如何解决ggplot2中多geom_point图层图例重叠及Faits点样式问题

问题解决思路 #

你的问题核心在于两个geom_point图层同时生成图例导致重叠，且区域汇总点未关联尺寸美学导致图例显示异常。以下是针对性修复：

• 关闭区域点的自动图例，让主数据点（Faits）负责输出color和size图例
• 手动自定义color图例，明确区分主数据点（空心圆）和区域汇总点（实心圆）
• 固化两类点的形状属性，确保显示符合预期

修改后的完整代码 #

library(ggplot2)
library(ggrepel)
library(stringr)

set.seed(123)
data_filtered <- data.frame(
    evolution = runif(15, -10, 10),
    tauxpourmille = runif(15, 0, 100),
    faits = sample(1:100, 15, replace = TRUE),
    Code.région = sample(letters[1:3], 15, replace = TRUE),
    Code.département = sample(LETTERS[1:5], 15, replace = TRUE)
)

evol_tpm_reg_filtered <- data.frame(
    evolution_reg = runif(3, -10, 10),
    tauxpourmille = runif(3, 0, 100),
    Code.région = letters[1:3]
)

x_label <- "Évolution"
y_label <- "Taux pour mille"

region_colors <- c("red", "blue", "green")

ggplot(data_filtered, aes(x = evolution, y = tauxpourmille, size = faits, color = factor(Code.région))) +
    # 主数据点：空心圆，负责输出图例
    geom_point(shape = 1, stroke = 1.3, alpha = 0.6, show.legend = TRUE) +
    geom_text_repel(aes(label = Code.département),
                    family = "sans",
                    box.padding = 3,
                    size = 5,
                    min.segment.length = 0,
                    force = 20,
                    max.overlaps = 50,
                    segment.size = 0.5,
                    show.legend = FALSE) +
    # 区域汇总点：实心圆，关闭自动图例
    geom_point(data = evol_tpm_reg_filtered, aes(x = evolution_reg, y = tauxpourmille, color = factor(Code.région)),
               size = 5, shape = 16, show.legend = FALSE) +
    labs(x = str_wrap(x_label, width = 90),
         y = str_wrap(y_label, width = 35),
         color = "Region",
         size = "Faits") +
    theme_minimal() +
    scale_color_manual(values = region_colors) +
    scale_size_area(max_size = 30,
                    breaks = c(min(data_filtered$faits), median(data_filtered$faits), max(data_filtered$faits)),
                    labels = scales::number_format(accuracy = 1)) +
    # 自定义color图例：明确区分两类点
    guides(
        color = guide_legend(
            override.aes = list(
                shape = c(1, 1, 1),  # 图例中主数据点固定为空心圆
                size = c(5,5,5)      # 统一图例点大小，不受size美学影响
            ),
            title = "Region\n(Faits: 空心圆 | 区域汇总: 实心圆)"
        ),
        size = guide_legend(title = "Faits")
    ) +
    theme(axis.title.x = element_text(family = "sans", margin = margin(t = 15)),
          axis.title.y = element_text(family = "sans", margin = margin(r = 15)),
          axis.text.x = element_text(face = "bold", family = "sans"),
          axis.text.y = element_text(face = "bold", family = "sans"),
          axis.line.x = element_line(size = 1, color = "lightgray"),
          axis.line.y = element_line(size = 1, color = "lightgray"),
          legend.position = "right") +
    expand_limits(x = range(data_filtered$evolution) + c(-0.5, 0.5) * diff(range(data_filtered$evolution)),
                  y = range(data_filtered$tauxpourmille) + c(-0.5, 0.5) * diff(range(data_filtered$tauxpourmille)))

关键修改说明 #

1. 关闭区域点图例：将区域汇总点图层的show.legend设为FALSE，避免重复生成图例元素造成重叠
2. 自定义颜色图例：通过guide_legend()强制图例中的主数据点显示为空心圆，并在标题中补充两类点的区分说明
3. 固化点形状：主数据点保持shape=1（空心圆），区域点保持shape=16（实心圆），确保视觉效果符合需求

内容的提问来源于stack exchange，提问作者NoNameBoyy