Fichiers CDF

Common Data Format

Common Data Format (CDF) désigne un format de données autodescriptif permettant de stocker des données scalaires et multidimensionnelles indépendamment de la plateforme et de la discipline. Il existe deux façons d’interagir avec les fichiers CDF :

Les fonctions MATLAB^® CDF de haut niveau offrent une interface de programmation simplifiée pour la lecture des données de fichiers CDF.
Les fonctions MATLAB CDF de bas niveau permettent de mieux contrôler le processus de lecture et d’écriture des fichiers CDF en proposant un accès à plus de 90 fonctions dans la librairie C CDF. Pour exporter des données vers un fichier CDF, vous devez utiliser les fonctions de bas niveau. Pour utiliser ces fonctions dans MATLAB, ajoutez le chemin du namespace cdflib comme préfixe au nom de la fonction. Par exemple :
```
cdfid = cdflib.open("example.cdf");
```
L’utilisation des fonctions MATLAB CDF de bas niveau nécessite une bonne connaissance des concepts de programmation de l’API C CDF, lesquels sont décrits sur https://cdf.gsfc.nasa.gov/.

MATLAB utilise la librairie C CDF version 3.8.1.

Fonctions

développer tout

Fonctions de haut niveau pour les fichiers CDF

`cdfinfo`	Information about Common Data Format (CDF) file
`cdfread`	Read data from Common Data Format (CDF) file

Fonctions de bas niveau pour les fichiers CDF

Informations sur les bibliothèques

`cdflib.getConstantNames`	Names of Common Data Format (CDF) library constants
`cdflib.getConstantValue`	Numeric value corresponding to Common Data Format (CDF) library constant
`cdflib.getFileBackward`	Return backward compatibility mode
`cdflib.getLibraryCopyright`	Copyright notice of Common Data Format (CDF) library
`cdflib.getLibraryVersion`	Library version and release information
`cdflib.getValidate`	Library validation mode
`cdflib.setFileBackward`	Specify backward compatibility mode
`cdflib.setValidate`	Specify library validation mode

Opérations sur les fichiers

`cdflib.close`	Close Common Data Format (CDF) file
`cdflib.delete`	Delete Common Data Format (CDF) file
`cdflib.open`	Open Common Data Format (CDF) file

Opérations de lecture de fichier

`cdflib.getCacheSize`	Number of cache buffers
`cdflib.getChecksum`	Checksum mode
`cdflib.getCompression`	Compression settings
`cdflib.getCompressionCacheSize`	Number of compression cache buffers
`cdflib.getCopyright`	Copyright notice in Common Data Format (CDF) file
`cdflib.getFormat`	Format of Common Data Format (CDF) file
`cdflib.getMajority`	Majority of variables
`cdflib.getName`	Name of Common Data Format (CDF) file
`cdflib.getReadOnlyMode`	Read-only mode
`cdflib.getStageCacheSize`	Number of cache buffers for staging
`cdflib.getVersion`	Common Data Format (CDF) library version and release information
`cdflib.inquire`	Information about Common Data Format (CDF) file

Opérations d’écriture de fichier

`cdflib.create`	Create Common Data Format (CDF) file
`cdflib.setCacheSize`	Specify number of dotCDF cache buffers
`cdflib.setChecksum`	Specify checksum mode
`cdflib.setCompression`	Specify compression settings
`cdflib.setCompressionCacheSize`	Specify number of compression cache buffers
`cdflib.setFormat`	Specify format of Common Data Format (CDF) file
`cdflib.setMajority`	Specify majority of variables
`cdflib.setReadOnlyMode`	Specify read-only mode
`cdflib.setStageCacheSize`	Specify number of staging cache buffers for Common Data Format (CDF) file

Lire des variables

`cdflib.getVarAllocRecords`	Number of records allocated for variable
`cdflib.getVarBlockingFactor`	Blocking factor for variable
`cdflib.getVarCacheSize`	Number of multifile cache buffers
`cdflib.getVarCompression`	Information about compression used by variable
`cdflib.getVarData`	Single value from record in variable
`cdflib.getVarMaxAllocRecNum`	Maximum allocated record number for variable
`cdflib.getVarMaxWrittenRecNum`	Maximum written record number for variable
`cdflib.getVarName`	Variable name, given variable number
`cdflib.getVarNum`	Variable number, given variable name
`cdflib.getVarNumRecsWritten`	Number of records written to variable
`cdflib.getVarPadValue`	Pad value for variable
`cdflib.getVarRecordData`	Entire record for variable
`cdflib.getVarReservePercent`	Compression reserve percentage for variable
`cdflib.getVarsMaxWrittenRecNum`	Maximum written record number for CDF file
`cdflib.getVarSparseRecords`	Information about how variable handles sparse records
`cdflib.hyperGetVarData`	Read hyperslab of data from variable
`cdflib.inquireVar`	Information about variable

Écrire des variables

`cdflib.closeVar`	Close specified variable from multifile format Common Data Format (CDF) file
`cdflib.createVar`	Create new variable
`cdflib.deleteVar`	Delete variable
`cdflib.deleteVarRecords`	Delete range of records from variable
`cdflib.hyperPutVarData`	Write hyperslab of data to variable
`cdflib.putVarData`	Write single value to variable
`cdflib.putVarRecordData`	Write entire record to variable
`cdflib.renameVar`	Change name of variable
`cdflib.setVarAllocBlockRecords`	Specify range of records to be allocated for variable
`cdflib.setVarBlockingFactor`	Specify blocking factor for variable
`cdflib.setVarCacheSize`	Specify number of multifile cache buffers for variable
`cdflib.setVarCompression`	Specify compression settings used with variable
`cdflib.setVarInitialRecs`	Specify initial number of records written to variable
`cdflib.setVarPadValue`	Specify pad value used with variable
`cdflib.setVarReservePercent`	Specify reserve percentage for variable
`cdflib.setVarsCacheSize`	Specify number of cache buffers used for all variables
`cdflib.setVarSparseRecords`	Specify how variable handles sparse records

Lire des attributs

`cdflib.getAttrEntry`	Value of entry in attribute with variable scope
`cdflib.getAttrgEntry`	Value of entry in global attribute
`cdflib.getAttrMaxEntry`	Number of last entry for variable attribute
`cdflib.getAttrMaxgEntry`	Number of last entry for global attribute
`cdflib.getAttrName`	Attribute name, given attribute number
`cdflib.getAttrNum`	Attribute number, given attribute name
`cdflib.getAttrScope`	Scope of attribute
`cdflib.getNumAttrEntries`	Number of entries for attribute with variable scope
`cdflib.getNumAttrgEntries`	Number of entries for attribute with global scope
`cdflib.getNumAttributes`	Number of attributes with variable scope
`cdflib.getNumgAttributes`	Number of attributes with global scope
`cdflib.inquireAttr`	Information about attribute
`cdflib.inquireAttrEntry`	Information about entry in attribute with variable scope
`cdflib.inquireAttrgEntry`	Information about entry in attribute with global scope

Écrire des attributs

`cdflib.createAttr`	Create attribute
`cdflib.deleteAttr`	Delete attribute
`cdflib.deleteAttrEntry`	Delete entry from attribute with variable scope
`cdflib.deleteAttrgEntry`	Delete entry from attribute with global scope
`cdflib.putAttrEntry`	Write value to entry in attribute with variable scope
`cdflib.putAttrgEntry`	Write value to entry in attribute with global scope
`cdflib.renameAttr`	Change name of attribute

Fonctions utilitaires

`cdflib.breakdownTT2000`	Convert `CDF_TIME_TT2000` timestamp to time components (depuis R2022b)
`cdflib.computeEpoch`	Convert time value to `CDF_EPOCH` value
`cdflib.computeEpoch16`	Convert time value to `CDF_EPOCH16` value
`cdflib.computeTT2000`	Convert time components to `CDF_TIME_TT2000` timestamp (depuis R2022b)
`cdflib.epoch16Breakdown`	Convert `CDF_EPOCH16` value to time value
`cdflib.epochBreakdown`	Convert `CDF_EPOCH` value to time value

Rubriques

Import CDF Files Using High-Level Functions
Use high-level functions to import a CDF file.
Import CDF Files Using Low-Level Functions
Use low-level functions to read data from a CDF file.
Represent CDF Time Values
Extract date and time information from CDF datasets.
Export to CDF Files
Use low-level functions to write data to a CDF file.

Informations connexes

Documentation sur la librairie C CDF