[R] OPeNDAP access / OPeNDAP subsetting with R

[Debasish Pai Mazumder]

Hi
Now I am using netcdfSubset and I am able to download the file but not sure
how to read the files. here my scripts
library("ncdf4")

gribfile<-"
http://thredds.ucar.edu/thredds/ncss/grib/NCEP/GFS/Pacific_40km/best/dataset.html
"
download.file(gribfile,basename(gribfile),mode = "wb")
x<-nc_open(gribfile)

gribfile<-"
http://thredds.ucar.edu/thredds/ncss/grib/NCEP/GFS/Global_0p5deg/best?north=47.0126&west=-114.841&east=-112.641&south=44.8534&time_start=present&time_duration=PT3H&accept=netcdf&var=v-component_of_wind_height_above_ground,u-component_of_wind_height_above_ground"

download.file(gribfile,basename(gribfile),mode = "wb")
x<-nc_open(gribfile)


nc_open doesn't work.

which command should I use?

with regards
-Deb


On Tue, Sep 27, 2016 at 9:30 PM, Michael Sumner <mdsumner at gmail.com> wrote:

> Opendap won't work on Windows CRAN build of ncdf4, though the rgdal build
> does work directly on grib.
>
> Summary: download the files wholus for use on Windows, or set your own
> system on Linux.
>
> Building ncdf4 on Windows is not too hard if you know about doing that.
>
> Cheers, Mike
>
> On Wed, 28 Sep 2016, 06:49 Roy Mendelssohn - NOAA Federal <
> roy.mendelssohn at noaa.gov> wrote:
>
>> Please post the code of what you tried, as I have no idea otherwise what
>> did or did not work for you.
>>
>> -Roy
>>
>> > On Sep 27, 2016, at 12:44 PM, Debasish Pai Mazumder <pai1981 at gmail.com>
>> wrote:
>> >
>> > Hi Roy,
>> > Thanks for your response. I have tried according your suggestion but it
>> doesn't work.
>> > the OPeNDAP link of the data
>> > http://nomads.ncdc.noaa.gov/thredds/dodsC/modeldata/cfsv2_
>> forecast_ts_9mon/2014/201404/20140403/2014040312/
>> >
>> > datafile:
>> > tmax.01.2014040312.daily.grb2
>> >
>> > Thanks
>> > -Deb
>> >
>> > On Tue, Sep 27, 2016 at 11:51 AM, Roy Mendelssohn - NOAA Federal <
>> roy.mendelssohn at noaa.gov> wrote:
>> > Look at the package ncdf4.  You can use an OPeNDAP URL in place of the
>> file name to perform subsets.,
>> >
>> > -Roy
>> >
>> > > On Sep 27, 2016, at 9:06 AM, Debasish Pai Mazumder <pai1981 at gmail.com>
>> wrote:
>> > >
>> > > Hi all,
>> > >
>> > > I would like to access and subset following OpeNDAP files.
>> > > server:
>> > > http://nomads.ncdc.noaa.gov/thredds/dodsC/modeldata/cfsv2_
>> forecast_ts_9mon/2014/201404/20140403/2014040312/
>> > >
>> > > file name: tmax.01.2014040312.daily.grb2
>> > > <http://nomads.ncdc.noaa.gov/thredds/dodsC/modeldata/cfsv2_
>> forecast_ts_9mon/2014/201404/20140403/2014040312/catalog.
>> html?dataset=modeldata/cfsv2_forecast_ts_9mon/2014/201404/
>> 20140403/2014040312/tmax.01.2014040312.daily.grb2>
>> > > I would like to access and subset the file. Any help will be
>> appreciated.
>> > >
>> > > with regards
>> > > -Deb
>> > >
>> > >       [[alternative HTML version deleted]]
>> > >
>> > > ______________________________________________
>> > > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> > > https://stat.ethz.ch/mailman/listinfo/r-help
>> > > PLEASE do read the posting guide http://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 address and phone***
>> > 110 Shaffer Road
>> > Santa Cruz, CA 95060
>> > Phone: (831)-420-3666
>> > Fax: (831) 420-3980
>> > e-mail: Roy.Mendelssohn at noaa.gov www: http://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.
>> >
>> >
>>
>> **********************
>> "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 address and phone***
>> 110 Shaffer Road
>> Santa Cruz, CA 95060
>> Phone: (831)-420-3666
>> Fax: (831) 420-3980
>> e-mail: Roy.Mendelssohn at noaa.gov www: http://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 at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/
>> posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
> --
> Dr. Michael Sumner
> Software and Database Engineer
> Australian Antarctic Division
> 203 Channel Highway
> Kingston Tasmania 7050 Australia
>
>

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