ncinfo

Return information about NetCDF data source

Syntax

finfo = ncinfo(source) vinfo = ncinfo(source,varname) ginfo = ncinfo(source,groupname)

Description

finfo = ncinfo(source) returns information in the structure finfo about the entire NetCDF data source specified by source, where source can be the name of a NetCDF file, the URL of an OPeNDAP NetCDF data source, or the HTTP URL of a remote NetCDF file (with the #mode=bytes suffix for byte-range reading).

vinfo = ncinfo(source,varname) returns information in the structure vinfo about the variable varname in source.

ginfo = ncinfo(source,groupname) returns information in the structure ginfo about the group groupname in source (only NetCDF4 data sources).

Note

Use ncdisp for visual inspection of a NetCDF source.

Input Arguments

source

Character vector or string scalar specifying the name of a NetCDF file, the URL of an OPeNDAP NetCDF data source, or an HTTP URL of a remote NetCDF file for byte-range reading. To enable byte-range reading of remote datasets, append #mode=bytes to the end of the HTTP URL. For details about byte-range reading, consult the NetCDF documentation.

Example: "myNetCDFfile.nc"

varname

Character vector or string scalar specifying the name of a variable in a NetCDF file or OPeNDAP data source.

groupname

Character vector or string scalar specifying the name of a group in a NetCDF file or OPeNDAP data source.

Output Arguments

finfo

A structure with the following fields.

Field	Description
`Filename`	NetCDF file name or OPeNDAP URL
`Name`	`'/'`, indicating the full file
`Dimensions`	An array of structures with these fields:
	`Name`	Dimension name
	`Length`	Current length of dimension
	`Unlimited`	Boolean flag, true for unlimited dimensions
`Variables`	An array of structures with these fields:
	`Name`	Variable name
	`Dimensions`	Associated dimensions
	`Size`	Current variable size
	`Datatype`	MATLAB^® data type or name of the user-defined type
	`Attributes`	Associated variable attributes
	`ChunkSize`	Chunk size, if defined, `[]` otherwise
	`FillValue`	Fill value of the variable
	`DeflateLevel`	Deflate filter level, if enabled
	`Shuffle`	Shuffle filter enabled flag
`Attributes`	An array of global attributes with these fields:
	`Name`	Attribute name
	`Value`	Attribute value
`Groups`	An array of groups present in the file for `netcdf4` files. An empty array (`[]`) for all other NetCDF file formats.
`Format`	Format of the NetCDF file
`Datatypes`	An array of structures containing information about each supported user-defined type in the NetCDF file with these fields (empty for files with no user-defined types):
	`Name`	Type name
	`Class`	Class (for `NC_VLEN` types, contains `NC_VLEN`)
	`Type`	Type-specific information (for `NC_VLEN` types, contains base type as a MATLAB data type)
	`ByteSize`	Size of the type in bytes

vinfo

A structure containing only the variable fields from finfo.

Field	Description
`Filename`	NetCDF file name
`Name`	Name of the variable
`Dimensions`	Dimensions of the variable
`Size`	Size of the current variable
`Datatype`	MATLAB data type or name of the user-defined type
`Attributes`	Attributes associated with the variable
`ChunkSize`	Chunk size, if defined; otherwise, `[]`
`FillValue`	Fill value used in the variable
`DeflateLevel`	Deflate filter level, if enabled
`Shuffle`	Shuffle filter enabled flag
`Format`	Format of the NetCDF file

ginfo

A structure containing only the group fields from finfo.

Field	Description
`Filename`	NetCDF file name
`Name`	Name of the group
`Dimensions`	Only dimensions defined in the specified group
`Variables`	Only variables defined in the specified group
`Attributes`	Attributes associated with the variable
`Groups`	Names of groups, if defined; otherwise, `[]`
`Format`	Format of the NetCDF file

Examples

Search for dimensions with names that start with the character x in the file.

finfo = ncinfo('example.nc');
disp(finfo);
dimNames = {finfo.Dimensions.Name};
dimMatch = strncmpi(dimNames,'x',1);
disp(finfo.Dimensions(dimMatch));

Obtain the size of a variable and check if it has any unlimited dimensions.

vinfo = ncinfo('example.nc','peaks');
varSize = vinfo.Size;
disp(vinfo);
hasUnLimDim = any([vinfo.Dimensions.Unlimited]);

Find all unlimited dimensions defined in a group.

ginfo = ncinfo('example.nc','/grid2/');
unlimDims = [ginfo.Dimensions.Unlimited];
disp(ginfo.Dimensions(unlimDims));

Limitations

The performance of byte-range reading is slower than reading from other sources.

Version History

Introduced in R2011a