如何在代码中保存R中的图形

Question

我正在绘制观察到的和建模场的2个概率密度函数。 我在下面有此代码：

# Import libraries
library("stringr")
library(ggplot2)

#EXTENDED Observations with reanalysis obervatory 085320
# load in the text files and convert to dataframe
directory = '/Users/jacob/Desktop/Master Meteorologia/PE/Datos/Lisboa/wind/00_Observed/Extended/Observed-Wind-Lisboa_Extended/'
filename = '085320_Wind_Extended.txt'

directory2 = '/Users/jacob/Desktop/Master Meteorologia/PE/Datos/Lisboa/wind/MPI-ESM-MR/Historical/'
filename2 = 'Wind_MPI-ESM-MR_Historical_085320.txt'

extFile = read.delim(str_c(directory,filename), header = FALSE, col.names=c("Year", "Month", "Day", "WindMagn"))
histFile = read.delim(str_c(directory2,filename2), header = FALSE, col.names=c("Year", "Month", "Day", "WindMagn"))

# Extract vecto==wind from both cases
windMagnExt = extFile$WindMagn
windMagnHist = histFile$WindMagn


### PDF observed and modelled
d= density(windMagnExt)
e= density(windMagnHist)
#png('/Users/jacob/Desktop/Master Meteorologia/PE/Figures/windMagnObsHist_PDF.png', width = 1000, height=1000, units='px' ,res=700, pointsize = 12)
plot(d, main="PDF of observed and modelled wind for Obs. 085320", col="red")
lines(e, col="blue" )
legend("topright", legend=c("Observed", "Modelled"),
       col=c("red", "blue"), lty=1:2, cex=0.8)
grid()
#dev.off()

它给了我这种类型的图：

​

1. 在传说中，建模的字段是一条虚线，而不是。我该如何更改。

2. 我尝试取消2行PNG（）和dev.off（）以将图保存在代码中，而不必在rstudio中使用导出按钮。我按照以下方式进行：

### PDF observed and modelled
d= density(windMagnExt)
e= density(windMagnHist)
png('/Users/jacob/Desktop/Master Meteorologia/PE/Figures/windMagnObsHist_PDF.png', width = 15, height=10, units='px' ,res=700, pointsize = 12)
plot(d, main="PDF of observed and modelled wind for Obs. 085320", col="red")
lines(e, col="blue" )
legend("topright", legend=c("Observed", "Modelled"),
       col=c("red", "blue"), lty=1:2, cex=0.8)
grid()
dev.off()

但是它给了我这个错误。我之前曾尝试过使用此此数字保存其他数字，但现在它告诉我，数字保证金太大

编辑：

基于DJ的评论，我在下面尝试运行png（），而无需运行png（）参数：

### PDF observed and modelled
d= density(windMagnExt)
e= density(windMagnHist)
png('/Users/jacob/Desktop/Master Meteorologia/PE/Figures/windMagnObsHist_PDF.png', res=300)
plot(d, main="PDF of observed and modeled wind for Obs. 085320", col="red", xlab='Wind speed (m/s)')
lines(e, col="blue" )
legend("topright", legend=c("Observed", "Modeled"),
       col=c("red", "blue"), lty=1:1, cex=0.8)
grid()
dev.off()

它为我提供了我想要的绘图，但是当添加参数 res = 300 时，我仍然得到与上面相同的错误。

有帮助吗？谢谢！