如果 altair 中有多個 y 軸，如何增加標簽間距和刻度間距？

Question

我正在嘗試增加繪圖的易讀性，因為 y 軸標簽（左側）已經重疊並調整它們之間的刻度范圍和間隔。請幫助我這樣做多軸組合圖

import altair as alt
from vega_datasets import data
source = data.seattle_weather()
base = alt.Chart(source).encode( alt.X('month(date):T', axis=alt.Axis(title=None)))
area = base.mark_area(opacity=0.3, color='#57A44C').encode(
    alt.Y('average(temp_max)',
          axis=alt.Axis(title='Avg. Temperature (°C)', titleColor='#57A44C')),
    alt.Y2('average(temp_min)'))

line = base.mark_line(stroke='#5276A7', interpolate='monotone').encode(
    alt.Y('average(precipitation)',
          axis=alt.Axis(title='Precipitation (inches)', titleColor='#5276A7')))

line2 = base.mark_line(stroke='#5276A7', interpolate='monotone').encode(
    alt.Y('average(wind)',
          axis=alt.Axis(title='wind', titleColor='#5276A7')))

alt.layer(area, line,line2).resolve_scale(y = 'independent').configure_axisY()

Answer 1

在技​​術上可以使用offset參數移動第三個 y 軸：

import altair as alt
from vega_datasets import data


source = data.seattle_weather()
base = alt.Chart(source).encode( alt.X('month(date):T', axis=alt.Axis(title=None)))
area = base.mark_area(opacity=0.3, color='#57A44C').encode(
    alt.Y('average(temp_max)',
          axis=alt.Axis(title='Avg. Temperature (°C)', titleColor='#57A44C')),
    alt.Y2('average(temp_min)'))

line = base.mark_line(stroke='#5276A7', interpolate='monotone').encode(
    alt.Y('average(precipitation)',
          axis=alt.Axis(title='Precipitation (inches)', titleColor='#5276A7')))

line2 = base.mark_line(stroke='coral', interpolate='monotone').encode(
    alt.Y('average(wind)',
          axis=alt.Axis(title='wind', titleColor='coral', offset=60)))

alt.layer(area, line,line2).resolve_scale(y = 'independent').configure_axisY()

但是，我會考慮制作單獨的圖，因為閱讀具有多個 y 軸的圖表可能會變得困難。 如果垂直堆疊圖，仍然很容易比較三種不同測量值的趨勢：

base = alt.Chart(source, height=150).encode(alt.X('month(date):T', axis=None))
area = base.mark_area(opacity=0.3, color='#57A44C').encode(
    alt.Y('average(temp_max)',
          axis=alt.Axis(title='Avg. Temperature (°C)', titleColor='#57A44C')),
    alt.Y2('average(temp_min)'))

line = base.mark_line(stroke='#5276A7', interpolate='monotone').encode(
    alt.Y('average(precipitation)',
          axis=alt.Axis(title='Precipitation (inches)', titleColor='#5276A7')))

line2 = base.mark_line(stroke='coral', interpolate='monotone').encode(
    alt.Y('average(wind)',
          axis=alt.Axis(title='wind', titleColor='coral')),
    alt.X('month(date):T')
)

alt.vconcat(area, line, line2, spacing=0).resolve_scale(x='shared')