[R] Problem with converting grib file to excel

Thu Sep 26 22:26:18 CEST 2024

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On Thu, 26 Sep 2024, 21:22 javad bayat, <j.bayat194 using gmail.com> wrote:

> Dear Roy,
> Sorry for my mistake, I thought I have uploaded the grib file.
> I really apologise for that. I will send it   on Saturday.
> Thank you very much.
>
> On Thu, 26 Sept 2024, 17:40 Roy Mendelssohn - NOAA Federal, <
> roy.mendelssohn using noaa.gov> wrote:
>
> > Hi Javad:
> >
> > I know a lot about reading GRIB files,  I work with them all the time.
> > But if you don’t make the file available,  or point me to where I can
> > download it,  there is not much I can do.
> >
> > Thanks,
> >
> > -Roy
> >
> > On Sep 25, 2024, at 9:41 PM, javad bayat <j.bayat194 using gmail.com> wrote:
> >
> > Dear all;
> > Many thanks for your responses. Actually it is not completely a GIS file,
> > it is a data file which stores meteorological data of a specific region.
> > But the site allows downloading with grib format and as I searched to
> read
> > this type of file in R, I found the Raster Package.
> > In python it is possible to do this using cdsapi and xarray library, but
> I
> > am not familiar with python.
> > Sincerely
> >
> > On Thu, Sep 26, 2024 at 2:33 AM Roy Mendelssohn - NOAA Federal via
> R-help <
> > r-help using r-project.org> wrote:
> >
> >> At least for me the dataset file did not come through.  I will look at
> it
> >> if it can be made available.  It does look like the finial step of
> reading
> >> the data into raster failed,  so then did the rest of th commands.
> >>
> >> -Roy
> >>
> >>
> >> > On Sep 25, 2024, at 3:24 PM, CALUM POLWART <polc1410 using gmail.com>
> wrote:
> >> >
> >> > Noticeable lack of silence in the group on this one.
> >> >
> >> > I've not got time to test currently. But my experience of geo location
> >> > files - they often had more than 2 dimensional data. In other words
> you
> >> > might have a boundary of a region as an object with long and lat for
> >> maybe
> >> > 100 data points making up the region. So 200 pieces of data. All held
> >> as a
> >> > list or something similar in a single "cell" as excel would refer to
> it.
> >> >
> >> > My gut feeling is that's likely to make export to excel difficult
> >> without
> >> > data carpentry first?
> >> >
> >> > On Tue, 24 Sep 2024, 21:26 Bert Gunter, <bgunter.4567 using gmail.com>
> wrote:
> >> >
> >> >> You might try posting on r-sig-geo if you don't get a satisfactory
> >> >> response here. I assume there's a lot of expertise there on handling
> >> >> raster-type data.
> >> >>
> >> >> Cheers,
> >> >> Bert
> >> >>
> >> >> On Mon, Sep 23, 2024 at 11:31 PM javad bayat <j.bayat194 using gmail.com>
> >> wrote:
> >> >>>
> >> >>> Dear R users;
> >> >>> I have downloaded a grib file format (Met.grib) and I want to export
> >> its
> >> >>> data to excel file. Also I want to do some mathematic on some
> columns.
> >> >> But
> >> >>> I got error. I would be more than happy if anyone can help me to do
> >> >> this. I
> >> >>> have provided the codes and the Met.grib file in this email.
> >> >>> Sincerely yours
> >> >>>
> >> >>> # Load the necessary libraries
> >> >>>> library(raster)      # For reading GRIB files
> >> >>>> library(dplyr)       # For data manipulation
> >> >>>> library(lubridate)   # For date manipulation
> >> >>>> library(openxlsx)    # For writing Excel files
> >> >>>
> >> >>> # Specify the file paths
> >> >>>> grib_file_path <- "C:/Users/Omrab_Lab/Downloads/Met.grib"
> >> >>>> excel_file_path <- "C:/Users/Omrab_Lab/Downloads/Met_updated.xlsx"
> >> >>>
> >> >>> # Open the GRIB file
> >> >>>> raster_data <- stack(grib_file_path)
> >> >>>
> >> >>> # Check the names of the layers to identify which ones to extract
> >> >>>> layer_names <- names(raster_data)
> >> >>>> print(layer_names)  # Prints
> >> >>>
> >> >>>
> >> >>>> # Extract layers based on layer names - adjust as necessary
> >> >>>> t2m <- raster_data[[grep("t2m", layer_names)]]
> >> >>>> d2m <- raster_data[[grep("d2m", layer_names)]]
> >> >>>> tcc <- raster_data[[grep("tcc", layer_names)]]
> >> >>>> valid_time <- raster_data[[grep("valid_time", layer_names)]]
> >> >>>> t2m
> >> >>> class      : RasterStack
> >> >>> nlayers    : 0
> >> >>>
> >> >>>> # Check if the raster layers are loaded correctly
> >> >>>> if (is.null(t2m) || is.null(d2m) || is.null(tcc) ||
> >> >> is.null(valid_time))
> >> >>> {
> >> >>> +     stop("One or more raster layers could not be loaded. Please
> >> check
> >> >> the
> >> >>> layer names.")
> >> >>> + }
> >> >>>
> >> >>>> # Convert raster values to vectors
> >> >>>> t2m_values <- values(t2m)
> >> >>> Error in dimnames(x) <- dn :
> >> >>>  length of 'dimnames' [2] not equal to array extent
> >> >>>> d2m_values <- values(d2m)
> >> >>> Error in dimnames(x) <- dn :
> >> >>>  length of 'dimnames' [2] not equal to array extent
> >> >>>> tcc_values <- values(tcc)
> >> >>> Error in dimnames(x) <- dn :
> >> >>>  length of 'dimnames' [2] not equal to array extent
> >> >>>> valid_time_values <- values(valid_time)
> >> >>> Error in dimnames(x) <- dn :
> >> >>>  length of 'dimnames' [2] not equal to array extent
> >> >>>
> >> >>> # Check for NA values and dimensions
> >> >>> if (any(is.na(t2m_values)) || any(is.na(d2m_values)) || any(is.na
> >> >> (tcc_values))
> >> >>> || any(is.na(valid_time_values))) {
> >> >>>  warning("One or more layers contain NA values. These will be
> >> removed.")
> >> >>> }
> >> >>>
> >> >>> # Create the data frame, ensuring no NA values are included
> >> >>> df <- data.frame(
> >> >>>  t2m = t2m_values,
> >> >>>  d2m = d2m_values,
> >> >>>  tcc = tcc_values,
> >> >>>  valid_time = valid_time_values,
> >> >>>  stringsAsFactors = FALSE
> >> >>> )
> >> >>>
> >> >>> # Remove rows with NA values
> >> >>> df <- na.omit(df)
> >> >>>
> >> >>> # Convert temperatures from Kelvin to Celsius
> >> >>> df$t2m <- df$t2m - 273.15
> >> >>> df$d2m <- df$d2m - 273.15
> >> >>>
> >> >>> # Calculate relative humidity
> >> >>> calculate_relative_humidity <- function(t2m, d2m) {
> >> >>>  es <- 6.112 * exp((17.67 * t2m) / (t2m + 243.5))
> >> >>>  e <- 6.112 * exp((17.67 * d2m) / (d2m + 243.5))
> >> >>>  rh <- (e / es) * 100
> >> >>>  return(rh)
> >> >>> }
> >> >>> df$RH <- calculate_relative_humidity(df$t2m, df$d2m)
> >> >>>
> >> >>> # Convert valid_time from numeric to POSIXct assuming it's in
> seconds
> >> >> since
> >> >>> the epoch
> >> >>> df$valid_time <- as.POSIXct(df$valid_time, origin = "1970-01-01")
> >> >>>
> >> >>> # Extract year, month, day, and hour from valid_time
> >> >>> df$Year <- year(df$valid_time)
> >> >>> df$Month <- month(df$valid_time)
> >> >>> df$Day <- day(df$valid_time)
> >> >>> df$Hour <- hour(df$valid_time)
> >> >>>
> >> >>> # Select only the desired columns
> >> >>> df_selected <- df %>% select(Year, Month, Day, Hour, tcc, t2m, RH)
> >> >>>
> >> >>> # Save the updated DataFrame to an Excel file
> >> >>> write.xlsx(df_selected, excel_file_path, row.names = FALSE)
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>> --
> >> >>> Best Regards
> >> >>> Javad Bayat
> >> >>> M.Sc. Environment Engineering
> >> >>> Alternative Mail: bayat194 using yahoo.com
> >> >>>
> >> >>>        [[alternative HTML version deleted]]
> >> >>>
> >> >>> ______________________________________________
> >> >>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> >>> https://stat.ethz.ch/mailman/listinfo/r-help
> >> >>> PLEASE do read the posting guide
> >> >> https://www.R-project.org/posting-guide.html
> >> <https://www.r-project.org/posting-guide.html>
> >> >>> and provide commented, minimal, self-contained, reproducible code.
> >> >>
> >> >> ______________________________________________
> >> >> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> >> https://stat.ethz.ch/mailman/listinfo/r-help
> >> >> PLEASE do read the posting guide
> >> >> https://www.R-project.org/posting-guide.html
> >> <https://www.r-project.org/posting-guide.html>
> >> >> and provide commented, minimal, self-contained, reproducible code.
> >> >>
> >> >
> >> >       [[alternative HTML version deleted]]
> >> >
> >> > ______________________________________________
> >> > R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> > https://stat.ethz.ch/mailman/listinfo/r-help
> >> > PLEASE do read the posting guide
> >> https://www.R-project.org/posting-guide.html
> >> <https://www.r-project.org/posting-guide.html>
> >> > and provide commented, minimal, self-contained, reproducible code.
> >>
> >> **********************
> >> "The contents of this message do not reflect any position of the U.S.
> >> Government or NOAA."
> >> **********************
> >> Roy Mendelssohn
> >> Supervisory Operations Research Analyst
> >> NOAA/NMFS
> >> Environmental Research Division
> >> Southwest Fisheries Science Center
> >> ***Note new street address***
> >> 110 McAllister Way
> >> Santa Cruz, CA 95060
> >> Phone: (831)-420-3666
> >> Fax: (831) 420-3980
> >> e-mail: Roy.Mendelssohn using noaa.gov www: https://www.pfeg.noaa.gov/
> >>
> >> "Old age and treachery will overcome youth and skill."
> >> "From those who have been given much, much will be expected"
> >> "the arc of the moral universe is long, but it bends toward justice"
> -MLK
> >> Jr.
> >>
> >> ______________________________________________
> >> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> https://stat.ethz.ch/mailman/listinfo/r-help
> >> PLEASE do read the posting guide
> >> https://www.R-project.org/posting-guide.html
> >> <https://www.r-project.org/posting-guide.html>
> >> and provide commented, minimal, self-contained, reproducible code.
> >>
> >
> >
> > --
> > Best Regards
> > Javad Bayat
> > M.Sc. Environment Engineering
> > Alternative Mail: bayat194 using yahoo.com
> >
> >
> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> https://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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