我如何应用渐变填充到ggplot2中的geom_rect对象? [英] How can I apply a gradient fill to a geom_rect object in ggplot2?
问题描述
我正在使用ggplot2构建一个时间序列折线图,该图利用geom_rect对象来突出显示特定的时间序列事件。
出于纯粹的美学原因,我我对将渐变应用到geom_rect对象感兴趣,因此随着y的增加它渐变为白/透明。
我已经阅读了其他的答案,有人建议 geom_tile 或geom_raster可能会提供一个解决方案。我对此没有任何好运...对我来说geom_rect似乎是一个明显的选择,因为我可以指定时间序列的开始和结束作为边界。但是,我希望我可以被证明是错误的!如果有人有任何指导,将非常感激。到目前为止,我的尝试是:
##读数据
file =Data.csv
timeSeries< - read.csv(file,header = TRUE)
## CONVERT DATA TO DATE CLASS
timeSeries $ Date< - as.Date( timeSeries $ Date,%d /%m /%y)
timeSeries $ Date< - as.Date(format(timeSeries $ Date,19%y-%m-%d))
$ b $ ## SET GEOM_RECT数据帧
事件< -c(Event1,Event2,Event3)
startDate< - c(15 / 06/15,12/07/17,6/09/18)
finishDate< - c(9/01/16,18/11/17,5 / 11/18)
日期< - cbind(event,startDate,finishDate)
日期< - as.data.frame(日期,rownames = NULL,stringsAsFactors = FALSE)
日期$ startDate< - as.Date(日期$ startDate,%d /%m /%y)
日期$ startDate< - as.Date(格式$ startDate,19%y-%m-%d))
日期$ finishDate< - as.Date(日期$ finishDate,%d /%m /%y)
日期$ finishDate< - as.Date(格式(日期$ finishDate,19%y-%m-%d))
##使用GGPLOT
plot <-ggplot(timeSeries)+
geom_rect(data = dates,aes(xmin = startDate,xmax = finishDate,ymin = 0,ymax = 25),fill =blue, alpha = 0.4)+
geom_line(aes(x = Date,y = Event))+
scale_x_date(labels = date_format(19%y))+
ggtitle() +
xlab(Time Series)+
ylab(Number)+
theme_minimal()
plot
上面的代码应该产生这个图。您可以从此处下载数据。
这里是我对@ baptiste想法的实现。看起来很花哨!
ggplot_grad_rects < - function(n,ymin,ymax){
y_steps < - seq从= ymin到= ymax,length.out = n + 1)
alpha_steps <-seq(从= 0.5,到= 0,length.out = n)
rect_grad < - 数据。 frame(ymin = y_steps [ - (n + 1)],
ymax = y_steps [-1],
alpha = alpha_steps)
rect_total< - merge(dates,rect_grad)
ggplot(timeSeries)+
geom_rect(data = rect_total,
aes(xmin = startDate,xmax = finishDate,
ymin = ymin,ymax = ymax,
alpha = alpha ),fill =blue)+
guides(alpha = FALSE)
}
ggplot_grad_rects(100,0,25)+
geom_line(aes(x = Date,y = Event))+
scale_x_date(labels = date_format(19%y))+
ggtitle()+
xlab(Time Series)+
ylab(Number)+
theme_minimal()
I'm in the midst of building a time series line chart using ggplot2 that utilises geom_rect objects to highlight a particular time series event.
For purely aesthetic reasons I'm interested in applying a gradient to the geom_rect object so that it fades to white/transparent as y increases.
I have read other answers where it has been suggested that geom_tile or geom_raster may offer a solution. I've had no luck with this... to me geom_rect seems to be the obvious choice since I can specify the beginning and end of the time series as boundaries. However, I'm hoping that I can be proven wrong! If anyone has any guidance, it would be very much appreciated. My attempt thus far is:
## READ DATA
file = "Data.csv"
timeSeries <- read.csv(file, header=TRUE)
## CONVERT DATA TO DATE CLASS
timeSeries$Date <- as.Date(timeSeries$Date, "%d/%m/%y")
timeSeries$Date <- as.Date(format(timeSeries$Date, "19%y-%m-%d"))
## SET GEOM_RECT DATA FRAME
event <- c("Event1", "Event2", "Event3")
startDate <- c("15/06/15", "12/07/17", "6/09/18")
finishDate <- c("9/01/16", "18/11/17", "5/11/18")
dates <- cbind(event, startDate, finishDate)
dates <- as.data.frame(dates, rownames=NULL, stringsAsFactors=FALSE)
dates$startDate <- as.Date(dates$startDate, "%d/%m/%y")
dates$startDate <- as.Date(format(dates$startDate, "19%y-%m-%d"))
dates$finishDate <- as.Date(dates$finishDate, "%d/%m/%y")
dates$finishDate <- as.Date(format(dates$finishDate, "19%y-%m-%d"))
## PLOT USING GGPLOT
plot <- ggplot(timeSeries) +
geom_rect(data=dates, aes(xmin=startDate, xmax=finishDate, ymin=0, ymax=25), fill="blue", alpha=0.4) +
geom_line(aes(x=Date, y=Event)) +
scale_x_date(labels=date_format("19%y")) +
ggtitle("") +
xlab("Time Series") +
ylab("Number") +
theme_minimal()
plot
The code above should produce this plot. Data can be downloaded from here.
Here's my implementation of @baptiste's idea. Looks fancy!
ggplot_grad_rects <- function(n, ymin, ymax) {
y_steps <- seq(from = ymin, to = ymax, length.out = n + 1)
alpha_steps <- seq(from = 0.5, to = 0, length.out = n)
rect_grad <- data.frame(ymin = y_steps[-(n + 1)],
ymax = y_steps[-1],
alpha = alpha_steps)
rect_total <- merge(dates, rect_grad)
ggplot(timeSeries) +
geom_rect(data=rect_total,
aes(xmin=startDate, xmax=finishDate,
ymin=ymin, ymax=ymax,
alpha=alpha), fill="blue") +
guides(alpha = FALSE)
}
ggplot_grad_rects(100, 0, 25) +
geom_line(aes(x=Date, y=Event)) +
scale_x_date(labels=date_format("19%y")) +
ggtitle("") +
xlab("Time Series") +
ylab("Number") +
theme_minimal()
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