NetCDF到Raster Brick“无法为'ncdf4'找到功能'brick'的继承方法"

问题描述

光栅包确实很简单，也使用ncdf4加载到ECMWF Era-Interim Netcdf文件中.

Really simple problem with the raster package, also using ncdf4 to load in an ECMWF Era-Interim Netcdf file.

只需这样做:

a <- nc_open("SSTs.nc")
B <- brick(a, varname="sst")

返回此:

    Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function ‘brick’ for signature ‘"ncdf4"’

该文件只是1个月(2016年1月)在全球范围内的SST数据.当我将其转换为数组时(即提取尺寸/变量，并将时间转换为UTC，将其推入数组中)，我没有得到相同的错误，但是栅格数据包说它直接支持.nc文件(太长了因为它们是cf-1兼容的，所以是Era-Interim .nc的)

The file is just SST data over the whole globe, for 1 month (Jan2016). When I convert it into an array (i.e. extract dimensions/variable, and convert time to UTC, shove it into an array) I don't get the same error, but the raster package says it supports .nc files straight in (so long as they're cf-1 compatible, which Era-Interim .nc's are)

非常感谢任何帮助，已经尝试了许多Netcdf文件(也包括非Era Interim).

Any help much appreciated, have tried this with many Netcdf files (non-Era Interim too).

推荐答案

感谢 Renaud Lancelot ，谁会清楚地给出源代码.我已经修改了他的代码以适合您的数据

thank Renaud Lancelot, who give clearly source code. I have modified his code to fit with your data

 # load package
 library(sp)
 library(raster)
 library(ncdf4)

 # read ncdf file
 nc<-nc_open('D:/SSTs.nc')

 # extract variable name, size and dimension
 v <- nc$var[[1]]
 size <- v$varsize
 dims <- v$ndims
 nt <- size[dims]              # length of time dimension
 lat <- nc$dim$latitude$vals   # latitude position
 lon <- nc$dim$longitude$vals  # longitude position

 # read sst variable
 r<-list()
 for (i in 1:nt) {
   start <- rep(1,dims)     # begin with start=(1,1,...,1)
   start[dims] <- i             # change to start=(1,1,...,i) to read    timestep i
   count <- size                # begin with count=(nx,ny,...,nt), reads entire var
   count[dims] <- 1             # change to count=(nx,ny,...,1) to read 1 tstep

   dt<-ncvar_get(nc, varid = 'sst', start = start, count = count)

   # convert to raster
   r[i]<-raster(dt)
 }

 # create layer stack with time dimension
 r<-stack(r)

 # transpose the raster to have correct orientation
 rt<-t(r)
 extent(rt)<-extent(c(range(lon), range(lat)))

 # plot the result
 spplot(rt)

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