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所以我正在为一些数据创建一个热图，并让它显示按小时和星期几聚合的车辆数量。但是，当我制作地图时，图例似乎不起作用，因此，瓷砖不会上升到“最深的红色阴影”。有谁知道发生了什么？谢谢：

Hourplus <- c(Hour, Hour, Hour, Hour, Hour, Hour, Hour, Hour)
facetgrid <- data.frame(DayofWeek, Totals5, Totals6, Totals3, Totals4, Totals1, Totals2, Totals7, Totals8)
names(facetgrid) <- c("DayofWeek", "Marine Dr NB", "Marine Dr SB", "Carman NB", "Carman SB", "Glisan NB", "Glisan SB", "Stafford NB", "Stafford SB")


facetgrid <- melt(facetgrid)
facetgrid$DayofWeek <- factor(facetgrid$DayofWeek, levels=c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"))
facetgrid
levels(facetgrid$DayofWeek) <- c("M","Tu","W","Th","F","Sa","Su")
gg <- ggplot(facetgrid, aes(x=Hourplus, y=DayofWeek, fill=value)) + geom_tile(color="white", size=0.1) + facet_wrap(~variable, ncol = 2, scales='free')
gg <- gg + coord_equal()
gg <- gg + labs(x=NULL, y=NULL, title ="May 2017: Volume of Vehicles Greater than 20ft in Length")
gg <- gg + theme_tufte()
gg <- gg + theme(plot.title=element_text(hjust=0.5))
gg <- gg + theme(axis.ticks=element_blank())
gg <- gg + theme(axis.text=element_text(size=7))
gg <- gg + theme(legend.title=element_text(size=8))
gg <- gg + theme(legend.text=element_text(size=6))
gg <- gg + scale_fill_gradient(low = "white",high = "red", name="Volume")
gg <- gg + scale_x_continuous(breaks=seq(0,24,4), limits=c(0,25))
ggsave("8stationsvol.png", height =8, width = 12)

这就是地图现在的样子（没有一个图块是最深的红色） 图

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1 回答 1

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Ggplot 确实为大多数连续性质的尺度增加了“摆动”空间，就像 X 和 Y 轴一样。要设置严格（或自定义）限制，请使用 scale_fill_gradient 中的函数“limits”。在你的情况下，给它一个带有下限和上限的向量。

gg + scale_fill_gradient(low = "white",
      high = "red",
      name="Volume",
      limits = c(min(facetgrid$value), max(facetgrid$value)))
于 2017-08-04T02:03:44.327 回答