stuck with extracting and converting nc file

Question

i have rainfall file nc and temperature file nc, i do'nt really understand with r, no experience before, so i'm trying this script and get error,

library(ncdf4)
library(data.table)
library(raster)
library(metR)
library(rgdal)


tmax2 <- nc_open("E:/SKRIPSI/prec-tmin-tmax-sumut/tmax2006-2022.nc")
> names(tmax2$var)
[1] "TASMAX"
> names(tmax2$dim)
[1] "NTIME1"      "XAXIS23_301" "YAXIS26_132" "M2"         
> info.file <- GlanceNetCDF(tmaxsumut)
Error in GlanceNetCDF(tmaxsumut) : could not find function "GlanceNetCDF"
> 
> #pemilihan lokasi & waktu
> lat <- 0:4
> lon <- 98:100
> wkt <- seq(from = as.Date("2017-01-01"),
+            to = as.Date("2020-12-31"),
+            by = "days")
> 
> tmax2 <- ReadNetCDF(tmaxsumut, vars="TASMAX",
+                     subset=list(XAXIS23_301=lon, YAXIS26_132= lat, NTIME1=wkt))
Error in ReadNetCDF(tmaxsumut, vars = "TASMAX", subset = list(XAXIS23_301 = lon,  : 
  could not find function "ReadNetCDF"

Answer 1

You are not describing what you want to achieve, making it very difficult to help. Feel free to edit your question to clarify your goals (do not use the comments for that).

I am guessing that you want to extract values from the ncdf file for point (long/lat) locations. If so, similar questions have been asked many times on this site, so you could probably do some more searches.

With standard compliant ncdf files you can simply do:

library(terra)
tmax2 <- rast("E:/SKRIPSI/prec-tmin-tmax-sumut/tmax2006-2022.nc", "TASMAX")
lat <- 1:3
lon <- 98:100
points <- vect(cbind(lon, lat))

e <- extract(tmax2, points)

This only works if the ncdf file has regular raster data. That is not guaranteed, but you provide no information about the file, nor do you provide the file.