[ncl-talk] Reading ECMWF THREDDS data using OPENDAP

Fri Sep 4 15:29:16 MDT 2015

Hi,

I am trying to read an ECMWF dataset from the NCAR RDA THREDDS servver using NCL.

I am using the example OPENDAP script from NCL but am having trouble accessing the data.

The snippet of the NCL script I am using is below, as is the link to the datasset I am trying to access.

I have sucessfully accessed data using OPENDAP before, so I am hoping that it is just an incorrecct

link-id.  I am running 6.1.2...Thanks...

Dave Vollaro

--------------- code snippet --------------

  url = "http://rda.ucar.edu/thredds/fileServer/aggregations/e/ds627.0/15/"
filename = url + "ERA_Interim_atmospheric_model_forecast_for_surface-198808/files/ei.oper.fc.sfc.regn128sc.1988080100"
print(filename)
;***********************************************
;  DATA SOURCE
;***********************************************

  exists = isfilepresent(filename)
  if(.not.exists) then
    print("OPeNDAP isfilepresent test unsuccessful.")
    print("File doesn't exist or NCL doesn't have OPeNDAP ability on this system")
  else
    print("OPeNDAP isfilepresent test successful.")
    file_nc = addfile(filename,"r")
  end if
  names = getfilevarnames(file_nc)          ;Get the variable names in the
  print(names)                               ;GRIB file and print them out.
end

--------- end snippet-------

  link:
http://rda.ucar.edu/thredds/catalog/aggregations/e/ds627.0/15/ERA_Interim_atmospheric_model_forecast_for_surface-198808/catalog.html?dataset=aggregations/e/ds627.0/15/ERA_Interim_atmospheric_model_forecast_for_surface-198808/files/ei.oper.fc.sfc.regn128sc.1988080100

error:

(0)     http://rda.ucar.edu/thredds/fileServer/aggregations/e/ds627.0/15/ERA_Interim_atmospheric_model_forecast_for_surface-198808/files/ei.oper.fc.sfc.regn128sc.1988080100
syntax error, unexpected WORD_WORD, expecting SCAN_ATTR or SCAN_DATASET or SCAN_ERROR
context: <html^><head><title>Apache Tomcat/7.0.63 - Error report</title><style></style> </head><body><h1>HTTP Status 401 - </h1><HR size="1" noshade="noshade"><p><b>type</b> Status report</p><p><b>message</b> <u></u></p><p><b>description</b> <u>This request requires HTTP authentication.</u></p><HR size="1" noshade="noshade"><h3>Apache Tomcat/7.0.63</h3></body></html>
ncopen: filename "http://rda.ucar.edu/thredds/fileServer/aggregations/e/ds627.0/15/ERA_Interim_atmospheric_model_forecast_for_surface-198808/files/ei.oper.fc.sfc.regn128sc.1988080100": NetCDF: Malformed or inaccessible DAP DDS
(0)     OPeNDAP isfilepresent test unsuccessful.
(0)     File doesn't exist or NCL doesn't have OPeNDAP ability on this system

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