ggplot系数图scale_fill_manual图例线条颜色设置失效问题

你遇到的问题核心是：geom_pointrange的误差线和点的轮廓颜色由color参数控制，而你仅映射了fill（该参数仅控制点的填充色，默认点为空心样式，所以填充色无法显示），因此图例里的线条（对应误差线）仍为默认黑色。

两种修正方案 #

方案1：直接用color映射模型分组（简洁版）

把aes里的fill替换为color，同时将scale_fill_manual改为scale_color_manual，这样点和误差线都会按模型分组显示对应颜色：

# packages
library(ggplot2)
library(broom)

# list models
models <- list(
  "No controls" = lm(mpg ~ wt, data = mtcars),
  "Controls" = lm(mpg ~ wt + hp + qsec, data = mtcars)
)

# define variables
cm <- c('wt' = 'Weight',
        'hp' = 'Horsepower',
        'qsec' = 'Quarter Mile Time')

# combine all coefficients from models
coef_data <- data.frame()
for (model_name in names(models)) {
  model <- models[[model_name]]
  tidy_df <- tidy(model)
  tidy_df$model <- model_name
  coef_data <- rbind(coef_data, tidy_df)
}

# filter to only show cm variables
coef_data <- coef_data[coef_data$term %in% names(cm), ]

# create levels
coef_data$model <- factor(coef_data$model, levels = c("Controls", "No controls"))

# 修正后的ggplot代码
p <- ggplot(coef_data, aes(x = term, y = estimate, ymin = estimate - 1.96 * std.error, ymax = estimate + 1.96 * std.error, color = model)) +
  geom_pointrange(position = position_dodge(width = 0.7)) +
  geom_hline(yintercept = 0, linetype = "dashed") +
  scale_color_manual(values = c("Controls" = "red", "No controls" = "blue")) +
  theme_minimal() +
  labs(x = "Variable", y = "Estimate", color = "Model")

p

方案2：保留填充色+自定义实心点（进阶版）

如果想要点显示填充色，同时误差线匹配对应颜色，可以给geom_pointrange指定带填充的形状（如shape=21），同时映射fill和color：

# 修正后的ggplot代码
p <- ggplot(coef_data, aes(x = term, y = estimate, ymin = estimate - 1.96 * std.error, ymax = estimate + 1.96 * std.error, fill = model, color = model)) +
  geom_pointrange(position = position_dodge(width = 0.7), shape = 21, size = 1) +
  geom_hline(yintercept = 0, linetype = "dashed") +
  scale_fill_manual(values = c("Controls" = "red", "No controls" = "blue")) +
  scale_color_manual(values = c("Controls" = "red", "No controls" = "blue")) +
  theme_minimal() +
  labs(x = "Variable", y = "Estimate", fill = "Model", color = "Model")

# 合并重复图例
p + guides(color = guide_legend(title = "Model"), fill = guide_legend(title = "Model"))

关键说明 #

• geom_pointrange的误差线、点轮廓受color控制；点的内部填充仅在使用带填充的形状（如shape21-25）时，由fill参数生效。
• 方案1适合只需要统一颜色的场景，方案2适合需要区分点填充与轮廓的场景。

内容的提问来源于stack exchange，提问作者hy9fesh