Style Histogram

Histogram (v2.0.0+)

How often a sensor's readings fell in each range of values: how long the living room sat below 18 °C this week, or how a response time is spread. It is a history chart like Line, and shares its period, calendar spans, previous and next buttons, statistics, grouping, axes, hover readout and compact layout.

Good for

Seeing where a value spends its time, rather than when: comfort ranges, how often a tank is nearly empty, the spread of a measurement.

Example

type: custom:chartdeck-card
style: histogram
title: Living room this week
period:
  last: 7
  unit: day
entities:
  - entity: sensor.living_room_temperature
    name: Living room

To use this style, set style: histogram (or pick Histogram under Distributions in the editor's Style section). The chart options are in the editor's Chart section.

Sensible defaults

• Bins count time (count: time). History records changes, not samples: a room at 20 °C all day that flickers to 21 °C ten times in a minute has ten rows at 21 and one at 20. Counting rows would say it was mostly 21; adding up how long each value held says 20, which is what the room was. Each value counts until the next reading (the last one until now, or the end of the period), and time spent unavailable counts nothing.
• Bin width is a round number (1, 2 or 5 × 10ⁿ) that gives a number of bins to suit the card's width.
• Bars show each entity's share of its whole (show_as: percent).
• Period: the last 24 hours when period isn't set, as on the line chart.

Options

count: time         # time (default) or readings
show_as: percent    # percent (default) or total
bin_width: 0.5      # bins of this width, edges on its multiples
bins: 10            # or: exactly this many bins, lowest to highest reading (1 to 100)
x_min: 15           # fixed range along the bottom; readings outside it are left out
x_max: 25
bars: side          # side (default) or overlap, for two or more entities
color_by: series    # series (default) or bands

• count: readings counts rows instead of time, for sensors where each reading is an event. The value carried in from before the period, and the copy carried to its right edge, are not counted.
• From long-term statistics (source: statistics) each row counts one period, so a missing row is missing data rather than a long-held value. With group_by set, each group counts for its own length.
• show_as: total draws the hours (or the number of readings) in each bin instead of the share.
• bin_width wins over bins. There are never more than 100 bins: a width that would give more is widened.
• bars: overlap draws several entities over each other, see-through and outlined, instead of side by side in each bin.
• color_by: bands colours each bin by the colour band its middle falls in.
• Per entity, color sets the bar colour.

Hovering or touching a bin shades it and lists each entity's share and time (or readings) there.

In the editor: Count, Show as, Number of bins, Bin width, Lowest value across, Highest value across, Two or more entities, Colour and Value labels along the bottom. Each entity has a Bar colour.

Everything else

The period, calendar spans, source, grouping, axes, gridlines, hover and compact layout are the same as on the line chart. See Line for each one.

Layout: one chart for the whole card. Every shared option is described on the Options page.

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