Cannot read NC file dimensions values and regrid them

Hello,

I'm trying tot rescale coordinates in the .nc file that has one variable.

ncfile = 'my_file.nc';

ncdisp(ncfile) produces this result;

Format: netcdf4_classic

Dimensions:

lat = 234

lon = 288

Variables:

var

Size: 234x288

Dimensions: lat,lon

Datatype: double

info = ncinfo(ncfile);
dim_lat = info.Variables(strcmp({info.Variables.Name}, 'swr')).Dimensions(strcmp({info.Variables(strcmp({info.Variables.Name}, 'var')).Dimensions.Name}, 'lat')).Name;
dim_lon = info.Variables(strcmp({info.Variables.Name}, 'swr')).Dimensions(strcmp({info.Variables(strcmp({info.Variables.Name}, 'var')).Dimensions.Name}, 'lon')).Name;

But then I'm getting an error when I'm trying to read the values:

lat_existing = ncread(ncfile, dim_lat);
lon_existing = ncread(ncfile, dim_lon);

Error using internal.matlab.imagesci.nc/getGroupAndVarid

Could not find variable or group 'lat' in file.

Error in internal.matlab.imagesci.nc/read (line 648)

[gid, varid] = getGroupAndVarid(this, location);

Error in ncread (line 76)

vardata = ncObj.read(varName, varargin{:});

Answer 1

[MJFcoNaN]

Hello,

"ncread" can only get a variable not a dimention.

There is only a length of any "Dimention", such as lat=234, but no value.

In many cases, you will find some variables under the same or different name with the dimentions, then you can use ncread to get them. For my fake example, ncread(ncfile, "lat"), ncread(ncfile, "longitude") and ncread(ncfile, "lat_matrix") will get the value:

Format:    netcdf4_classic
Dimensions:
           lat = 234
           lon = 288
Variables:
    var
           Size:       234x288
           Dimensions: lat,lon
           Datatype:   double
    lat
           Size:       234
           Dimensions: lat
           Datatype:   double
    longitude
           Size:       288
           Dimensions: lon
           Datatype:   double
    lat_matrix
           Size:       234x288
           Dimensions: lat,lon
           Datatype:   double