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ISIS Documentation

isis2fits

Exports a cube to fits format

This program will export an Isis cube to fits format. It is recommended that the image be output in 32-bit per pixel format. The user may also choose to output into an 8-bit, 16-bit unsigned, or 16-bit signed image but in order to ensure that the range of pixels is not truncated when going to a less precise format, it is recommended that the output file be stretched using a linear stretch. Special pixels are mapped in the following manner; Low Saturation values and Null are made black and High Saturation values are made white.

Categories

Related Objects and Documents

Applications

History

Drew Davidson2005-06-01 Original version
Drew Davidson2005-06-15 Added code to export multiple bands
Jeff Anderson2006-05-15 Added minpercent and maxpercent options
Steven Lambright2007-06-15 Updated documentation to follow current standards
Steven Lambright2008-05-12 Removed references to CubeInfo
Mackenzie Boyd2009-10-29 Made SkyMap and All options work, added more keywords to ALL option, removed unsigned 16 bit option, made file total come out to a sum evenly divisible by 2880 as specified in the standard.

Parameters

Files

Use this parameter to select the filename and band to export. For example, file.cub+5 will select band 5
Type cube
File Mode input
Filter *.cub

Use this parameter to specify the name of the output fits file. If you do not include an extension of ".fits" it will be added automatically.
Type filename
File Mode output

Output Data Type

Bit type of output: 8 bit (0=black, 255=white) 16 bit unsigned (0=black, 65535=white) 16 bit signed (-32767=black, 32768=white) 32 bit (1.17549435e-38=black, 3.40282347e+38=white)
Type string
Default 32BIT
Option List:
Option Brief Description
8BIT8 bit data Pixels are in 8-bit data range (0 to 255).
16BIT 16 bit data Pixels are in 16 bit signed data range (-32768 to 32767)
32BIT 32 bit data Pixels are in the 32 bit floating point data range (-3.40282347e+38 to 3.40282347e+38)

Exclusions

  • STRETCH
  • MINPERCENT
  • MAXPERCENT

Stretch Options

This parameter is used to select one of four ways to stretch (or map) output pixels. They are NONE, LINEAR, or MANUAL. It is recommended that output data that is less precise than the input data from whence it came (i.e. 32-bit data being output as 8-bit data) be stretched.
Type string
Default LINEAR
Option List:
Option Brief Description
NONE No stretch No stretch is performed.

Exclusions

  • MINIMUM
  • MAXIMUM
  • MINPERCENT
  • MAXPERCENT
LINEAR Linear stretch A minimum and maximum are automatically computed based on the statistics of the selected band. A histogram of the band is used to pick the minimum at 0.5% of the data and the maximum at 99.5% of the data. Input pixels less than or equal to the minimum are stretched to black while pixels greater than the or equal to the maximum are stretched to white. A linear mapping occurs between the minimum and maximum.

Exclusions

  • MINIMUM
  • MAXIMUM

Inclusions

  • MINPERCENT
  • MAXPERCENT
MANUAL Manual stretch This option allows you to pick your own stretch. You must enter a value for MINIMUM and MAXIMUM;

Exclusions

  • MINPERCENT
  • MAXPERCENT

Inclusions

  • MINIMUM
  • MAXIMUM

The minimum input pixel value which will be mapped to black.
Type double
Less Than MAXIMUM

The maximum input pixel value which will be mapped to white.
Type double
Greater Than MINIMUM

The percentage of data in the histogram used to compute the minimum pixel value in the stretch.
Type double
Default 0.5
Less Than MAXPERCENT

The percentage of data in the histogram used to compute the maximum pixel value in the stretch.
Type double
Default 99.5
Greater Than MINPERCENT

Header Information

This parameter is used to determine how much information will appear in the FITS header. Minimally, the header will include the information necessary to conform to the FITS header, which conveniently also allows it to be read by a FITS file reader. This is automatically read from the cube label.
Type string
Default NOMINAL
Option List:
Option Brief Description
NOMINALNominal Fits header This option will include only minimal information in the fits header. This includes the bits per pixel, the number of samples in the cube, the number of lines in the cube, and the core base and multiplier for DN values. Though this will transfer information to the fits standard quickly, it will essentially strip the cube of all information other than raw pixel values.
SKYInclude information from a Skymap in the fits header This option will include, in addition to everything in the nominal option, the OBJCTRA and OBJCTDEC fits keywords, which signify the right ascension and the declination, respectively.
ALLInclude as much of the cube label as possible This option will include as many keywords from the label as are supported by the fits standard, including the information from the skymap.