NetCDF Files

Network Common Data Form

Network Common Data Form (netCDF) is a set of software libraries and machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. You can interact with netCDF files in several ways:

The Import Tool app (in MATLAB^® Online™) and the Import Data Live Editor task provide intuitive graphical interfaces for exploring and reading data from netCDF files.
The MATLAB high-level netCDF functions provide a simplified programmatic interface for reading data from netCDF files and writing data from the MATLAB workspace to netCDF files.
The MATLAB low-level netCDF functions provide finer control over the reading and writing process of netCDF files by providing access to more than 50 functions in the netCDF C library.
To use the MATLAB low-level netCDF functions, you must be familiar with netCDF C API programming concepts, described at https://www.unidata.ucar.edu/software/netcdf/.

MATLAB uses netCDF C library version 4.9.2.

Live Editor Tasks

Import Data

Import data from a file in the Live Editor (Since R2023a)

Apps

Import Tool

Import data from file

Functions

expand all

High-Level Functions for NetCDF Files

`nccreate`	Create variable in netCDF file
`ncdisp`	Display contents of netCDF data source in Command Window
`ncinfo`	Return information about netCDF data source
`ncread`	Read data from variable in netCDF data source
`ncreadatt`	Read attribute from netCDF data source
`ncwrite`	Write data to netCDF file
`ncwriteatt`	Write attribute to netCDF file
`ncwriteschema`	Add netCDF schema definitions to netCDF file

Low-Level Functions for NetCDF Files

Library Functions

`netcdf.getChunkCache`	Return default chunk cache settings for netCDF library
`netcdf.inqLibVers`	Return netCDF library version information
`netcdf.setChunkCache`	Set default chunk cache settings for netCDF library
`netcdf.setDefaultFormat`	Change default netCDF file format

File Operations

`netcdf.abort`	Revert recent netCDF file definitions
`netcdf.close`	Close netCDF file
`netcdf.create`	Create new netCDF dataset
`netcdf.endDef`	End netCDF file define mode
`netcdf.inq`	Return information about netCDF file
`netcdf.inqFormat`	Determine format of netCDF file
`netcdf.inqGrps`	Return array of child group IDs
`netcdf.inqUnlimDims`	Return IDs of all visible unlimited dimensions in group
`netcdf.open`	Open netCDF data source
`netcdf.reDef`	Put open netCDF file into define mode
`netcdf.setFill`	Set netCDF fill mode
`netcdf.sync`	Synchronize netCDF file to disk

Dimensions

`netcdf.defDim`	Create netCDF dimension
`netcdf.inqDim`	Return netCDF dimension name and length
`netcdf.inqDimID`	Return dimension ID
`netcdf.renameDim`	Change name of netCDF dimension

Groups

`netcdf.defGrp`	Create group in netCDF file
`netcdf.inqDimIDs`	Return list of dimension identifiers in group
`netcdf.inqGrpName`	Return name of group
`netcdf.inqGrpNameFull`	Complete pathname of group
`netcdf.inqGrpParent`	Return ID of parent group
`netcdf.inqNcid`	Return ID of group
`netcdf.inqVarIDs`	Return IDs of all variables in group

Variables

`netcdf.defVar`	Create netCDF variable
`netcdf.defVarChunking`	Define chunking parameters for netCDF variable
`netcdf.defVarDeflate`	Define compression parameters for netCDF variable
`netcdf.defVarFill`	Define fill parameters for netCDF variable
`netcdf.defVarFletcher32`	Define checksum parameters for netCDF variable
`netcdf.getVar`	Read data from netCDF variable
`netcdf.inqVar`	Information about netCDF variable
`netcdf.inqVarChunking`	Return chunking parameters for netCDF variable
`netcdf.inqVarDeflate`	Return compression parameters for netCDF variable
`netcdf.inqVarFill`	Return fill parameters for netCDF variable
`netcdf.inqVarFletcher32`	Return checksum parameters for netCDF variable
`netcdf.inqVarID`	Return ID associated with variable name
`netcdf.putVar`	Write data to netCDF variable
`netcdf.renameVar`	Change name of netCDF variable

Attributes

`netcdf.copyAtt`	Copy attribute to new location
`netcdf.delAtt`	Delete netCDF attribute
`netcdf.getAtt`	Return netCDF attribute
`netcdf.inqAtt`	Return information about netCDF attribute
`netcdf.inqAttID`	Return ID of netCDF attribute
`netcdf.inqAttName`	Return name of netCDF attribute
`netcdf.putAtt`	Write data to netCDF attribute
`netcdf.renameAtt`	Change name of netCDF attribute

User-Defined Types

`netcdf.defVlen`	Define user-defined variable length array type (NC_VLEN) (Since R2022a)
`netcdf.inqUserType`	Return information about user-defined type (Since R2022a)
`netcdf.inqVlen`	Return information about user-defined `NC_VLEN` type (Since R2022a)

Utilities

`netcdf.getConstant`	Return numeric value of named constant
`netcdf.getConstantNames`	Return list of constants known to netCDF library

Topics

Import NetCDF Files and OPeNDAP Data
Read data from a netCDF file using the high-level functions, the low-level functions, and the Import Data Live Editor task.
Export to NetCDF Files
Create, merge, and write netCDF files using high-level functions and the netcdf namespace low-level functions.
Map NetCDF API Syntax to MATLAB Syntax
The low-level functions in the MATLAB netcdf namespace map to the corresponding functions and data types in the netCDF C library.
Read NetCDF Data Directly from Remote Locations
Read netCDF data directly from remote locations without local download.

Troubleshooting

Resolve Errors Reading OPeNDAP Data

When you have trouble reading OPeNDAP data, consider these factors.

Related Information

NetCDF C Library Documentation