"""
Scatter Plot with Rolling Mean
------------------------------
A scatter plot with a rolling mean overlay. In this example a 30 day window
is used to calculate the mean of the maximum temperature around each date.
"""
# category: scatter plots

import altair as alt
from vega_datasets import data

source = data.seattle_weather()

line = (
    alt.Chart(source)
    .mark_line(color="red", size=3)
    .transform_window(rolling_mean="mean(temp_max)", frame=[-15, 15])
    .encode(x="date:T", y="rolling_mean:Q")
)

points = (
    alt.Chart(source)
    .mark_point()
    .encode(x="date:T", y=alt.Y("temp_max:Q", axis=alt.Axis(title="Max Temp")))
)

points + line
