lets_plot.geom_density2d

lets_plot.geom_density2d(mapping=None, *, data=None, stat=None, position=None, show_legend=None, sampling=None, tooltips=None, kernel=None, adjust=None, bw=None, n=None, bins=None, binwidth=None, **other_args)

Display density function contour.

Parameters
mappingFeatureSpec

Set of aesthetic mappings created by aes() function. Aesthetic mappings describe the way that variables in the data are mapped to plot “aesthetics”.

datadict or DataFrame

The data to be displayed in this layer. If None, the default, the data is inherited from the plot data as specified in the call to ggplot.

statstr, default=’density2d’

The statistical transformation to use on the data for this layer, as a string.

positionstr or FeatureSpec

Position adjustment, either as a string (‘identity’, ‘stack’, ‘dodge’, …), or the result of a call to a position adjustment function.

show_legendbool, default=True

False - do not show legend for this layer.

samplingFeatureSpec

Result of the call to the sampling_xxx() function. Value None (or ‘none’) will disable sampling for this layer.

tooltipslayer_tooltips

Result of the call to the layer_tooltips() function. Specifies appearance, style and content.

kernelstr, default=’gaussian’

The kernel we use to calculate the density function. Choose among ‘gaussian’, ‘cosine’, ‘optcosine’, ‘rectangular’ (or ‘uniform’), ‘triangular’, ‘biweight’ (or ‘quartic’), ‘epanechikov’ (or ‘parabolic’).

bwstr or list of float

The method (or exact value) of bandwidth. Either a string (choose among ‘nrd0’ and ‘nrd’), or a float array of length 2.

adjustfloat

Adjust the value of bandwidth my multiplying it. Changes how smooth the frequency curve is.

nlist of int

The number of sampled points for plotting the function (on x and y direction correspondingly).

binsint

Number of levels.

binwidthfloat

Distance between levels.

other_args

Other arguments passed on to the layer. These are often aesthetics settings used to set an aesthetic to a fixed value, like color=’red’, fill=’blue’, size=3 or shape=21. They may also be parameters to the paired geom/stat.

Returns
LayerSpec

Geom object specification.

Notes

geom_density2d() draws density function.

Computed variables:

  • ..group.. : number of density estimate contour line.

geom_density2d() understands the following aesthetics mappings:

  • x : x-axis coordinates.

  • y : y-axis coordinates.

  • alpha : transparency level of a layer. Understands numbers between 0 and 1.

  • color (colour) : color of a geometry lines. Can be continuous or discrete. For continuous value this will be a color gradient between two colors.

  • size : lines width. Defines line width.

  • linetype : type of the line of border. Codes and names: 0 = ‘blank’, 1 = ‘solid’, 2 = ‘dashed’, 3 = ‘dotted’, 4 = ‘dotdash’, 5 = ‘longdash’, 6 = ‘twodash’.


‘density2d’ statistical transformation combined with parameter value contour=False could be used to draw heatmaps (see the example below).

Examples

1import numpy as np
2from lets_plot import *
3LetsPlot.setup_html()
4n = 1000
5np.random.seed(42)
6x = np.random.normal(size=n)
7y = np.random.normal(size=n)
8ggplot({'x': x, 'y': y}, aes('x', 'y')) + \
9    geom_density2d()