FITS Files

Flexible Image Transport System

Flexible Image Transport System (FITS) is an open standard defining a digital file format useful for storage, transmission, and processing of data, formatted as multidimensional arrays or tables. You can interact with FITS files in two ways:

The MATLAB^® high-level FITS functions provide a simplified programmatic interface for reading data from FITS files and writing data from the MATLAB workspace to FITS files.
The MATLAB low-level FITS functions provide finer control over the reading and writing process of FITS files by providing access to more than 50 functions in the CFITSIO C library. To use these functions in MATLAB, prefix the function name with the matlab.io.fits namespace path, or use the import function to add the namespace to the current import list prior to calling the function. For example:
```
import matlab.io.*;
fptr = fits.openFile("tst0012.fits");
```
To use the MATLAB low-level FITS functions, you must be familiar with CFITSIO C API programming concepts, described at https://fits.gsfc.nasa.gov/.

MATLAB uses FITS C library version 4.1.0.

Functions

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High-Level Functions for FITS Files

`fitsdisp`	Display FITS metadata
`fitsinfo`	Information about FITS file
`fitsread`	Read data from FITS file
`fitswrite`	Write image to FITS file

Low-Level Functions for FITS Files

File Access

`closeFile`	Close FITS file
`createFile`	Create FITS file
`deleteFile`	Delete FITS file
`fileMode`	Get I/O mode of FITS file
`fileName`	Get name of FITS file
`openDiskFile`	Open FITS file
`openFile`	Open FITS file (extended-filename syntax)

Image Manipulation

`createImg`	Create FITS image
`getImgSize`	Get size of FITS image
`getImgType`	Get data type of FITS image
`insertImg`	Insert FITS image after current image
`readImg`	Read FITS image data
`setBscale`	Reset FITS image scaling
`writeImg`	Write to FITS image

Keywords

`deleteKey`	Delete key by name
`deleteRecord`	Delete key by record number
`getHdrSpace`	Get number of keywords in header
`readCard`	Read header record of keyword
`readKey`	Read keyword
`readKeyCmplx`	Read keyword as complex scalar value
`readKeyDbl`	Read keyword as double precision value
`readKeyLongLong`	Read keyword as 64-bit integer value
`readKeyLongStr`	Read keyword as long string value
`readKeyUnit`	Read physical units string from keyword
`readRecord`	Read header record specified by number
`writeComment`	Write or append COMMENT keyword to CHU
`writeDate`	Write DATE keyword to CHU
`writeHistory`	Write or append HISTORY keyword to CHU
`writeKey`	Update or add new keyword into current HDU
`writeKeyUnit`	Write physical units string

Header Data Unit (HDU) Access

`copyHDU`	Copy current HDU from one file to another
`deleteHDU`	Delete current HDU in FITS file
`getHDUnum`	Get number of current HDU in FITS file
`getHDUtype`	Get type of current HDU in FITS file
`getNumHDUs`	Get total number of HDUs in FITS file
`movAbsHDU`	Move to absolute HDU number
`movNamHDU`	Move to first HDU having specific type and keyword values
`movRelHDU`	Move relative number of HDUs from current HDU
`writeChecksum`	Compute and write checksum for current HDU

Image Compression

`imgCompress`	Compress HDU from one file into another
`isCompressedImg`	Determine if current image is compressed
`setCompressionType`	Set image compression type
`setHCompScale`	Set scale parameter for HCOMPRESS algorithm
`setHCompSmooth`	Set smoothing for images compressed with HCOMPRESS
`setTileDim`	Set tile dimensions

ASCII and Binary Tables

`createTbl`	Create new ASCII or binary table extension
`insertCol`	Insert column into table
`insertRows`	Insert rows into table
`insertATbl`	Insert ASCII table after current HDU
`insertBTbl`	Insert binary table after current HDU
`deleteCol`	Delete column from table
`deleteRows`	Delete rows from table
`getAColParms`	Get ASCII table information
`getBColParms`	Get binary table information
`getColName`	Get table column name
`getColType`	Get scaled column data type, repeat value, width
`getEqColType`	Get column data type, repeat value, width
`getNumCols`	Get number of columns in table
`getNumRows`	Get number of rows in table
`readATblHdr`	Read header information from current ASCII table
`readBTblHdr`	Read header information from current binary table
`readCol`	Read rows of ASCII or binary table column
`setTscale`	Reset image scaling
`writeCol`	Write elements into ASCII or binary table column

Utilities

`getConstantValue`	Get numeric value of named constant
`getVersion`	Get revision number of the CFITSIO library
`getOpenFiles`	Get list of open FITS files

Topics

Importing Flexible Image Transport System (FITS) Files
Import a FITS file using high-level functions.

Related Information

CFITSIO C Library Documentation