Plot

Bar

Turning quantitative values into geometric shapes.

Novem offers 16 types of barcharts but they can be categorized into three main archetypes:

  • bar - regular barchart
  • sbar - stacked barchart
  • gbar - grouped barchart

In addition to the above there is a special aggregate barchart, abar, which will be explained in detail below.

To accommodate horizontal as well as top/bottom anchoring novem further expands the barcharts with two subcategories, horizontal and inverted.

By prepending one of the above type with either h, i or both you can tell the bars to be anchored to the left side h, or right side ih. In addition to anchor a bar to the top (making it "grow" down) just append i to the regular type. e.g. ibar

Below is a comprehensive list of possible barchart types.

/vis/plots/<name>/type

Regular  Horizontal  Inverted  Inverted Horizontal
-------  ----------  --------  -------------------
bar      hbar        ibar      ihbar
sbar     hsbar       isbar     ihsbar
gbar     hgbar       igbar     ihgbar
abar     habar       iabar     ihabar

Barcharts follow a regular novem chart structure as outlined below. For a more detailed introduction to the chart structure please see the chart structure details page.

en_letter_frequency      => Name
├── config               => Configuration options
│   ├── caption          => Caption below chart
│   ├── title            => Title of chart
│   └── type             => bar, sbar, gbar etc...
├── data                 => data to chart
├── description          => Description (meta)
├── name                 => Name (meta)
└── shared               => Sharing information
    ├── +org~group       => Shared with an org group
    ├── @username~group  => Shared with a user group
    └── public           => Shared with everyone


curl -X POST https://api.novem.io/vis/plots/<name>/data \
  -H "Authorization: Bearer <your_token>" \
  --data "@data.csv"

Like most novem charts the primary way to update the barchart is by writing the information you want visualised to the /data endpoint.

Novem will assume that the first column is the data for the category axis and the second column the data for the value axis. By default the category axis would be the x-axis, but this will be flipped in the example of h* and ih* versions.

As mentioned in the introduction there are 3 main types of barcharts available on the novem platform.

Aggregate plots are identical to regular plots, except they represent the sum of the columns for each category label.

The novem barchart offers six outputs, four for the final visualisation and two for the input data. They can all be found under the /files endpoint or by appending the extensions below. For details on the respective output formats please see the api file documentation.

  • pdf - a pdf representation /config/render/orientation orientation of the plot.
  • png - a png representation /config/render/orientation orientation of the plot.
  • txt - a utf-8 textual representation of the plot
  • ansi - a ansi escape sequence colored utf-8 textual representation of the plot
  • csv - a csv file containing the input data
  • xlsx - an xlsx file containing the input data

This section contains a few practical examples on how to use the api and common use cases. For more comprehensive examples we suggest visiting some of our example charts or reading a couple of our getting started with novem blog posts.

Welcome to your first barchart, we'll assume that you have a csv file called en_letter_freq.csv file two columns:

  • Character
  • Frequency

If you want to cheat you can find an example file here : url to en_letter_freq.csv.

# this assumes that the novem client is installed in $PATH

cat en_letter_freq.csv | novem \
-p <name> # -p for plot name will be created or updated
-w config/type "bar" \ # -w for write followed by relative plot path and value
-w config/title "Frequency of letters in the English language" \
-w config/caption "Analysis of entries in the Concise Oxford dictionary "\
"as published by the compilers. The chart above represents "\
"data taken from Pavel Micka's website, which cites "\
"Robert Lewand's Cryptological Mathematics" \
-g url # returns the url
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