@mdsumnerのはるかに優れたソリューションを補完するのと同じように、ライブラリncdf
のみを使用してこれを行う方法があります。
library(ncdf)
f <- open.ncdf("LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040101.nc")
A <- get.var.ncdf(nf,"soil_moisture_c")
必要なのは、コヒーレントなx軸とy軸を持つために寸法を見つけることだけです。NetCDFオブジェクトのディメンションを見ると、次のように表示されます。
str(f$dim)
List of 2
$ Longitude:List of 8
..$ name : chr "Longitude"
..$ len : int 1440
..$ unlim : logi FALSE
..$ id : int 1
..$ dimvarid : num 2
..$ units : chr "degrees_east"
..$ vals : num [1:1440(1d)] -180 -180 -179 -179 -179 ...
..$ create_dimvar: logi TRUE
..- attr(*, "class")= chr "dim.ncdf"
$ Latitude :List of 8
..$ name : chr "Latitude"
..$ len : int 720
..$ unlim : logi FALSE
..$ id : int 2
..$ dimvarid : num 1
..$ units : chr "degrees_north"
..$ vals : num [1:720(1d)] 89.9 89.6 89.4 89.1 88.9 ...
..$ create_dimvar: logi TRUE
..- attr(*, "class")= chr "dim.ncdf"
したがって、寸法は次のとおりです。
f$dim$Longitude$vals -> Longitude
f$dim$Latitude$vals -> Latitude
Latitude
これで、逆ではなく90から-90になります。これにより、次のimage
ようになります。
Latitude <- rev(Latitude)
A <- A[nrow(A):1,]
最後に、お気づきのとおり、オブジェクトAのxとyが反転しているため、転置する必要があります。NA値は、何らかの理由で値で表されます-32767
。
A[A==-32767] <- NA
A <- t(A)
そして最後にプロット:
image(Longitude, Latitude, A)
library(maptools)
data(wrld_simpl)
plot(wrld_simpl, add = TRUE)
編集: 31個のファイルでこれを行うには、ファイル名のベクトルとそれらを保存したディレクトリを呼び出しますncfiles
(yourpath
簡単にするために、変数は常に呼び出されsoil_moisture_c
、NAは常に呼び出されると仮定します-32767
):
ncfiles
[1] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040101.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040102.nc"
[3] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040103.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040104.nc"
[5] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040105.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040106.nc"
[7] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040107.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040108.nc"
[9] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040109.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040110.nc"
[11] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040111.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040112.nc"
[13] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040113.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040114.nc"
[15] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040115.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040116.nc"
[17] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040117.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040118.nc"
[19] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040119.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040120.nc"
[21] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040121.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040122.nc"
[23] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040123.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040124.nc"
[25] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040125.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040126.nc"
[27] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040127.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040128.nc"
[29] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040129.nc" "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040130.nc"
[31] "LPRM-AMSR_E_L3_D_SOILM3_V002-20120520T173800Z_20040131.nc"
yourpath
[1] "C:\\Users"
library(ncdf)
library(maptools)
data(wrld_simpl)
for(i in 1:length(ncfiles)){
f <- open.ncdf(paste(yourpath,ncfiles[i], sep="\\"))
A <- get.var.ncdf(f,"soil_moisture_c")
f$dim$Longitude$vals -> Longitude
f$dim$Latitude$vals -> Latitude
Latitude <- rev(Latitude)
A <- A[nrow(A):1,]
A[A==-32767] <- NA
A <- t(A)
close.ncdf(f) # this is the important part
png(paste(gsub("\\.nc","",ncfiles[i]), "\\.png", sep="")) # or any other device such as pdf, jpg...
image(Longitude, Latitude, A)
plot(wrld_simpl, add = TRUE)
dev.off()
}