[gradsusr] NETCDF4 problem

[jorge.conrado at cptec.inpe.br]

Hi,


I have some NDI data in netcdf4 format, here is the result of the 
ncdfdump for my data:


  ncdump -h ndvi3g_geo_v1_1981_0712.nc4
netcdf ndvi3g_geo_v1_1981_0712 {
dimensions:
         lon = 4320 ;
         lat = 2160 ;
         time = 12 ;
variables:
         double lon(lon) ;
         double lat(lat) ;
         double time(time) ;
         short satellites(time) ;
         short ndvi(time, lat, lon) ;
                 ndvi:units = "1" ;
                 ndvi:scale = "x 10000" ;
                 ndvi:missing_value = -5000. ;
                 ndvi:valid_range = -0.3, 1. ;
         short percentile(time, lat, lon) ;
                 percentile:units = "%" ;
                 percentile:scale = "x 10" ;
                 percentile:flags = "flag 0: from data                
flag 1: spline interpolation     flag 2: possible snow/cloud cover" ;
                 percentile:valid_range = "flag*2000 + [0 1000]" ;

// global attributes:
                 :FileName = "ndvi3g_geo_v1_1981_0712.nc4" ;
                 :Institution = "NASA/GSFC GIMMS" ;
                 :Data = "NDVI3g version 1" ;
                 :Reference = "1. Pinzon, J.E.; Tucker, C.J.              
                            A Non-Stationary 1981-2012 AVHRR NDVI3g Time 
Series.                Remote Sens. 2014, 6, 6929-6960.                  
                 2. Pinzon, J.E.; Tucker, C.J.                            
              A Non-Stationary 1981-2015 AVHRR NDVI3g.v1 Time Series: an 
update.  Remote Sens. 2016, in preparation                               
   " ;
                 :CommentsVersion1 = "version1 includes two major fixes 
(a and b), and three minor (c-g):     (a) Reprocessed Level 2 entire 
SeaWIFS mission for the land products       to reduce artifacts in the 
data, particularly changes in calibration    after 2006 that generates 
drops in ndvi lower values.                   OB.DAAC / Ocean Biology 
Processing group NASA/GSFC 616  (april 2016) (b) Recovered ndvi negative 
values of snow-covered regions in winter       Northern latitudes.  In 
Version0, we masked them with zero values,      creating artifacts in 
phenology parameters.                          (c) Arranged data in ncd 
format, compiled it in two nc4 files a year.       Each nc4 file 
includes 6 months of ndvi data (jan-jun and jul-dec),     with a total 
of 12 (15-day) composites each semester.               (d) Rescaled ndvi 
values and splitted the flag values from them.        (e) Added a new 
variable, percentile, to represent the distribution of      ndvi values 
in the time series. Range 10*[0, 100]                   (f) Flag values 
are (simpler):                                              flag 0: ndvi 
without apparent issues (good value)                       flag 1: ndvi 
retrieved from spline interpolation                        flag 2: ndvi 
retrieved from seasonal profile (possible snow/cloud)  (g) Flag values 
are embeded on the percentile variable:                     2000*flag + 
percentile. Thus, the actual percentile three ranges        [0 1000], 
[2000 3000] and [4000 5000] could provide direct              
information of how interpolation is affecting the time series.      " ;
                 :Temporalrange = "1981-07-01 -> 2015-12-31" ;
                 :Year = 1981. ;
                 :RangeSemester = "Jul 1 - Dec 31 (7:0.5:12.5)" ;
                 :SpatialResolution = "1/12 x 1/12 degrees" ;
                 :TemporalResolution = "1/24 a year" ;
                 :_fill_val = -32768. ;
                 :NorthernmostLatitude = "90" ;
                 :SouthernmostLatitude = "-90" ;
                 :WesternmostLongitude = "-180" ;
                 :EasternmostLongitude = "180" ;
}


Then I did:  grads -p

sdfopen ndvi3g_geo_v1_1981_0712.nc4

and I had:

Scanning self-describing file:  ndvi3g_geo_v1_1981_0712.nc4
gadsdf: SDF file has no discernable X coordinate.


Please, what can I do to solve this.



Thanks,


Conrado