
  |   ]
  }


bonne           "../data/world-countries.json" (ala albers)


bubble          "../data/flare.json" (see bar)


bullet          "bullets.json"

  [
  |   {
  |   |   "title":      "Revenue",
  |   |   "subtitle":   "US$, in thousands",
  |   |   "ranges":     [ 150, 225, 300 ],
  |   |   "measures":   [ 220, 270 ],
  |   |   "markers":    [ 250 ]
  |   }, ...
  ]


bundle          "../data/flare-imports.json"

  [
  |   {
  |   |   "name":     "flare.analytics.cluster.AgglomerativeCluster",
  |   |   "size":     3938,
  |   |   "imports":  [ "flare.animate.Transitioner", ... ]
  |   }, ...
  ]

cartogram       "../data/us-states.json" (see albers)


chord           "../data/flare-imports.json" (see bundle)


choropleth      "unemployment.json"

  {
  |   "01001":    9.7, ...
  }


cluster         "../data/flare.json" (see bar)


force           "miserables.json"

  {
  |   "nodes":  [
  |   |   {
  |   |   |   "name":     "Myriel",
  |   |   |   "group":    1
  |   |   }, ...
  |   "links":  [
  |   |   {
  |   |   |   "source":   1,
  |   |   |   "target":   0,
  |   |   |   "value":    1
  |   |   }, ...
  |   ]
  }

great-arc       "../data/us-states.json"          (see albers),
                "../data/us-state-centroids.json" (ala albers)


horizon         "unemployment.json" (N.B., differs from choropleth)

  {
  |   "year":     [ 2000, ... ],
  |   "month":    [ 1,    ... ],
  |   "rate":     [ 4.5,  ... ]
  }


kde             "../data/faithful.json"

  [ 79, ... ]


marimekko       "../data/marimekko.json"

  [
  |   {
  |   |   "market":   "Auburn, AL",
  |   |   "segment":  "Almond lovers",
  |   |   "value":    3840
  |   }, ...
  ]


mercator        "../data/world-countries.json" (ala albers)


node-canvas     "../data/us-counties.json" (ala albers)


pack            "../data/flare.json" (see bar)


partition       "../data/flare.json" (see bar)


qq              "turkers.json"

  [ 0.01, ... ]

splom           "flowers.json"

  {
  |   "traits":   [ "sepalLength", "sepalWidth",
  |                 "petalLength", "petalWidth" ],
  |   "species":  [ "setosa", ... ],
  |   "values":   [
  |   |   {
  |   |   |   "sepalLength":    5.1,
  |   |   |   "sepalWidth":     3.5,
  |   |   |   "petalLength":    1.4,
  |   |   |   "petalWidth":     0.2,
  |   |   |   "species":        "setosa"
  |   |   }, ...
  |   ]
  }


symbol-map      "../data/us-states.json" (see albers)


tree            "../data/flare.json" (see bar)


treemap         "../data/flare.json" (see bar)

Data Structures

As detailed in _data_formats_*, the examples in the D3 distribution
use a variety of data structures (eg, tables, graphs) and formats
(eg, CSV, JSON).  This note examines common data structures.


Arrays

  Each CSV file encodes a rectangular array.  The first row is
  used for headings; remaining rows are (generally) used for data.

  Note:  It's possible to define subsidiary encodings (eg, a row
         for default values), but none of the examples do this.
         (JSON is generally a better choice for complex data.)

  Two examples (horizon, qq) use one-dimensional JSON arrays.


Hashes

  Two examples (choropleth, horizon) use one-dimensional hashes.


Mixed

  * Geog_1 - geographical information

    Eight examples (albers, azimuthal, bonne, cartogram, great-arc,
    mercator, node-canvas, symbol-map) use this format, as found in
    "../data/{us-*,world-*}.json".

  * Graph_1 - hash of (nodes, links) arrays of hashes

    One example (force) uses this format, as found in "miserables".

  * Hash_1 - vector of attribute hashes

    A few examples (bullet, bundle, marimekko) use this format,
    as found in "../data/{flare-imports,marimekko}.json" and
    "bullets.json".

    One example (splom) uses a slightly expanded format, as found
    in "flowers.json".
    
  * List_1 - vector of numbers

    Two examples (kde, qq) use this format, as found in
    "../data/faithful.json".

  * Tree_1 - ???

    Seven examples (bar, bubble, cluster, pack, partition, tree,
    treemap) use this format, as found in "../data/flare.json".