Re: New Ticket - [netCDFDecoders !FEG-733021]: Problem reading ECMWF Grib file

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On Tue, 19 Dec 2006, dmurray@xxxxxxxxxxxxxxxxxxxxxxxx wrote:


New Ticket: Problem reading ECMWF Grib file



this is a quasi-regular Grib1 grid, we decided not to do the work since it's 
Grib1.  are we going to bring this up?  last quasi work was 3-5 days effort.  i 
commented out the print in the code so it won't come up in IDV and did another 
grib jar ci.

robb...


Hi Robb-

I have a GRIB file from ECMWF that does not give the correct
navigation:

/upc/share/testdata/grid/grib/grib1/data/ana_Z_20031006_00_ml.grib

When I run Grib1Dump on this, it prints out:

$ java  ucar.grib.grib1.Grib1Dump ana_Z_20031006_00_ml.grib
GDS  numPV[ 0 ] = 0
GDS  numPV[ 1 ] = 0
GDS  numPV[ 2 ] = 16916
GDS  numPV[ 3 ] = 0
GDS  numPV[ 4 ] = 16934
GDS  numPV[ 5 ] = 27875
GDS  numPV[ 6 ] = 16959
GDS  numPV[ 7 ] = -23082
GDS  numPV[ 8 ] = 16991
GDS  numPV[ 9 ] = -23792
GDS  numPV[ 10 ] = 17030
GDS  numPV[ 11 ] = 31674
GDS  numPV[ 12 ] = 17076
GDS  numPV[ 13 ] = -27240
GDS  numPV[ 14 ] = 17130
GDS  numPV[ 15 ] = -14480
GDS  numPV[ 16 ] = 17170
GDS  numPV[ 17 ] = -22545
GDS  numPV[ 18 ] = 17175
GDS  numPV[ 19 ] = 24461
GDS  numPV[ 20 ] = 17181
GDS  numPV[ 21 ] = 2532
GDS  numPV[ 22 ] = 17187
GDS  numPV[ 23 ] = -1429
GDS  numPV[ 24 ] = 17196
GDS  numPV[ 25 ] = -27779
GDS  numPV[ 26 ] = 17207
GDS  numPV[ 27 ] = 14993
GDS  numPV[ 28 ] = 17220
GDS  numPV[ 29 ] = 27995
GDS  numPV[ 30 ] = 17236
GDS  numPV[ 31 ] = -14440
GDS  numPV[ 32 ] = 17257
GDS  numPV[ 33 ] = 2623
GDS  numPV[ 34 ] = 17282
GDS  numPV[ 35 ] = 9314
GDS  numPV[ 36 ] = 17313
GDS  numPV[ 37 ] = 15928
GDS  numPV[ 38 ] = 17351
GDS  numPV[ 39 ] = -14657
GDS  numPV[ 40 ] = 17399
GDS  numPV[ 41 ] = -31574
GDS  numPV[ 42 ] = 17427
GDS  numPV[ 43 ] = 10933
GDS  numPV[ 44 ] = 17431
GDS  numPV[ 45 ] = -32251
GDS  numPV[ 46 ] = 17436
GDS  numPV[ 47 ] = -30046
GDS  numPV[ 48 ] = 17442
GDS  numPV[ 49 ] = 15630
GDS  numPV[ 50 ] = 17448
GDS  numPV[ 51 ] = -30688
GDS  numPV[ 52 ] = 17455
GDS  numPV[ 53 ] = 11634
GDS  numPV[ 54 ] = 17461
GDS  numPV[ 55 ] = -12461
GDS  numPV[ 56 ] = 17468
GDS  numPV[ 57 ] = 5070
GDS  numPV[ 58 ] = 17473
GDS  numPV[ 59 ] = -19591
GDS  numPV[ 60 ] = 17478
GDS  numPV[ 61 ] = 32047
GDS  numPV[ 62 ] = 17482
GDS  numPV[ 63 ] = 21426
GDS  numPV[ 64 ] = 17485
GDS  numPV[ 65 ] = 11036
GDS  numPV[ 66 ] = 17486
GDS  numPV[ 67 ] = -460
GDS  numPV[ 68 ] = 17487
GDS  numPV[ 69 ] = -12835
GDS  numPV[ 70 ] = 17487
GDS  numPV[ 71 ] = -24453
GDS  numPV[ 72 ] = 17486
GDS  numPV[ 73 ] = -32409
GDS  numPV[ 74 ] = 17484
GDS  numPV[ 75 ] = -32684
GDS  numPV[ 76 ] = 17481
GDS  numPV[ 77 ] = -20288
GDS  numPV[ 78 ] = 17478
GDS  numPV[ 79 ] = 10588
GDS  numPV[ 80 ] = 17474
GDS  numPV[ 81 ] = 888
GDS  numPV[ 82 ] = 17469
GDS  numPV[ 83 ] = 23155
GDS  numPV[ 84 ] = 17464
GDS  numPV[ 85 ] = 19232
GDS  numPV[ 86 ] = 17458
GDS  numPV[ 87 ] = -3272
GDS  numPV[ 88 ] = 17453
GDS  numPV[ 89 ] = 28866
GDS  numPV[ 90 ] = 17447
GDS  numPV[ 91 ] = -7808
GDS  numPV[ 92 ] = 17442
GDS  numPV[ 93 ] = 25179
GDS  numPV[ 94 ] = 17437
GDS  numPV[ 95 ] = 3790
GDS  numPV[ 96 ] = 17432
GDS  numPV[ 97 ] = 81
GDS  numPV[ 98 ] = 17427
GDS  numPV[ 99 ] = 19911
GDS  numPV[ 100 ] = 17392
GDS  numPV[ 101 ] = -20835
GDS  numPV[ 102 ] = 17332
GDS  numPV[ 103 ] = 31525
GDS  numPV[ 104 ] = 17280
GDS  numPV[ 105 ] = -902
GDS  numPV[ 106 ] = 17238
GDS  numPV[ 107 ] = -24934
GDS  numPV[ 108 ] = 17205
GDS  numPV[ 109 ] = 30154
GDS  numPV[ 110 ] = 17181
GDS  numPV[ 111 ] = 13654
GDS  numPV[ 112 ] = 17106
GDS  numPV[ 113 ] = 25814
GDS  numPV[ 114 ] = 16961
GDS  numPV[ 115 ] = -7259
GDS  numPV[ 116 ] = 16757
GDS  numPV[ 117 ] = -7610
GDS  numPV[ 118 ] = 0
GDS  numPV[ 119 ] = 0
GDS  numPV[ 120 ] = 0
GDS  numPV[ 121 ] = 0
GDS  numPV[ 122 ] = 0
GDS  numPV[ 123 ] = 0
GDS  numPV[ 124 ] = 0
GDS  numPV[ 125 ] = 0
GDS  numPV[ 126 ] = 0
GDS  numPV[ 127 ] = 0
GDS  numPV[ 128 ] = 0
GDS  numPV[ 129 ] = 0
GDS  numPV[ 130 ] = 0
GDS  numPV[ 131 ] = 0
GDS  numPV[ 132 ] = 0
GDS  numPV[ 133 ] = 0
GDS  numPV[ 134 ] = 0
GDS  numPV[ 135 ] = 0
GDS  numPV[ 136 ] = 0
GDS  numPV[ 137 ] = 0
GDS  numPV[ 138 ] = 0
GDS  numPV[ 139 ] = 0
GDS  numPV[ 140 ] = 0
GDS  numPV[ 141 ] = 0
GDS  numPV[ 142 ] = 0
GDS  numPV[ 143 ] = 0
GDS  numPV[ 144 ] = 0
GDS  numPV[ 145 ] = 0
GDS  numPV[ 146 ] = 0
GDS  numPV[ 147 ] = 0
GDS  numPV[ 148 ] = 0
GDS  numPV[ 149 ] = 0
GDS  numPV[ 150 ] = 0
GDS  numPV[ 151 ] = 0
GDS  numPV[ 152 ] = 0
GDS  numPV[ 153 ] = 0
GDS  numPV[ 154 ] = 0
GDS  numPV[ 155 ] = 0
GDS  numPV[ 156 ] = 0
GDS  numPV[ 157 ] = 0
GDS  numPV[ 158 ] = 0
GDS  numPV[ 159 ] = 0
GDS  numPV[ 160 ] = 0
GDS  numPV[ 161 ] = 0
GDS  numPV[ 162 ] = 0
GDS  numPV[ 163 ] = 0
GDS  numPV[ 164 ] = 0
GDS  numPV[ 165 ] = 0
GDS  numPV[ 166 ] = 0
GDS  numPV[ 167 ] = 0
GDS  numPV[ 168 ] = 0
GDS  numPV[ 169 ] = 0
GDS  numPV[ 170 ] = 15695
GDS  numPV[ 171 ] = -32329
GDS  numPV[ 172 ] = 15902
GDS  numPV[ 173 ] = 15596
GDS  numPV[ 174 ] = 15990
GDS  numPV[ 175 ] = -2748
GDS  numPV[ 176 ] = 16148
GDS  numPV[ 177 ] = -12304
GDS  numPV[ 178 ] = 16173
GDS  numPV[ 179 ] = -23504
GDS  numPV[ 180 ] = 16212

For a particular grid:

--------------------------------------------------------------------
                         Header : GRIB1
                     Discipline : 0 Meteorological Products
                   GRIB Edition : 1
                    GRIB length : 130916
             Originating Center : 98 European Center for Medium-Range
Weather For
ecasts (RSMC)
         Originating Sub-Center : 0 WMO Secretariat
             Product Definition : 0 Forecast/Uninitialized
Analysis/Image Product

             Parameter Category : -1 Meteorological Parameters
                 Parameter Name : 131 U U velocity
                Parameter Units : m s^-1
                 Reference Time : 2003-10-06T00:00:00Z
                     Time Units : hour
           Time Range Indicator : product valid at RT + P1
                    Time 1 (P1) : 0
                    Time 2 (P2) : 0
        Generating Process Type : 203 Unknown
                     Level Type : 109 hybrid level
                  Level Value 1 : 60.0
                  Level Value 2 : 0.0
                     GDS Exists : true
                     BMS Exists : false
          Number of data points : 65160
                      Grid Name : Latitude/Longitude Grid
                      Grid Shape: 0 spherical
          Spherical earth radius: 6367.47
                             Nx : 360
                             Ny : 181
                            La1 : 90.0
                            Lo1 : 0.0
   Resolution & Component flags : 128
                            La2 : -90.0
                            Lo2 : 359.0
                             Dx : -9999.0
                             Dy : 1.0
                  Scanning mode : 0

notice that the Dx is -9999.0.  This ends up creating non-sensical
longitudes.

So, one issue is the debug messages printing out and the other is
the bad longitude values.  This shows up in the tools UI as well as
the IDV.  In the Tools UI, a dump of the longitude variable gives:


    double lon(lon=360);
      :units = "degrees_east";
      :long_name = "longitude coordinate";
      :standard_name = "longitude";
      :grid_spacing = "-9999.0 degrees_east";
      :_CoordinateAxisType = "Lon";

  data:

   {0.0, -9999.0, -19998.0, -29997.0, -39996.0, -49995.0, -59994.0,
-69993.0, -79992.0, -89991.0, -99990.0, -109989.0, -119988.0, -129987.0,
-139986.0, -149985.0, -159984.0, -169983.0, -179982.0, -189981.0,
-199980.0, -209979.0, -219978.0, -229977.0, -239976.0, -249975.0,
-259974.0, -269973.0, -279972.0, -289971.0, -299970.0, -309969.0,
-319968.0, -329967.0, -339966.0, -349965.0, -359964.0, -369963.0,
-379962.0, -389961.0, -399960.0, -409959.0, -419958.0, -429957.0,
-439956.0, -449955.0, -459954.0, -469953.0, -479952.0, -489951.0,
-499950.0, -509949.0, -519948.0, -529947.0, -539946.0, -549945.0,
-559944.0, -569943.0, -579942.0, -589941.0, -599940.0, -609939.0,
-619938.0, -629937.0, -639936.0, -649935.0, -659934.0, -669933.0,
-679932.0, -689931.0, -699930.0, -709929.0, -719928.0, -729927.0,
-739926.0, -749925.0, -759924.0, -769923.0, -779922.0, -789921.0,
-799920.0, -809919.0, -819918.0, -829917.0, -839916.0, -849915.0,
-859914.0, -869913.0, -879912.0, -889911.0, -899910.0, -909909.0,
-919908.0, -929907.0, -939906.0, -949905.0, -959904.0, -969903.0,
-979902.0, -989901.0, -999900.0, -1009899.0, -1019898.0, -1029897.0,
-1039896.0, ....................


There is another file in the directory (ana_Z_20031006_00.grib) from
ECMWF which is on pressure coordinates. It does not have this problem.

Don
*************************************************************
Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
*************************************************************
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