Question

我正在绘制美国地图，显示每个州的餐馆数量，但没有得到正确的图例。每个州的颜色取决于该州的餐馆范围。此代码完全可重现。

library(ggplot2)

windowsFonts(Arial=windowsFont("TT Arial"))

colorsnew <- c("#C6D7A9","#9DAED9","#C6D7A9","#4A77BB","#9DAED9","#9DAED9","#C7C6C5","#C7C6C5","#4A77BB","#7aad42","#C7C6C5",
  "#4A77BB","#9DAED9","#C6D7A9","#C6D7A9","#C6D7A9","#C6D7A9","#C7C6C5","#9DAED9","#7aad42","#7aad42","#9DAED9","#C6D7A9","#9DAED9",
  "#C7C6C5","#C7C6C5","#C6D7A9","#C7C6C5","#7aad42","#C7C6C5","#4A77BB","#7aad42","#C7C6C5","#7aad42","#C6D7A9","#9DAED9","#4A77BB",
  "#C7C6C5","#9DAED9","#C7C6C5","#9DAED9","#4A77BB","#C6D7A9","#C7C6C5","#9DAED9","#9DAED9","#C7C6C5","#9DAED9","#C7C6C5")
color_legend <- c("0-5000", "5000-10000","10000-20000","20000-30000","30000+")

usa_map <- map_data("state")
plotObj <- ggplot(usa_map, aes(x=long,y=lat,group=group))
plotObj <- plotObj  + geom_polygon(data=usa_map, aes(x=long,y=lat,group=group,fill=region), colour ="white")

plotObj <- plotObj +  scale_fill_manual(values=as.character(colorsnew), label=color_legend)
plotObj <- plotObj +  theme(axis.line=element_blank(),axis.text.x=element_blank(),
                            axis.text.y=element_blank(),axis.ticks=element_blank(),
                            axis.title.x=element_blank(),
                            axis.title.y=element_blank(),
                            legend.text = element_text(family = "Arial"), legend.position = "top",
                            legend.title = element_text(family = "Arial", size = rel(1)),
                            strip.text = element_text(family = "Arial"),
                            panel.background=element_blank(),panel.border=element_blank(),panel.grid.major=element_blank(),
                            panel.grid.minor=element_blank(),plot.background=element_blank())
plotObj <- plotObj + labs(title="Distribution of Restaurants across states in U.S. and Canada")

print(plotObj)

我的问题是图例应该根据color_legend向量显示我可以标记的每种颜色。但是，当我设置legend.position = "top"时，它会显示所有49个州的颜色。如何设置图例，使每种颜色只显示一次适当的标签？我尝试过使用geom_map，但它给了我奇怪的错误。谢谢！

Answer 1

您可以手动设置填充颜色的标签：

plotObj <- plotObj +  scale_fill_manual(
                              values=as.character(unique(colorsnew),
                              labels=color_legend
                                        )

我无法在你的场景中测试它，所以我不确定它是否有效。我假设你还必须设置legend.position =“top”或者将这一点评论出来。

编辑：您的图例仅显示前5个状态，因为您只为scale_fill_manual提供了5个标签。在你提供整个列map.df $ colors_new之前我错过了你的例子，我假设它是49个值，所以缺少44个值。

要解决此问题，请尝试在您的向量周围添加唯一值（请参见上文）。这会将列减少到5个单色值。请注意颜色的顺序是正确的。或者，您只需按正确的顺序构建一个包含5个颜色值的矢量。

colorsnew <- c("#C6D7A9","#9DAED9","#4A77BB","#C7C6C5","#7aad42")

我希望这次有效。

地图传说不对劲

1 个答案: