ylim在打印输出（WindR）中约束数据，但不约束轴

我正在学习WindR（）的教程，并按照说明进行操作，但是当涉及到在地图上绘制数据时，纬度界限要比数据范围大得多。数据范围从20到60纬度，而地图输出的范围要大得多

将ylim参数调整为plot（）不会改变数据显示：

# Finally, we can transform this data into a raster layer  
rmax <- rasterFromXYZ(maxw)  
acol <- colorRampPalette(c("white", "blue", "darkblue"))  
plot(rmax, col=acol(1000), main= "Maximum wind speed reported",  
     xlab="Longitude", ylab="Lattitude", ylim=c(20,60))  
#add world map lines
lines(getMap(resolution = "high"), lwd=2)

最后，我们可以将这些数据转换为光栅图层 rmax

library(rWind)  
library(lubridate)  
library(dplyr)  
library(rworldmap)  

# Here, we use ymd_hms from lubridate package to create a sequence of dates  

dt <- seq(ymd_hms(paste(2018,6,1,12,00,00, sep="-")),  
          ymd_hms(paste(2018,6,30,12,00,00, sep="-")),by="1 days")  

# Now we can use wind.dl_2 with this sequence of dates. Have into account  
# that it could take a while, they are 30 datasets and it's a big area.   

ww <- wind.dl_2(dt,-85,5,20,60)  

# After tidy our wind data, we can use dplyr utilities to easily  
# obtain several metrics from our wind data. Notice that wind average  
# is a special case, and it will be discussed later  
t_ww <- tidy(ww)  


g_ww <- t_ww %>% group_by(lat, lon)  

# Now, we select only the maximum speed values for each coordinate  
max_ww <- g_ww %>% summarise(speed = max(speed))  
maxw <- cbind(max_ww$lon, max_ww$lat, max_ww$speed)  
head(maxw)

# Finally, we can transform this data into a raster layer  
rmax <- rasterFromXYZ(maxw)  
acol <- colorRampPalette(c("white", "blue", "darkblue"))  
plot(rmax, col=acol(1000), main= "Maximum wind speed reported",  
     xlab="Longitude", ylab="Lattitude", ylim=c(20,60))  
#add world map lines
lines(getMap(resolution = "high"), lwd=2)