我最近开始在R中使用netcdf。示例数据在这里:

http://www.earthstat.org/data-download/> 175种作物的收获面积和单产>单个作物>大 bean _HarvAreaYield2000_NetCDF

在此文件夹中,有一个名为soybean_AreaYieldProduction.nc的netcdf文件。

这就是我打开netcdf的方式

 library(ncdf4)

 dat <- nc_open("soybean_AreaYieldProduction.nc")
 print(soy)

1 variables (excluding dimension variables):
    float soybeanData[longitude,latitude,level,time]
LayerDescriptions: struct(5).Data(:,:,1/2/3/4/5/6) to access data layer: 1=Harvested Area fraction, 2=Yield 3=Harvested Area data quality, 4=Yield data quality, 5=Harvested Area in hectares, 6= Production
        Units: Harvested Area Fraction(1)=percent of gridcell that was harvested, Yield(2)=metric tons per hectare, Harvested Area Hectares(5)=total hectares harvested per gridcell, Production(6)=Metric Tons
        DataQuality: In levels 3 and 4, a value of 1 = county; .75 = state; .5 = interpolated from within 2 degrees lat/long; .25 = country; 0 = missing.
4 dimensions:
        longitude  Size:4320
        units: longitude
        latitude  Size:2160
        units: latitude
        level  Size:6
        time  Size:1

我想绘制每个级别,但不知道如何为每个级别提取数据。

这是我提取lon和lat数据的方式:
lon <- ncvar_get(dat,"longitude") # extract long

lat <- ncvar_get(dat,"latitude") # extract lat

但是,如何提取个人水平?
level.1 <- ncvar_get(dat, ????)

最终目的是可视化每个级别
我想使用以下命令进行可视化:
image(lon,lat, level)

最佳答案

使用raster包可能是最简单的:

library(raster)
r1 <- raster("soybean_AreaYieldProduction.nc", level=1)
r2 <- raster("soybean_AreaYieldProduction.nc", level=2)

plot(r1)
image(r1)
s <- stack(r1, r2)
plot(s)

其他绘图方法
spplot(s)

library(rasterVis)
levelplot(r1)
levelplot(s)

并查看CRAN上的其他映射包

关于r - 用R中的级别绘制netcdf文件,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/47538582/

10-12 19:59