我想绘制一堆栅格图像,并创建了一个代码来调整每个图像的间断点并通过for循环绘制它们。但是,我得到了一个有问题的颜色比例尺条,而我的努力并没有有效地解决这个问题。例如:
我有从0到11,000的降水量...但大部分数据在0到5,000之间...只有很少的数据高达11,000。因此,我需要更改间断点以捕捉这种变化...在我有更多数据的地方使用更多的间断点。
然后我为此创建了一个间断点对象。
但是当我绘制栅格图像时,比例尺颜色条变得非常糟糕,非常混乱...
但是这并不起作用,因为地图中的颜色与数字并不真正匹配...看看每个地图中6.000的颜色...它们是不同的。
我有从0到11,000的降水量...但大部分数据在0到5,000之间...只有很少的数据高达11,000。因此,我需要更改间断点以捕捉这种变化...在我有更多数据的地方使用更多的间断点。
然后我为此创建了一个间断点对象。
但是当我绘制栅格图像时,比例尺颜色条变得非常糟糕,非常混乱...
#get predictors (These are a way lighter version of mine)
predictors_full<-getData('worldclim', var='bio', res=10)
predic_legends<-c(
"Annual Mean Temperature [°C*10]",
"Mean Diurnal Range [°C]",
"Isothermality",
"Temperature Seasonality [standard deviation]",
"Max Temperature of Warmest Month [°C*10]",
"Min Temperature of Coldest Month [°C*10]",
"Temperature Annual Range [°C*10]",
"Mean Temperature of Wettest Quarter [°C*10]",
"Mean Temperature of Driest Quarter [°C*10]",
"Mean Temperature of Warmest Quarter [°C*10]",
"Mean Temperature of Coldest Quarter [°C*10]",
"Annual Precipitation [mm/year]",
"Precipitation of Wettest Month [mm/month]",
"Precipitation of Driest Month [mm/month]",
"Precipitation Seasonality [coefficient of variation]",
"Precipitation of Wettest Quarter [mm/quarter]",
"Precipitation of Driest Quarter [mm/quarter]",
"Precipitation of Warmest Quarter [mm/quarter]",
"Precipitation of Coldest Quarter [mm/quarter]",
)
# Crop rasters and rename
xmin=-120; xmax=-35; ymin=-60; ymax=35
limits <- c(xmin, xmax, ymin, ymax)
predictors <- crop(predictors_full,limits)
predictor_names<-c("mT_annual","mT_dayn_rg","Isotherm","T_season",
"maxT_warm_M","minT_cold_M","rT_annual","mT_wet_Q","mT_dry_Q",
"mT_warm_Q","mT_cold_Q","P_annual","P_wet_M","P_dry_M","P_season",
"P_wet_Q","P_dry_Q","P_warm_Q","P_cold_Q")
names(predictors)<-predictor_names
#Set a palette
Blues_up<-c('#fff7fb','#ece7f2','#d0d1e6','#a6bddb','#74a9cf','#3690c0','#0570b0','#045a8d','#023858','#233159')
colfunc_blues<-colorRampPalette(Blues_up)
#Create a loop to plot all my Predictor rasters
for (i in 1:19) {
#save a figure
png(file=paste0(predictor_names[[i]],".png"),units="in", width=12, height=8.5, res=300)
#Define a plot area
par(mar = c(2,2, 3, 3), mfrow = c(1,1))
#extract values from rasters
vmax<- maxValue(predictors[[i]])
vmin<-minValue(predictors[[i]])
vmedn=(maxValue(predictors[[i]])-minValue(predictors[[i]]))/2
#breaks
break1<-c((seq(from=vmin,to= vmedn, length.out = 40)),(seq(from=(vmedn+(vmedn/5)),to=vmax,length.out = 5)))
#plot without the legend because the legend would come out with really messy, with too many marks and uneven spaces
plot(predictors[[i]], col =colfunc_blues(45) , breaks=break1, margin=FALSE,
main =predic_legends[i],legend.shrink=1)
dev.off()
}
接着,我编写了另一段代码来设置颜色条的不同断点。
#Plot the raster with no color scale bar
plot(predictors[[i]], col =colfunc_blues(45) , breaks=break1, margin=FALSE,
main =predic_legends[i],legend=FALSE)
#breaks for the color scale
def_breaks = seq(vmax,vmin,length.out=(10))
#plot only the legend
image.plot(predictors_full[[i]], zlim = c(vmin,vmax),
legend.only = TRUE, col = colfunc_greys(30),
axis.args = list(at = def_breaks, labels =def_breaks,cex.axis=0.5))
但是这并不起作用,因为地图中的颜色与数字并不真正匹配...看看每个地图中6.000的颜色...它们是不同的。
有关如何进行操作,你有什么建议吗? 我是R的新手,所以我很难达到我的目标...... 另外,数字中有很多小数位......如何将其更改为2个小数位?
编辑:@jbaums教我使用对数......我喜欢但还不是我寻求的
levelplot(predictors[[12]]+1, col.regions=colorRampPalette(brewer.pal(9, 'Blues')), zscaleLog=TRUE, at=seq(1, 4, len=100), margin=FALSE)
library(rasterVis); library(RColorBrewer); levelplot(predictors[[12]]+1, col.regions=colorRampPalette(brewer.pal(9, 'Blues')), zscaleLog=TRUE, at=seq(1, 4, len=100), margin=FALSE)
- jbaums