MATLAB Figure Reference: histogram2d Traces

A histogram2d trace is a struct inside fig.data which has type equal to 'histogram2d'. This section lists all of the valid keys that a histogram2d struct can contain.

The sample data from which statistics are computed is set in `x` and `y` (where `x` and `y` represent marginal distributions, binning is set in `xbins` and `ybins` in this case) or `z` (where `z` represent the 2D distribution and binning set, binning is set by `x` and `y` in this case). The resulting distribution is visualized as a heatmap.

  • type
    Parent: data[type=histogram2d]
    Type: 'histogram2d'
  • name
    Parent: data[type=histogram2d]
    Type: string

    Sets the trace name. The trace name appears as the legend item and on hover.

  • visible
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( true | false | 'legendonly' )
    Default: true

    Determines whether or not this trace is visible. If 'legendonly', the trace is not drawn, but can appear as a legend item (provided that the legend itself is visible).

  • showlegend
    Parent: data[type=histogram2d]
    Type: boolean

    Determines whether or not an item corresponding to this trace is shown in the legend.

  • legend
    Parent: data[type=histogram2d]
    Type: subplotid
    Default: legend

    Sets the reference to a legend to show this trace in. References to these legends are 'legend', 'legend2', 'legend3', etc. Settings for these legends are set in the layout, under `layout.legend`, `layout.legend2`, etc.

  • legendrank
    Parent: data[type=histogram2d]
    Type: number
    Default: 1000

    Sets the legend rank for this trace. Items and groups with smaller ranks are presented on top/left side while with 'reversed' `legend.traceorder` they are on bottom/right side. The default legendrank is 1000, so that you can use ranks less than 1000 to place certain items before all unranked items, and ranks greater than 1000 to go after all unranked items. When having unranked or equal rank items shapes would be displayed after traces i.e. according to their order in data and layout.

  • legendgroup
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Sets the legend group for this trace. Traces and shapes part of the same legend group hide/show at the same time when toggling legend items.

  • legendgrouptitle
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • font
      Parent: data[type=histogram2d].legendgrouptitle
      Type: struct containing one or more of the keys listed below.

      Sets this legend group's title font.

      • color
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: color
      • family
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: string

        HTML font family - the typeface that will be applied by the web browser. The web browser will only be able to apply a font if it is available on the system which it operates. Provide multiple font families, separated by commas, to indicate the preference in which to apply fonts if they aren't available on the system. The Chart Studio Cloud (at https://chart-studio.plotly.com or on-premise) generates images on a server, where only a select number of fonts are installed and supported. These include 'Arial', 'Balto', 'Courier New', 'Droid Sans', 'Droid Serif', 'Droid Sans Mono', 'Gravitas One', 'Old Standard TT', 'Open Sans', 'Overpass', 'PT Sans Narrow', 'Raleway', 'Times New Roman'.

      • lineposition
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: flaglist string. Any combination of 'under', 'over', 'through' joined with a '+' OR 'none'.
        Examples: 'under', 'over', 'under+over', 'under+over+through', 'none'
        Default: 'none'

        Sets the kind of decoration line(s) with text, such as an 'under', 'over' or 'through' as well as combinations e.g. 'under+over', etc.

      • shadow
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: string
        Default: 'none'

        Sets the shape and color of the shadow behind text. 'auto' places minimal shadow and applies contrast text font color. See https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow for additional options.

      • size
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: number greater than or equal to 1
      • style
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: enumerated , one of ( 'normal' | 'italic' )
        Default: 'normal'

        Sets whether a font should be styled with a normal or italic face from its family.

      • textcase
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: enumerated , one of ( 'normal' | 'word caps' | 'upper' | 'lower' )
        Default: 'normal'

        Sets capitalization of text. It can be used to make text appear in all-uppercase or all-lowercase, or with each word capitalized.

      • variant
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: enumerated , one of ( 'normal' | 'small-caps' | 'all-small-caps' | 'all-petite-caps' | 'petite-caps' | 'unicase' )
        Default: 'normal'

        Sets the variant of the font.

      • weight
        Parent: data[type=histogram2d].legendgrouptitle.font
        Type: integer between or equal to 1 and 1000
        Default: normal

        Sets the weight (or boldness) of the font.

    • text
      Parent: data[type=histogram2d].legendgrouptitle
      Type: string
      Default: ''

      Sets the title of the legend group.

  • legendwidth
    Parent: data[type=histogram2d]
    Type: number greater than or equal to 0

    Sets the width (in px or fraction) of the legend for this trace.

  • opacity
    Parent: data[type=histogram2d]
    Type: number between or equal to 0 and 1
    Default: 1

    Sets the opacity of the trace.

  • ids
    Parent: data[type=histogram2d]
    Type: array

    Assigns id labels to each datum. These ids for object constancy of data points during animation. Should be an array of strings, not numbers or any other type.

  • x
    Parent: data[type=histogram2d]
    Type: array

    Sets the sample data to be binned on the x axis.

  • xgap
    Parent: data[type=histogram2d]
    Type: number greater than or equal to 0
    Default: 0

    Sets the horizontal gap (in pixels) between bricks.

  • y
    Parent: data[type=histogram2d]
    Type: array

    Sets the sample data to be binned on the y axis.

  • ygap
    Parent: data[type=histogram2d]
    Type: number greater than or equal to 0
    Default: 0

    Sets the vertical gap (in pixels) between bricks.

  • z
    Parent: data[type=histogram2d]
    Type: array

    Sets the aggregation data.

  • texttemplate
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Template string used for rendering the information text that appear on points. Note that this will override `textinfo`. Variables are inserted using %{variable}, for example "y: %{y}". Numbers are formatted using d3-format's syntax %{variable:d3-format}, for example "Price: %{y:$.2f}". https://github.com/d3/d3-format/tree/v1.4.5#d3-format for details on the formatting syntax. Dates are formatted using d3-time-format's syntax %{variable|d3-time-format}, for example "Day: %{2019-01-01|%A}". https://github.com/d3/d3-time-format/tree/v2.2.3#locale_format for details on the date formatting syntax. Every attributes that can be specified per-point (the ones that are `arrayOk: true`) are available. Finally, the template string has access to variable `z`

  • hoverinfo
    Parent: data[type=histogram2d]
    Type: flaglist string. Any combination of 'x', 'y', 'z', 'text', 'name' joined with a '+' OR 'all' or 'none' or 'skip'.
    Examples: 'x', 'y', 'x+y', 'x+y+z', 'all'
    Default: 'all'

    Determines which trace information appear on hover. If `none` or `skip` are set, no information is displayed upon hovering. But, if `none` is set, click and hover events are still fired.

  • hovertemplate
    Parent: data[type=histogram2d]
    Type: string or array of strings
    Default: ''

    Template string used for rendering the information that appear on hover box. Note that this will override `hoverinfo`. Variables are inserted using %{variable}, for example "y: %{y}" as well as %{xother}, {%_xother}, {%_xother_}, {%xother_}. When showing info for several points, 'xother' will be added to those with different x positions from the first point. An underscore before or after '(x|y)other' will add a space on that side, only when this field is shown. Numbers are formatted using d3-format's syntax %{variable:d3-format}, for example "Price: %{y:$.2f}". https://github.com/d3/d3-format/tree/v1.4.5#d3-format for details on the formatting syntax. Dates are formatted using d3-time-format's syntax %{variable|d3-time-format}, for example "Day: %{2019-01-01|%A}". https://github.com/d3/d3-time-format/tree/v2.2.3#locale_format for details on the date formatting syntax. The variables available in `hovertemplate` are the ones emitted as event data described at this link https://plotly.com/javascript/plotlyjs-events/#event-data. Additionally, every attributes that can be specified per-point (the ones that are `arrayOk: true`) are available. Finally, the template string has access to variable `z` Anything contained in tag `<extra>` is displayed in the secondary box, for example "<extra>{fullData.name}</extra>". To hide the secondary box completely, use an empty tag `<extra></extra>`.

  • xhoverformat
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Sets the hover text formatting rulefor `x` using d3 formatting mini-languages which are very similar to those in Python. For numbers, see: https://github.com/d3/d3-format/tree/v1.4.5#d3-format. And for dates see: https://github.com/d3/d3-time-format/tree/v2.2.3#locale_format. We add two items to d3's date formatter: '%h' for half of the year as a decimal number as well as '%{n}f' for fractional seconds with n digits. For example, '2016-10-13 09:15:23.456' with tickformat '%H~%M~%S.%2f' would display '09~15~23.46'By default the values are formatted using `xaxis.hoverformat`.

  • yhoverformat
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Sets the hover text formatting rulefor `y` using d3 formatting mini-languages which are very similar to those in Python. For numbers, see: https://github.com/d3/d3-format/tree/v1.4.5#d3-format. And for dates see: https://github.com/d3/d3-time-format/tree/v2.2.3#locale_format. We add two items to d3's date formatter: '%h' for half of the year as a decimal number as well as '%{n}f' for fractional seconds with n digits. For example, '2016-10-13 09:15:23.456' with tickformat '%H~%M~%S.%2f' would display '09~15~23.46'By default the values are formatted using `yaxis.hoverformat`.

  • meta
    Parent: data[type=histogram2d]
    Type: number or categorical coordinate string

    Assigns extra meta information associated with this trace that can be used in various text attributes. Attributes such as trace `name`, graph, axis and colorbar `title.text`, annotation `text` `rangeselector`, `updatemenues` and `sliders` `label` text all support `meta`. To access the trace `meta` values in an attribute in the same trace, simply use `%{meta[i]}` where `i` is the index or key of the `meta` item in question. To access trace `meta` in layout attributes, use `%{data[n[.meta[i]}` where `i` is the index or key of the `meta` and `n` is the trace index.

  • customdata
    Parent: data[type=histogram2d]
    Type: array

    Assigns extra data each datum. This may be useful when listening to hover, click and selection events. Note that, 'scatter' traces also appends customdata items in the markers DOM elements

  • xaxis
    Parent: data[type=histogram2d]
    Type: subplotid
    Default: x

    Sets a reference between this trace's x coordinates and a 2D cartesian x axis. If 'x' (the default value), the x coordinates refer to `layout.xaxis`. If 'x2', the x coordinates refer to `layout.xaxis2`, and so on.

  • yaxis
    Parent: data[type=histogram2d]
    Type: subplotid
    Default: y

    Sets a reference between this trace's y coordinates and a 2D cartesian y axis. If 'y' (the default value), the y coordinates refer to `layout.yaxis`. If 'y2', the y coordinates refer to `layout.yaxis2`, and so on.

  • coloraxis
    Parent: data[type=histogram2d]
    Type: subplotid

    Sets a reference to a shared color axis. References to these shared color axes are 'coloraxis', 'coloraxis2', 'coloraxis3', etc. Settings for these shared color axes are set in the layout, under `layout.coloraxis`, `layout.coloraxis2`, etc. Note that multiple color scales can be linked to the same color axis.

  • histfunc
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( 'count' | 'sum' | 'avg' | 'min' | 'max' )
    Default: 'count'

    Specifies the binning function used for this histogram trace. If 'count', the histogram values are computed by counting the number of values lying inside each bin. If 'sum', 'avg', 'min', 'max', the histogram values are computed using the sum, the average, the minimum or the maximum of the values lying inside each bin respectively.

  • histnorm
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( '' | 'percent' | 'probability' | 'density' | 'probability density' )
    Default: ''

    Specifies the type of normalization used for this histogram trace. If '', the span of each bar corresponds to the number of occurrences (i.e. the number of data points lying inside the bins). If 'percent' / 'probability', the span of each bar corresponds to the percentage / fraction of occurrences with respect to the total number of sample points (here, the sum of all bin HEIGHTS equals 100% / 1). If 'density', the span of each bar corresponds to the number of occurrences in a bin divided by the size of the bin interval (here, the sum of all bin AREAS equals the total number of sample points). If 'probability density', the area of each bar corresponds to the probability that an event will fall into the corresponding bin (here, the sum of all bin AREAS equals 1).

  • nbinsx
    Parent: data[type=histogram2d]
    Type: integer greater than or equal to 0
    Default: 0

    Specifies the maximum number of desired bins. This value will be used in an algorithm that will decide the optimal bin size such that the histogram best visualizes the distribution of the data. Ignored if `xbins.size` is provided.

  • nbinsy
    Parent: data[type=histogram2d]
    Type: integer greater than or equal to 0
    Default: 0

    Specifies the maximum number of desired bins. This value will be used in an algorithm that will decide the optimal bin size such that the histogram best visualizes the distribution of the data. Ignored if `ybins.size` is provided.

  • autobinx
    Parent: data[type=histogram2d]
    Type: boolean

    Obsolete: since v1.42 each bin attribute is auto-determined separately and `autobinx` is not needed. However, we accept `autobinx: true` or `false` and will update `xbins` accordingly before deleting `autobinx` from the trace.

  • autobiny
    Parent: data[type=histogram2d]
    Type: boolean

    Obsolete: since v1.42 each bin attribute is auto-determined separately and `autobiny` is not needed. However, we accept `autobiny: true` or `false` and will update `ybins` accordingly before deleting `autobiny` from the trace.

  • bingroup
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Set the `xbingroup` and `ybingroup` default prefix For example, setting a `bingroup` of '1' on two histogram2d traces will make them their x-bins and y-bins match separately.

  • xbingroup
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Set a group of histogram traces which will have compatible x-bin settings. Using `xbingroup`, histogram2d and histogram2dcontour traces (on axes of the same axis type) can have compatible x-bin settings. Note that the same `xbingroup` value can be used to set (1D) histogram `bingroup`

  • xbins
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • end
      Parent: data[type=histogram2d].xbins
      Type: number or categorical coordinate string

      Sets the end value for the x axis bins. The last bin may not end exactly at this value, we increment the bin edge by `size` from `start` until we reach or exceed `end`. Defaults to the maximum data value. Like `start`, for dates use a date string, and for category data `end` is based on the category serial numbers.

    • size
      Parent: data[type=histogram2d].xbins
      Type: number or categorical coordinate string

      Sets the size of each x axis bin. Default behavior: If `nbinsx` is 0 or omitted, we choose a nice round bin size such that the number of bins is about the same as the typical number of samples in each bin. If `nbinsx` is provided, we choose a nice round bin size giving no more than that many bins. For date data, use milliseconds or 'M<n>' for months, as in `axis.dtick`. For category data, the number of categories to bin together (always defaults to 1).

    • start
      Parent: data[type=histogram2d].xbins
      Type: number or categorical coordinate string

      Sets the starting value for the x axis bins. Defaults to the minimum data value, shifted down if necessary to make nice round values and to remove ambiguous bin edges. For example, if most of the data is integers we shift the bin edges 0.5 down, so a `size` of 5 would have a default `start` of -0.5, so it is clear that 0-4 are in the first bin, 5-9 in the second, but continuous data gets a start of 0 and bins [0,5), [5,10) etc. Dates behave similarly, and `start` should be a date string. For category data, `start` is based on the category serial numbers, and defaults to -0.5.

  • ybingroup
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Set a group of histogram traces which will have compatible y-bin settings. Using `ybingroup`, histogram2d and histogram2dcontour traces (on axes of the same axis type) can have compatible y-bin settings. Note that the same `ybingroup` value can be used to set (1D) histogram `bingroup`

  • ybins
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • end
      Parent: data[type=histogram2d].ybins
      Type: number or categorical coordinate string

      Sets the end value for the y axis bins. The last bin may not end exactly at this value, we increment the bin edge by `size` from `start` until we reach or exceed `end`. Defaults to the maximum data value. Like `start`, for dates use a date string, and for category data `end` is based on the category serial numbers.

    • size
      Parent: data[type=histogram2d].ybins
      Type: number or categorical coordinate string

      Sets the size of each y axis bin. Default behavior: If `nbinsy` is 0 or omitted, we choose a nice round bin size such that the number of bins is about the same as the typical number of samples in each bin. If `nbinsy` is provided, we choose a nice round bin size giving no more than that many bins. For date data, use milliseconds or 'M<n>' for months, as in `axis.dtick`. For category data, the number of categories to bin together (always defaults to 1).

    • start
      Parent: data[type=histogram2d].ybins
      Type: number or categorical coordinate string

      Sets the starting value for the y axis bins. Defaults to the minimum data value, shifted down if necessary to make nice round values and to remove ambiguous bin edges. For example, if most of the data is integers we shift the bin edges 0.5 down, so a `size` of 5 would have a default `start` of -0.5, so it is clear that 0-4 are in the first bin, 5-9 in the second, but continuous data gets a start of 0 and bins [0,5), [5,10) etc. Dates behave similarly, and `start` should be a date string. For category data, `start` is based on the category serial numbers, and defaults to -0.5.

  • marker
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • color
      Parent: data[type=histogram2d].marker
      Type: array

      Sets the aggregation data.

  • textfont
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.

    Sets the text font.

    • color
      Parent: data[type=histogram2d].textfont
      Type: color
      Default: 'auto'
    • family
      Parent: data[type=histogram2d].textfont
      Type: string

      HTML font family - the typeface that will be applied by the web browser. The web browser will only be able to apply a font if it is available on the system which it operates. Provide multiple font families, separated by commas, to indicate the preference in which to apply fonts if they aren't available on the system. The Chart Studio Cloud (at https://chart-studio.plotly.com or on-premise) generates images on a server, where only a select number of fonts are installed and supported. These include 'Arial', 'Balto', 'Courier New', 'Droid Sans', 'Droid Serif', 'Droid Sans Mono', 'Gravitas One', 'Old Standard TT', 'Open Sans', 'Overpass', 'PT Sans Narrow', 'Raleway', 'Times New Roman'.

    • lineposition
      Parent: data[type=histogram2d].textfont
      Type: flaglist string. Any combination of 'under', 'over', 'through' joined with a '+' OR 'none'.
      Examples: 'under', 'over', 'under+over', 'under+over+through', 'none'
      Default: 'none'

      Sets the kind of decoration line(s) with text, such as an 'under', 'over' or 'through' as well as combinations e.g. 'under+over', etc.

    • shadow
      Parent: data[type=histogram2d].textfont
      Type: string
      Default: 'none'

      Sets the shape and color of the shadow behind text. 'auto' places minimal shadow and applies contrast text font color. See https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow for additional options.

    • size
      Parent: data[type=histogram2d].textfont
      Type: number greater than or equal to 1
      Default: 'auto'
    • style
      Parent: data[type=histogram2d].textfont
      Type: enumerated , one of ( 'normal' | 'italic' )
      Default: 'normal'

      Sets whether a font should be styled with a normal or italic face from its family.

    • textcase
      Parent: data[type=histogram2d].textfont
      Type: enumerated , one of ( 'normal' | 'word caps' | 'upper' | 'lower' )
      Default: 'normal'

      Sets capitalization of text. It can be used to make text appear in all-uppercase or all-lowercase, or with each word capitalized.

    • variant
      Parent: data[type=histogram2d].textfont
      Type: enumerated , one of ( 'normal' | 'small-caps' | 'all-small-caps' | 'all-petite-caps' | 'petite-caps' | 'unicase' )
      Default: 'normal'

      Sets the variant of the font.

    • weight
      Parent: data[type=histogram2d].textfont
      Type: integer between or equal to 1 and 1000
      Default: normal

      Sets the weight (or boldness) of the font.

  • colorbar
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • bgcolor
      Parent: data[type=histogram2d].colorbar
      Type: color
      Default: 'rgba(0,0,0,0)'

      Sets the color of padded area.

    • bordercolor
      Parent: data[type=histogram2d].colorbar
      Type: color
      Default: '#444'

      Sets the axis line color.

    • borderwidth
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 0

      Sets the width (in px) or the border enclosing this color bar.

    • dtick
      Parent: data[type=histogram2d].colorbar
      Type: number or categorical coordinate string

      Sets the step in-between ticks on this axis. Use with `tick0`. Must be a positive number, or special strings available to 'log' and 'date' axes. If the axis `type` is 'log', then ticks are set every 10^(n'dtick) where n is the tick number. For example, to set a tick mark at 1, 10, 100, 1000, ... set dtick to 1. To set tick marks at 1, 100, 10000, ... set dtick to 2. To set tick marks at 1, 5, 25, 125, 625, 3125, ... set dtick to log_10(5), or 0.69897000433. 'log' has several special values; 'L<f>', where `f` is a positive number, gives ticks linearly spaced in value (but not position). For example `tick0` = 0.1, `dtick` = 'L0.5' will put ticks at 0.1, 0.6, 1.1, 1.6 etc. To show powers of 10 plus small digits between, use 'D1' (all digits) or 'D2' (only 2 and 5). `tick0` is ignored for 'D1' and 'D2'. If the axis `type` is 'date', then you must convert the time to milliseconds. For example, to set the interval between ticks to one day, set `dtick` to 86400000.0. 'date' also has special values 'M<n>' gives ticks spaced by a number of months. `n` must be a positive integer. To set ticks on the 15th of every third month, set `tick0` to '2000-01-15' and `dtick` to 'M3'. To set ticks every 4 years, set `dtick` to 'M48'

    • exponentformat
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'none' | 'e' | 'E' | 'power' | 'SI' | 'B' )
      Default: 'B'

      Determines a formatting rule for the tick exponents. For example, consider the number 1,000,000,000. If 'none', it appears as 1,000,000,000. If 'e', 1e+9. If 'E', 1E+9. If 'power', 1x10^9 (with 9 in a super script). If 'SI', 1G. If 'B', 1B.

    • labelalias
      Parent: data[type=histogram2d].colorbar
      Type: number or categorical coordinate string

      Replacement text for specific tick or hover labels. For example using {US: 'USA', CA: 'Canada'} changes US to USA and CA to Canada. The labels we would have shown must match the keys exactly, after adding any tickprefix or ticksuffix. For negative numbers the minus sign symbol used (U+2212) is wider than the regular ascii dash. That means you need to use −1 instead of -1. labelalias can be used with any axis type, and both keys (if needed) and values (if desired) can include html-like tags or MathJax.

    • len
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 1

      Sets the length of the color bar This measure excludes the padding of both ends. That is, the color bar length is this length minus the padding on both ends.

    • lenmode
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'fraction' | 'pixels' )
      Default: 'fraction'

      Determines whether this color bar's length (i.e. the measure in the color variation direction) is set in units of plot 'fraction' or in 'pixels. Use `len` to set the value.

    • minexponent
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 3

      Hide SI prefix for 10^n if |n| is below this number. This only has an effect when `tickformat` is 'SI' or 'B'.

    • nticks
      Parent: data[type=histogram2d].colorbar
      Type: integer greater than or equal to 0
      Default: 0

      Specifies the maximum number of ticks for the particular axis. The actual number of ticks will be chosen automatically to be less than or equal to `nticks`. Has an effect only if `tickmode` is set to 'auto'.

    • orientation
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'h' | 'v' )
      Default: 'v'

      Sets the orientation of the colorbar.

    • outlinecolor
      Parent: data[type=histogram2d].colorbar
      Type: color
      Default: '#444'

      Sets the axis line color.

    • outlinewidth
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 1

      Sets the width (in px) of the axis line.

    • separatethousands
      Parent: data[type=histogram2d].colorbar
      Type: boolean

      If "true", even 4-digit integers are separated

    • showexponent
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'all' | 'first' | 'last' | 'none' )
      Default: 'all'

      If 'all', all exponents are shown besides their significands. If 'first', only the exponent of the first tick is shown. If 'last', only the exponent of the last tick is shown. If 'none', no exponents appear.

    • showticklabels
      Parent: data[type=histogram2d].colorbar
      Type: boolean
      Default: true

      Determines whether or not the tick labels are drawn.

    • showtickprefix
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'all' | 'first' | 'last' | 'none' )
      Default: 'all'

      If 'all', all tick labels are displayed with a prefix. If 'first', only the first tick is displayed with a prefix. If 'last', only the last tick is displayed with a suffix. If 'none', tick prefixes are hidden.

    • showticksuffix
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'all' | 'first' | 'last' | 'none' )
      Default: 'all'

      Same as `showtickprefix` but for tick suffixes.

    • thickness
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 30

      Sets the thickness of the color bar This measure excludes the size of the padding, ticks and labels.

    • thicknessmode
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'fraction' | 'pixels' )
      Default: 'pixels'

      Determines whether this color bar's thickness (i.e. the measure in the constant color direction) is set in units of plot 'fraction' or in 'pixels'. Use `thickness` to set the value.

    • tick0
      Parent: data[type=histogram2d].colorbar
      Type: number or categorical coordinate string

      Sets the placement of the first tick on this axis. Use with `dtick`. If the axis `type` is 'log', then you must take the log of your starting tick (e.g. to set the starting tick to 100, set the `tick0` to 2) except when `dtick`='L<f>' (see `dtick` for more info). If the axis `type` is 'date', it should be a date string, like date data. If the axis `type` is 'category', it should be a number, using the scale where each category is assigned a serial number from zero in the order it appears.

    • tickangle
      Parent: data[type=histogram2d].colorbar
      Type: angle
      Default: 'auto'

      Sets the angle of the tick labels with respect to the horizontal. For example, a `tickangle` of -90 draws the tick labels vertically.

    • tickcolor
      Parent: data[type=histogram2d].colorbar
      Type: color
      Default: '#444'

      Sets the tick color.

    • tickfont
      Parent: data[type=histogram2d].colorbar
      Type: struct containing one or more of the keys listed below.

      Sets the color bar's tick label font

      • color
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: color
      • family
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: string

        HTML font family - the typeface that will be applied by the web browser. The web browser will only be able to apply a font if it is available on the system which it operates. Provide multiple font families, separated by commas, to indicate the preference in which to apply fonts if they aren't available on the system. The Chart Studio Cloud (at https://chart-studio.plotly.com or on-premise) generates images on a server, where only a select number of fonts are installed and supported. These include 'Arial', 'Balto', 'Courier New', 'Droid Sans', 'Droid Serif', 'Droid Sans Mono', 'Gravitas One', 'Old Standard TT', 'Open Sans', 'Overpass', 'PT Sans Narrow', 'Raleway', 'Times New Roman'.

      • lineposition
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: flaglist string. Any combination of 'under', 'over', 'through' joined with a '+' OR 'none'.
        Examples: 'under', 'over', 'under+over', 'under+over+through', 'none'
        Default: 'none'

        Sets the kind of decoration line(s) with text, such as an 'under', 'over' or 'through' as well as combinations e.g. 'under+over', etc.

      • shadow
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: string
        Default: 'none'

        Sets the shape and color of the shadow behind text. 'auto' places minimal shadow and applies contrast text font color. See https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow for additional options.

      • size
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: number greater than or equal to 1
      • style
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: enumerated , one of ( 'normal' | 'italic' )
        Default: 'normal'

        Sets whether a font should be styled with a normal or italic face from its family.

      • textcase
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: enumerated , one of ( 'normal' | 'word caps' | 'upper' | 'lower' )
        Default: 'normal'

        Sets capitalization of text. It can be used to make text appear in all-uppercase or all-lowercase, or with each word capitalized.

      • variant
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: enumerated , one of ( 'normal' | 'small-caps' | 'all-small-caps' | 'all-petite-caps' | 'petite-caps' | 'unicase' )
        Default: 'normal'

        Sets the variant of the font.

      • weight
        Parent: data[type=histogram2d].colorbar.tickfont
        Type: integer between or equal to 1 and 1000
        Default: normal

        Sets the weight (or boldness) of the font.

    • tickformat
      Parent: data[type=histogram2d].colorbar
      Type: string
      Default: ''

      Sets the tick label formatting rule using d3 formatting mini-languages which are very similar to those in Python. For numbers, see: https://github.com/d3/d3-format/tree/v1.4.5#d3-format. And for dates see: https://github.com/d3/d3-time-format/tree/v2.2.3#locale_format. We add two items to d3's date formatter: '%h' for half of the year as a decimal number as well as '%{n}f' for fractional seconds with n digits. For example, '2016-10-13 09:15:23.456' with tickformat '%H~%M~%S.%2f' would display '09~15~23.46'

    • tickformatstops
      Parent: data[type=histogram2d].colorbar
      Type: cell array of struct where each struct has one or more of the keys listed below.
      • dtickrange
        Parent: data[type=histogram2d].colorbar.tickformatstops[]
        Type: cell array

        range ['min', 'max'], where 'min', 'max' - dtick values which describe some zoom level, it is possible to omit 'min' or 'max' value by passing 'null'

      • enabled
        Parent: data[type=histogram2d].colorbar.tickformatstops[]
        Type: boolean
        Default: true

        Determines whether or not this stop is used. If `false`, this stop is ignored even within its `dtickrange`.

      • name
        Parent: data[type=histogram2d].colorbar.tickformatstops[]
        Type: string

        When used in a template, named items are created in the output figure in addition to any items the figure already has in this array. You can modify these items in the output figure by making your own item with `templateitemname` matching this `name` alongside your modifications (including `visible: false` or `enabled: false` to hide it). Has no effect outside of a template.

      • templateitemname
        Parent: data[type=histogram2d].colorbar.tickformatstops[]
        Type: string

        Used to refer to a named item in this array in the template. Named items from the template will be created even without a matching item in the input figure, but you can modify one by making an item with `templateitemname` matching its `name`, alongside your modifications (including `visible: false` or `enabled: false` to hide it). If there is no template or no matching item, this item will be hidden unless you explicitly show it with `visible: true`.

      • value
        Parent: data[type=histogram2d].colorbar.tickformatstops[]
        Type: string
        Default: ''

        string - dtickformat for described zoom level, the same as 'tickformat'

    • ticklabeloverflow
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'allow' | 'hide past div' | 'hide past domain' )

      Determines how we handle tick labels that would overflow either the graph div or the domain of the axis. The default value for inside tick labels is 'hide past domain'. In other cases the default is 'hide past div'.

    • ticklabelposition
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'outside' | 'inside' | 'outside top' | 'inside top' | 'outside left' | 'inside left' | 'outside right' | 'inside right' | 'outside bottom' | 'inside bottom' )
      Default: 'outside'

      Determines where tick labels are drawn relative to the ticks. Left and right options are used when `orientation` is 'h', top and bottom when `orientation` is 'v'.

    • ticklabelstep
      Parent: data[type=histogram2d].colorbar
      Type: integer greater than or equal to 1
      Default: 1

      Sets the spacing between tick labels as compared to the spacing between ticks. A value of 1 (default) means each tick gets a label. A value of 2 means shows every 2nd label. A larger value n means only every nth tick is labeled. `tick0` determines which labels are shown. Not implemented for axes with `type` 'log' or 'multicategory', or when `tickmode` is 'array'.

    • ticklen
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 5

      Sets the tick length (in px).

    • tickmode
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'auto' | 'linear' | 'array' )

      Sets the tick mode for this axis. If 'auto', the number of ticks is set via `nticks`. If 'linear', the placement of the ticks is determined by a starting position `tick0` and a tick step `dtick` ('linear' is the default value if `tick0` and `dtick` are provided). If 'array', the placement of the ticks is set via `tickvals` and the tick text is `ticktext`. ('array' is the default value if `tickvals` is provided).

    • tickprefix
      Parent: data[type=histogram2d].colorbar
      Type: string
      Default: ''

      Sets a tick label prefix.

    • ticks
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'outside' | 'inside' | '' )
      Default: ''

      Determines whether ticks are drawn or not. If '', this axis' ticks are not drawn. If 'outside' ('inside'), this axis' are drawn outside (inside) the axis lines.

    • ticksuffix
      Parent: data[type=histogram2d].colorbar
      Type: string
      Default: ''

      Sets a tick label suffix.

    • ticktext
      Parent: data[type=histogram2d].colorbar
      Type: array

      Sets the text displayed at the ticks position via `tickvals`. Only has an effect if `tickmode` is set to 'array'. Used with `tickvals`.

    • tickvals
      Parent: data[type=histogram2d].colorbar
      Type: array

      Sets the values at which ticks on this axis appear. Only has an effect if `tickmode` is set to 'array'. Used with `ticktext`.

    • tickwidth
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 1

      Sets the tick width (in px).

    • title
      Parent: data[type=histogram2d].colorbar
      Type: struct containing one or more of the keys listed below.
      • font
        Parent: data[type=histogram2d].colorbar.title
        Type: struct containing one or more of the keys listed below.

        Sets this color bar's title font. Note that the title's font used to be set by the now deprecated `titlefont` attribute.

        • color
          Parent: data[type=histogram2d].colorbar.title.font
          Type: color
        • family
          Parent: data[type=histogram2d].colorbar.title.font
          Type: string

          HTML font family - the typeface that will be applied by the web browser. The web browser will only be able to apply a font if it is available on the system which it operates. Provide multiple font families, separated by commas, to indicate the preference in which to apply fonts if they aren't available on the system. The Chart Studio Cloud (at https://chart-studio.plotly.com or on-premise) generates images on a server, where only a select number of fonts are installed and supported. These include 'Arial', 'Balto', 'Courier New', 'Droid Sans', 'Droid Serif', 'Droid Sans Mono', 'Gravitas One', 'Old Standard TT', 'Open Sans', 'Overpass', 'PT Sans Narrow', 'Raleway', 'Times New Roman'.

        • lineposition
          Parent: data[type=histogram2d].colorbar.title.font
          Type: flaglist string. Any combination of 'under', 'over', 'through' joined with a '+' OR 'none'.
          Examples: 'under', 'over', 'under+over', 'under+over+through', 'none'
          Default: 'none'

          Sets the kind of decoration line(s) with text, such as an 'under', 'over' or 'through' as well as combinations e.g. 'under+over', etc.

        • shadow
          Parent: data[type=histogram2d].colorbar.title.font
          Type: string
          Default: 'none'

          Sets the shape and color of the shadow behind text. 'auto' places minimal shadow and applies contrast text font color. See https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow for additional options.

        • size
          Parent: data[type=histogram2d].colorbar.title.font
          Type: number greater than or equal to 1
        • style
          Parent: data[type=histogram2d].colorbar.title.font
          Type: enumerated , one of ( 'normal' | 'italic' )
          Default: 'normal'

          Sets whether a font should be styled with a normal or italic face from its family.

        • textcase
          Parent: data[type=histogram2d].colorbar.title.font
          Type: enumerated , one of ( 'normal' | 'word caps' | 'upper' | 'lower' )
          Default: 'normal'

          Sets capitalization of text. It can be used to make text appear in all-uppercase or all-lowercase, or with each word capitalized.

        • variant
          Parent: data[type=histogram2d].colorbar.title.font
          Type: enumerated , one of ( 'normal' | 'small-caps' | 'all-small-caps' | 'all-petite-caps' | 'petite-caps' | 'unicase' )
          Default: 'normal'

          Sets the variant of the font.

        • weight
          Parent: data[type=histogram2d].colorbar.title.font
          Type: integer between or equal to 1 and 1000
          Default: normal

          Sets the weight (or boldness) of the font.

      • side
        Parent: data[type=histogram2d].colorbar.title
        Type: enumerated , one of ( 'right' | 'top' | 'bottom' )

        Determines the location of color bar's title with respect to the color bar. Defaults to 'top' when `orientation` if 'v' and defaults to 'right' when `orientation` if 'h'. Note that the title's location used to be set by the now deprecated `titleside` attribute.

      • text
        Parent: data[type=histogram2d].colorbar.title
        Type: string

        Sets the title of the color bar. Note that before the existence of `title.text`, the title's contents used to be defined as the `title` attribute itself. This behavior has been deprecated.

    • x
      Parent: data[type=histogram2d].colorbar
      Type: number

      Sets the x position with respect to `xref` of the color bar (in plot fraction). When `xref` is 'paper', defaults to 1.02 when `orientation` is 'v' and 0.5 when `orientation` is 'h'. When `xref` is 'container', defaults to '1' when `orientation` is 'v' and 0.5 when `orientation` is 'h'. Must be between '0' and '1' if `xref` is 'container' and between '-2' and '3' if `xref` is 'paper'.

    • xanchor
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'left' | 'center' | 'right' )

      Sets this color bar's horizontal position anchor. This anchor binds the `x` position to the 'left', 'center' or 'right' of the color bar. Defaults to 'left' when `orientation` is 'v' and 'center' when `orientation` is 'h'.

    • xpad
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 10

      Sets the amount of padding (in px) along the x direction.

    • xref
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'container' | 'paper' )
      Default: 'paper'

      Sets the container `x` refers to. 'container' spans the entire `width` of the plot. 'paper' refers to the width of the plotting area only.

    • y
      Parent: data[type=histogram2d].colorbar
      Type: number

      Sets the y position with respect to `yref` of the color bar (in plot fraction). When `yref` is 'paper', defaults to 0.5 when `orientation` is 'v' and 1.02 when `orientation` is 'h'. When `yref` is 'container', defaults to 0.5 when `orientation` is 'v' and 1 when `orientation` is 'h'. Must be between '0' and '1' if `yref` is 'container' and between '-2' and '3' if `yref` is 'paper'.

    • yanchor
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'top' | 'middle' | 'bottom' )

      Sets this color bar's vertical position anchor This anchor binds the `y` position to the 'top', 'middle' or 'bottom' of the color bar. Defaults to 'middle' when `orientation` is 'v' and 'bottom' when `orientation` is 'h'.

    • ypad
      Parent: data[type=histogram2d].colorbar
      Type: number greater than or equal to 0
      Default: 10

      Sets the amount of padding (in px) along the y direction.

    • yref
      Parent: data[type=histogram2d].colorbar
      Type: enumerated , one of ( 'container' | 'paper' )
      Default: 'paper'

      Sets the container `y` refers to. 'container' spans the entire `height` of the plot. 'paper' refers to the height of the plotting area only.

  • autocolorscale
    Parent: data[type=histogram2d]
    Type: boolean

    Determines whether the colorscale is a default palette (`autocolorscale: true`) or the palette determined by `colorscale`. In case `colorscale` is unspecified or `autocolorscale` is true, the default palette will be chosen according to whether numbers in the `color` array are all positive, all negative or mixed.

  • colorscale
    Parent: data[type=histogram2d]
    Type: colorscale

    Sets the colorscale. The colorscale must be an array containing arrays mapping a normalized value to an rgb, rgba, hex, hsl, hsv, or named color string. At minimum, a mapping for the lowest (0) and highest (1) values are required. For example, `[[0, 'rgb(0,0,255)'], [1, 'rgb(255,0,0)']]`. To control the bounds of the colorscale in color space, use `zmin` and `zmax`. Alternatively, `colorscale` may be a palette name string of the following list: Blackbody,Bluered,Blues,Cividis,Earth,Electric,Greens,Greys,Hot,Jet,Picnic,Portland,Rainbow,RdBu,Reds,Viridis,YlGnBu,YlOrRd.

  • showscale
    Parent: data[type=histogram2d]
    Type: boolean
    Default: true

    Determines whether or not a colorbar is displayed for this trace.

  • reversescale
    Parent: data[type=histogram2d]
    Type: boolean

    Reverses the color mapping if true. If true, `zmin` will correspond to the last color in the array and `zmax` will correspond to the first color.

  • zauto
    Parent: data[type=histogram2d]
    Type: boolean
    Default: true

    Determines whether or not the color domain is computed with respect to the input data (here in `z`) or the bounds set in `zmin` and `zmax` Defaults to `false` when `zmin` and `zmax` are set by the user.

  • zhoverformat
    Parent: data[type=histogram2d]
    Type: string
    Default: ''

    Sets the hover text formatting rulefor `z` using d3 formatting mini-languages which are very similar to those in Python. For numbers, see: https://github.com/d3/d3-format/tree/v1.4.5#d3-format.By default the values are formatted using generic number format.

  • zmax
    Parent: data[type=histogram2d]
    Type: number

    Sets the upper bound of the color domain. Value should have the same units as in `z` and if set, `zmin` must be set as well.

  • zmid
    Parent: data[type=histogram2d]
    Type: number

    Sets the mid-point of the color domain by scaling `zmin` and/or `zmax` to be equidistant to this point. Value should have the same units as in `z`. Has no effect when `zauto` is `false`.

  • zmin
    Parent: data[type=histogram2d]
    Type: number

    Sets the lower bound of the color domain. Value should have the same units as in `z` and if set, `zmax` must be set as well.

  • zsmooth
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( 'fast' | 'best' | false )

    Picks a smoothing algorithm use to smooth `z` data.

  • hoverlabel
    Parent: data[type=histogram2d]
    Type: struct containing one or more of the keys listed below.
    • align
      Parent: data[type=histogram2d].hoverlabel
      Type: enumerated or array of enumerateds , one of ( 'left' | 'right' | 'auto' )
      Default: 'auto'

      Sets the horizontal alignment of the text content within hover label box. Has an effect only if the hover label text spans more two or more lines

    • bgcolor
      Parent: data[type=histogram2d].hoverlabel
      Type: color or array of colors

      Sets the background color of the hover labels for this trace

    • bordercolor
      Parent: data[type=histogram2d].hoverlabel
      Type: color or array of colors

      Sets the border color of the hover labels for this trace.

    • font
      Parent: data[type=histogram2d].hoverlabel
      Type: struct containing one or more of the keys listed below.

      Sets the font used in hover labels.

      • color
        Parent: data[type=histogram2d].hoverlabel.font
        Type: color or array of colors
      • family
        Parent: data[type=histogram2d].hoverlabel.font
        Type: string or array of strings

        HTML font family - the typeface that will be applied by the web browser. The web browser will only be able to apply a font if it is available on the system which it operates. Provide multiple font families, separated by commas, to indicate the preference in which to apply fonts if they aren't available on the system. The Chart Studio Cloud (at https://chart-studio.plotly.com or on-premise) generates images on a server, where only a select number of fonts are installed and supported. These include 'Arial', 'Balto', 'Courier New', 'Droid Sans', 'Droid Serif', 'Droid Sans Mono', 'Gravitas One', 'Old Standard TT', 'Open Sans', 'Overpass', 'PT Sans Narrow', 'Raleway', 'Times New Roman'.

      • lineposition
        Parent: data[type=histogram2d].hoverlabel.font
        Type: flaglist string. Any combination of 'under', 'over', 'through' joined with a '+' OR 'none'.
        Examples: 'under', 'over', 'under+over', 'under+over+through', 'none'
        Default: 'none'

        Sets the kind of decoration line(s) with text, such as an 'under', 'over' or 'through' as well as combinations e.g. 'under+over', etc.

      • shadow
        Parent: data[type=histogram2d].hoverlabel.font
        Type: string or array of strings
        Default: 'none'

        Sets the shape and color of the shadow behind text. 'auto' places minimal shadow and applies contrast text font color. See https://developer.mozilla.org/en-US/docs/Web/CSS/text-shadow for additional options.

      • size
        Parent: data[type=histogram2d].hoverlabel.font
        Type: number or array of numbers greater than or equal to 1
      • style
        Parent: data[type=histogram2d].hoverlabel.font
        Type: enumerated or array of enumerateds , one of ( 'normal' | 'italic' )
        Default: 'normal'

        Sets whether a font should be styled with a normal or italic face from its family.

      • textcase
        Parent: data[type=histogram2d].hoverlabel.font
        Type: enumerated or array of enumerateds , one of ( 'normal' | 'word caps' | 'upper' | 'lower' )
        Default: 'normal'

        Sets capitalization of text. It can be used to make text appear in all-uppercase or all-lowercase, or with each word capitalized.

      • variant
        Parent: data[type=histogram2d].hoverlabel.font
        Type: enumerated or array of enumerateds , one of ( 'normal' | 'small-caps' | 'all-small-caps' | 'all-petite-caps' | 'petite-caps' | 'unicase' )
        Default: 'normal'

        Sets the variant of the font.

      • weight
        Parent: data[type=histogram2d].hoverlabel.font
        Type: integer or array of integers between or equal to 1 and 1000
        Default: normal

        Sets the weight (or boldness) of the font.

    • namelength
      Parent: data[type=histogram2d].hoverlabel
      Type: integer or array of integers greater than or equal to -1
      Default: 15

      Sets the default length (in number of characters) of the trace name in the hover labels for all traces. -1 shows the whole name regardless of length. 0-3 shows the first 0-3 characters, and an integer >3 will show the whole name if it is less than that many characters, but if it is longer, will truncate to `namelength - 3` characters and add an ellipsis.

  • xcalendar
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( 'chinese' | 'coptic' | 'discworld' | 'ethiopian' | 'gregorian' | 'hebrew' | 'islamic' | 'jalali' | 'julian' | 'mayan' | 'nanakshahi' | 'nepali' | 'persian' | 'taiwan' | 'thai' | 'ummalqura' )
    Default: 'gregorian'

    Sets the calendar system to use with `x` date data.

  • ycalendar
    Parent: data[type=histogram2d]
    Type: enumerated , one of ( 'chinese' | 'coptic' | 'discworld' | 'ethiopian' | 'gregorian' | 'hebrew' | 'islamic' | 'jalali' | 'julian' | 'mayan' | 'nanakshahi' | 'nepali' | 'persian' | 'taiwan' | 'thai' | 'ummalqura' )
    Default: 'gregorian'

    Sets the calendar system to use with `y` date data.

  • uirevision
    Parent: data[type=histogram2d]
    Type: number or categorical coordinate string

    Controls persistence of some user-driven changes to the trace: `constraintrange` in `parcoords` traces, as well as some `editable: true` modifications such as `name` and `colorbar.title`. Defaults to `layout.uirevision`. Note that other user-driven trace attribute changes are controlled by `layout` attributes: `trace.visible` is controlled by `layout.legend.uirevision`, `selectedpoints` is controlled by `layout.selectionrevision`, and `colorbar.(x|y)` (accessible with `config: {editable: true}`) is controlled by `layout.editrevision`. Trace changes are tracked by `uid`, which only falls back on trace index if no `uid` is provided. So if your app can add/remove traces before the end of the `data` array, such that the same trace has a different index, you can still preserve user-driven changes if you give each trace a `uid` that stays with it as it moves.