【R】R语言NC文件读写

#(1)读取NC文件小时数据信息---------

library(ncdf4)

nc <- nc_open('AQI_Grid_2020040708.nc')

print(nc)

PM25 <- ncvar_get( nc = nc, varid = 'PM25')

PM10 <- ncvar_get( nc = nc, varid = 'PM10')

O3 <- ncvar_get( nc = nc, varid = 'O3')

AQI <- ncvar_get( nc = nc, varid = 'AQI')

longitude<-ncvar_get( nc = nc, varid = 'lon')

latidue<-ncvar_get( nc = nc, varid = 'lat')

nc_close( nc )

#(2)将计算完的结果写入新的NC文件-------------------

# Define some straightforward dimensions

lon <- ncdim_def( "lon", "degrees_east", vals=longitude)

lat <- ncdim_def( "lat", "degrees_north", vals=latidue)

time <- ncdim_def( "Time", "24h-48h-72h mean", vals=c(24,48,72))

#Make varables of various dimensionality, for illustration purposes

mv <- -9999 # missing value to use

aq_fcst_PM25<- ncvar_def( name = 'PM25', units = 'ug/m3', dim = list(lon,lat,time), missval = -9999, prec = 'float' )

aq_fcst_PM10<- ncvar_def( name = 'PM10', units = 'ug/m3', dim = list(lon,lat,time), missval = -9999, prec = 'float' )

aq_fcst_O3<- ncvar_def( name = 'O3', units = 'ug/m3', dim = list(lon,lat,time), missval = -9999, prec = 'float' )

aq_fcst_AQI<- ncvar_def( name = 'AQI', units = '1', dim = list(lon,lat,time), missval = -9999, prec = 'float' )

#创建文档

ncnew <- nc_create( filename = 'AQI_GRID_2020040708_024-048-072.nc', vars =list(aq_fcst_PM25,aq_fcst_PM10,aq_fcst_O3,aq_fcst_AQI) )

#写入数据

ncvar_put( nc = ncnew, varid = aq_fcst_PM25, vals = PM25_24_48_72 )

ncvar_put( nc = ncnew, varid = aq_fcst_PM10, vals = PM10_24_48_72 )

ncvar_put( nc = ncnew, varid = aq_fcst_O3, vals = O3_24_48_72 )

ncvar_put( nc = ncnew, varid = aq_fcst_AQI, vals = O3_24_48_72 )

#写入属性

nc_close(ncnew)