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Lets-Plot for Python

v4.3.2

lets_plot.geom_polygon#

lets_plot.geom_polygon(mapping=None, *, data=None, stat=None, position=None, show_legend=None, sampling=None, tooltips=None, map=None, map_join=None, use_crs=None, color_by=None, fill_by=None, **other_args)#

Display a filled closed path defined by the vertex coordinates of individual polygons.

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 Pandas or Polars DataFrame or GeoDataFrame

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=’identity’

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

positionstr or FeatureSpec, default=’identity’

Position adjustment. Either a position adjustment name: ‘dodge’, ‘dodgev’, ‘jitter’, ‘nudge’, ‘jitterdodge’, ‘fill’, ‘stack’ or ‘identity’, or the result of calling a position adjustment function (e.g., position_dodge() etc.).

show_legendbool, default=True

False - do not show legend for this layer.

samplingFeatureSpec

Result of the call to the sampling_xxx() function. To prevent any sampling for this layer pass value “none” (string “none”).

tooltipslayer_tooltips

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

mapGeoDataFrame or Geocoder

Data contains coordinates of polygon vertices on map.

map_joinstr or list

Keys used to join map coordinates with data. First value in pair - column/columns in data. Second value in pair - column/columns in map.

use_crsstr, optional, default=”EPSG:4326” (aka WGS84)

EPSG code of the coordinate reference system (CRS) or the keyword “provided”. If an EPSG code is given, then all the coordinates in GeoDataFrame (see the map parameter) will be projected to this CRS. Specify “provided” to disable any further re-projection and to keep the GeoDataFrame’s original CRS.

color_by{‘fill’, ‘color’, ‘paint_a’, ‘paint_b’, ‘paint_c’}, default=’color’

Define the color aesthetic for the geometry.

fill_by{‘fill’, ‘color’, ‘paint_a’, ‘paint_b’, ‘paint_c’}, default=’fill’

Define the fill aesthetic for the geometry.

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_polygon() draws polygons, which are filled paths. Each vertex of the polygon requires a separate row in the data.

geom_polygon() understands the following aesthetics mappings:

  • x : x-axis coordinates of the vertices of the polygon.

  • y : y-axis coordinates of the vertices of the polygon.

  • alpha : transparency level of a layer. Accept values between 0 and 1.

  • color (colour) : color of the geometry lines. String in the following formats: RGB/RGBA (e.g. “rgb(0, 0, 255)”); HEX (e.g. “#0000FF”); color name (e.g. “red”); role name (“pen”, “paper” or “brush”).

  • fill : fill color. String in the following formats: RGB/RGBA (e.g. “rgb(0, 0, 255)”); HEX (e.g. “#0000FF”); color name (e.g. “red”); role name (“pen”, “paper” or “brush”).

  • size : line width.

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


The data and map parameters of GeoDataFrame type support shapes Polygon and MultiPolygon.

The map parameter of Geocoder type implicitly invokes boundaries() function.


The conventions for the values of map_join parameter are as follows:

  • Joining data and GeoDataFrame object

    Data has a column named ‘State_name’ and GeoDataFrame has a matching column named ‘state’:

    • map_join=[‘State_Name’, ‘state’]

    • map_join=[[‘State_Name’], [‘state’]]

  • Joining data and Geocoder object

    Data has a column named ‘State_name’. The matching key in Geocoder is always ‘state’ (providing it is a state-level geocoder) and can be omitted:

    • map_join=’State_Name’

    • map_join=[‘State_Name’]

  • Joining data by composite key

    Joining by composite key works like in examples above, but instead of using a string for a simple key you need to use an array of strings for a composite key. The names in the composite key must be in the same order as in the US street addresses convention: ‘city’, ‘county’, ‘state’, ‘country’. For example, the data has columns ‘State_name’ and ‘County_name’. Joining with a 2-keys county level Geocoder object (the Geocoder keys ‘county’ and ‘state’ are omitted in this case):

    • map_join=[‘County_name’, ‘State_Name’]

Examples

 1import numpy as np
 2from lets_plot import *
 3LetsPlot.setup_html()
 4n = 7
 5t = np.linspace(0, 2 * np.pi, 2 * n + 1)
 6r = np.concatenate((np.tile([1, .5], n), [1]))
 7data = {'x': r * np.cos(t), 'y': r * np.sin(t)}
 8ggplot(data, aes(x='x', y='y')) + \
 9    geom_polygon() + \
10    coord_fixed()


 1import numpy as np
 2import pandas as pd
 3from scipy.spatial import Voronoi
 4from lets_plot import *
 5LetsPlot.setup_html()
 6n = 30
 7np.random.seed(42)
 8x = np.random.normal(size=n)
 9y = np.random.normal(size=n)
10df = pd.DataFrame({'x': x, 'y': y})
11v = Voronoi(list(zip(x, y)))
12v_df = pd.DataFrame([(i, *v.vertices[v_id]) for i, r in enumerate(v.regions) \
13                                            for v_id in r if any(r) and not -1 in r],
14                    columns=['id', 'x', 'y'])
15ggplot() + \
16    geom_polygon(aes(x='x', y='y', group='id', fill='id'), \
17                 data=v_df, show_legend=False, color='white') + \
18    geom_point(aes(x='x', y='y'), data=df, shape=21, color='black', fill='white') + \
19    scale_fill_discrete() + \
20    coord_fixed()


 1from lets_plot import *
 2from lets_plot.geo_data import *
 3LetsPlot.setup_html()
 4data = {"city": ["New York", "Philadelphia"], \
 5        "est_pop_2019": [8_336_817, 1_584_064]}
 6boundaries = geocode_cities(data["city"]).inc_res().get_boundaries()
 7ggplot() + geom_livemap() + \
 8    geom_polygon(aes(color="city", fill="city"), data=data, map=boundaries, \
 9                 map_join="city", alpha=.2, \
10                 tooltips=layer_tooltips().title('@city')\
11                                          .line('population|@est_pop_2019'))

The geodata is provided by © OpenStreetMap contributors and is made available here under the Open Database License (ODbL).
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