[gradsusr] Opening a file having overlapping longitude points.

James T. Potemra jimp at hawaii.edu
Tue Mar 29 13:55:21 EDT 2011


Martin:

This ctl file works for a similar data set:
> DSET    ^oscar-4bc40f4cf0406.nc
> DTYPE   netcdf
> OPTIONS yrev
> TITLE   OSCAR long-term mean velocity
> UNDEF   0.0
> XDEF    400 linear  20.5 1.0
> YDEF    120 linear -59.5 1.0
> ZDEF      1 linear   1.0 1.00
> TDEF      1 linear 01jan2010 1mo
> @ global String comment wrap
> VARS      2
> u=>uvel   0 t,z,y,x zonal velocity
> v=>vvel   0 t,z,y,x meridional velocity
> ENDVARS
Jim


Martin V. Mathew wrote:
> Hai All
>
> I have a problem in opening an ocean current data in NetCDF format, 
> downloaded from URL
> http://www.oscar.noaa.gov/datadisplay/index.html
>
> It is a 1degree resolution file with 400 longitude points.
> It is given in the documentation of the data that
>
> 'Longitude extends from 20.5 E to 419.5 E to avoid a break in major 
> ocean basins.
> Data repeats in overlap region.'
>
> Dimensions of the data is as  follows
>
> *****************************************************************************************
>         time = 12 ;
>         depth = 1 ;
>         lat = 120 ;
>         lon = 400 ;
>
>  lat = 59.5, 58.5, 57.5, 56.5,.................................
>     
> ................................................................................., 
> -57.5, -58.5, -59.5 ;
>
>  lon = 20.5, 21.5, 22.5, 23.5,.....................
>     ..............., 357.5,358.5, 359.5, 360.5, 361.5, 362.5, 363.5, 
> 364.5,
>     365.5, 366.5, 367.5, 368.5, 369.5, 370.5, 371.5, 372.5, 373.5, 374.5,
>     375.5, 376.5, 377.5, 378.5, 379.5, 380.5, 381.5, 382.5, 383.5, 384.5,
>     385.5, 386.5, 387.5, 388.5, 389.5, 390.5, 391.5, 392.5, 393.5, 394.5,
>     395.5, 396.5, 397.5, 398.5, 399.5, 400.5, 401.5, 402.5, 403.5, 404.5,
>     405.5, 406.5, 407.5, 408.5, 409.5, 410.5, 411.5, 412.5, 413.5, 414.5,
>     415.5, 416.5, 417.5, 418.5, 419.5 ;
> *****************************************************************************************
>
> While trying to open the file in GrADS using sdfopen following error 
> message is displayed
> ------------------------------------------------------------------------------------
> Scanning self-describing file:  oscar-4cff2332a2540_1995.nc 
> <http://oscar-4cff2332a2540_1995.nc>
> gadsdf: SDF file has no discernable X coordinate.
> ------------------------------------------------------------------------------------
>
> I also tried to open the file using a control file in which I defined 
> longitude as follows
>
>   DSET oscar-4cff2332a2540_1995.nc <http://oscar-4cff2332a2540_1995.nc>
>     XDEF lon 400 LEVELS  20.5, 21.5, 22.5, 23.5, .........................
>     
> ..........................................................................................................................
>     .............., 355.5, 356.5, 357.5, 358.5, 359.5,.5,1.5,2.5, 
> 3.5,............
>     
> .....................................................................,55.5,56.5,57.5,58.5,59.5
>
>
> I couldn't open the file using this method also.
> While trying to open the file following error message is displayed
>
> ------------------------------------------------------------------------------------
> ga-> xdfopen oscar-4cff2332a2540_1995.ctl
> Scanning Descriptor File:  oscar-4cff2332a2540_1995.ctl
> Open Error:  Unexpected EOF reading descriptor file
>    EOF occurred reading LEVELS values
>   --> The invalid description file record is:
>   -->     
> 46.5,47.5,48.5,49.5,50.5,51.5,52.5,53.5,54.5,55.5,56.5,57.5,58.5,59.5
>
>   The data file was not opened.
> ga->
> ------------------------------------------------------------------------------------
>
> Somebody please give me a suggestion to solve this problem.
>
> Thanking you
>
> Martin V. Mathew
> J.R.F.
> Centre for Oceans, Rivers, Atmosphere and Land Sciences (CORAL)
> IIT Kharagpur
> India.
>
> ------------------------------------------------------------------------
>
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