Point#
point
mark represents each data point with a symbol. Point marks are commonly used in visualizations like scatter plots.
Point Mark Properties#
Click to show code
import altair as alt
from vega_datasets import data
source = data.cars()
shape_select = alt.binding_select(
options=[
"arrow",
"circle",
"square",
"cross",
"diamond",
"triangle",
"triangle-up",
"triangle-down",
"triangle-right",
"triangle-left",
"wedge",
"stroke",
"M-1,-1H1V1H-1Z",
"M0,.5L.6,.8L.5,.1L1,-.3L.3,-.4L0,-1L-.3,-.4L-1,-.3L-.5,.1L-.6,.8L0,.5Z",
],
name="shape",
)
shape_var = alt.param(bind=shape_select, value="circle")
angle_slider = alt.binding_range(min=-360, max=360, step=1, name="angle")
angle_var = alt.param(bind=angle_slider, value=0)
size_slider = alt.binding_range(min=0, max=500, step=10, name="size")
size_var = alt.param(bind=size_slider, value=50)
strokeWidth_slider = alt.binding_range(min=0, max=10, step=0.5, name="strokeWidth")
strokeWidth_var = alt.param(bind=strokeWidth_slider, value=2)
alt.Chart(source).mark_point(
shape=shape_var,
angle=angle_var,
size=size_var,
strokeWidth=strokeWidth_var,
).encode(x="Horsepower:Q", y="Miles_per_Gallon:Q").add_params(
shape_var, angle_var, size_var, strokeWidth_var
)
A point
mark definition can contain any standard mark properties
and the following special properties:
Click to show table
Property |
Type |
Description |
---|---|---|
shape |
anyOf(anyOf( |
Shape of the point marks. Supported values include:
Default value: |
size |
anyOf( |
Default size for marks.
Default value:
|
Examples#
Dot Plot#
Mapping a field to either only x
or only y
of point marks creates a dot plot.
import altair as alt
from vega_datasets import data
source = data.movies()
alt.Chart(source).mark_point().encode(
x="IMDB_Rating:Q"
)