latitude and longitude seen as variable instead of dimension in netCDF file.
Added by Meenakshi Sreejith about 2 years ago
Hello all,
I have a netCDF file with one variable(SST) over 12784 timesteps. It is a global 1degree data. But the latitude and longitude dimensions are shown as variables and hence the SST variable is only depending on time dimension. How can i convert lat and lon into dimensions? SHown below is the header of my netCDF file:
netcdf sst_newEc {
dimensions:
time = UNLIMITED ; // (12784 currently)
bnds = 2 ;
vertices = 4 ;
variables:
double time(time) ;
time:standard_name = "time" ;
time:long_name = "time" ;
time:bounds = "time_bnds" ;
time:units = "days since 1850-01-01 00:00:00" ;
time:calendar = "proleptic_gregorian" ;
time:axis = "T" ;
double time_bnds(time, bnds) ;
double longitude ;
longitude:standard_name = "longitude" ;
longitude:long_name = "longitude" ;
longitude:units = "degrees_east" ;
longitude:_CoordinateAxisType = "Lon" ;
longitude:bounds = "longitude_bnds" ;
longitude:cell_methods = "i: mean j: mean" ;
double longitude_bnds(vertices) ;
longitude_bnds:cell_methods = "i: mean j: mean" ;
double latitude ;
latitude:standard_name = "latitude" ;
latitude:long_name = "latitude" ;
latitude:units = "degrees_north" ;
latitude:_CoordinateAxisType = "Lat" ;
latitude:bounds = "latitude_bnds" ;
latitude:cell_methods = "i: mean j: mean" ;
double latitude_bnds(vertices) ;
latitude_bnds:cell_methods = "i: mean j: mean" ;
int i ;
i:standard_name = "projection_x_coordinate" ;
i:long_name = "cell index along first dimension" ;
i:units = "1" ;
i:axis = "X" ;
i:cell_methods = "i: mean" ;
int j ;
j:standard_name = "projection_y_coordinate" ;
j:long_name = "cell index along second dimension" ;
j:units = "1" ;
j:axis = "Y" ;
j:cell_methods = "j: mean" ;
float tos(time) ;
tos:standard_name = "sea_surface_temperature" ;
tos:long_name = "Sea Surface Temperature" ;
tos:units = "degC" ;
tos:coordinates = "latitude longitude" ;
tos:_FillValue = 1.e+20f ;
tos:missing_value = 1.e+20f ;
tos:comment = "Temperature of upper boundary of the liquid ocean, including temperatures below sea-ice and floating ice shelves." ;
tos:original_name = "tos" ;
tos:cell_methods = "area: mean where sea time: mean i: mean j: mean" ;
tos:cell_measures = "area: areacello" ;
tos:history = "2019-09-26T10:20:17Z altered by CMOR: Reordered dimensions, original order: j i time." ;
Replies (9)
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Karin Meier-Fleischer about 2 years ago
Hi Meenakshi,
the variable tos depends only on time, and the latitude and longitude variables are just 1 point.
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Meenakshi Sreejith about 2 years ago
How can I add latitude and longitude to it? In the metadata it was shown as a 3-D file
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Karin Meier-Fleischer about 2 years ago
Can you upload the data (1 time step)?
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Meenakshi Sreejith about 2 years ago
Hello Karin
The earlier header was that of a file on which some modifications were done. The given file is the original version .
| onestep.nc (5.78 MB) onestep.nc |
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Karin Meier-Fleischer about 2 years ago
The coordinates are missing.
ncdump -h onestep.nc
netcdf onestep {
dimensions:
X = 1442 ;
Y = 1050 ;
TIME = UNLIMITED ; // (1 currently)
variables:
double TIME(TIME) ;
TIME:axis = "T" ;
TIME:long_name = "Time axis" ;
TIME:calendar = "gregorian" ;
TIME:units = "days since 1850-01-01 00:00:00" ;
TIME:time_origin = "1850-01-01 00:00:00" ;
TIME:standard_name = "time" ;
float TOS(TIME, Y, X) ;
TOS:missing_value = 1.e+20f ;
TOS:_FillValue = 1.e+20f ;
TOS:long_name = "Sea Surface Temperature" ;
TOS:units = "degC" ;
TOS:history = "none" ;
// global attributes:
:history = "FERRET V7.3 (optimized) 24-Nov-22" ;
:Conventions = "CF-1.6" ;
}
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Meenakshi Sreejith about 2 years ago
Hello Karin
How can I add dimensions to this tos variable? I wanted to make an index using this variable. Therefore, when I tried to give coordinates, it was not working.
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Karin Meier-Fleischer about 2 years ago
You need to get the associated coordinates from where you got the data file.
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Meenakshi Sreejith about 2 years ago
Hello
I downloaded the data from CMIP6 website. Is there any way i can add axis to this file?
RE: latitude and longitude seen as variable instead of dimension in netCDF file. - Added by Estanislao Gavilan about 2 years ago
Hi,
If you downloaded the data from CMIP6 website, it should have a variable for longitude and latitude. Now, if you edited the file by yourself you migh have forgotten to add the coordiantes. Take a look to the original file, and make sure that you have all the information.
Kind regards,
Estanislao