标签会影响ggplot

Question

我有一个包含两个不同变量的数据集 - 城市和城镇

当我绘制它们并使用stat_smooth添加两条回归线时，图例符号显示不正确（它们显示为两个'a'）：

ggplot(metrics, aes(x=popDensity, y= TPB, color = factor(type))) + geom_point() +theme_minimal() + stat_smooth(method = "lm", se = FALSE) +
  geom_label_repel(aes(label= rownames(metrics)), size=3) +
  theme(axis.title = element_text(family = "Trebuchet MS", color="#666666", face="bold", size=12)) +
  labs(x = expression(paste( "density ", km^{2})), y = expression(paste("rating[![enter image description here][1]][1]")))+
  theme(legend.position="top", legend.direction="horizontal") 

结果如下：

然而，当我删除geom_label_repel函数时，我会得到我需要的图例符号 - 但当然标签不会出现。

ggplot(metrics, aes(x=popDensity, y= TPB, color = factor(type))) + geom_point() +theme_minimal() + stat_smooth(method = "lm", se = FALSE) +
  #geom_label_repel(aes(label= rownames(metrics)), size=3) +
  theme(axis.title = element_text(family = "Trebuchet MS", color="#666666", face="bold", size=12)) +
  labs(x = expression(paste( "density ", km^{2})), y = expression(paste("rating")))+
  theme(legend.position="top", legend.direction="horizontal")

为什么会发生这种情况，是否有针对此问题的已知解决方法？另外，有没有办法手动更改图例标题的标题？我尝试过使用+ theme(legend.title = "title"）但收到错误：

Error in (function (el, elname)  : 
  Element legend.title must be a element_text object.

样本数据：

> dput(metrics)
structure(list(popDensity = c(4308, 27812, 4447, 5334, 4662, 
2890, 24623, 5847, 1689, 481, 4100), TPB = c(1, 0.5, 1, 1.3, 
0.8, 4, 0.2, 0.7, 5, 4, 2), type = c("City", "City", "City", 
"City", "City", "City", "Town", "Town", "Town", "Town", "Town"
)), .Names = c("popDensity", "TPB", "type"), row.names = c("City1", 
"City2", "City3", "City4", "City5", "City6", "Town1", "Town2", 
"Town3", "Town4", "Town5"), class = "data.frame")

Answer 1

在show.legend = FALSE来电中添加geom_label_repel。 a's似乎是标签的标准图例，它会覆盖使用相同颜色的geom_point。