1.1.1.0 image.summary

NRAO Home > CASA > CasaDocument

image.summary - Function

1.1.1 Summarize basic information about the image
Description

This function summarizes miscellaneous information such as shape, Coordinate System, restoring beams, and masks.

If called without any arguments, this function displays a summary of the image header to the logger; where appropriate, values will be formatted nicely (e.g. HH:MM:SS.SS for the reference value of RA axes).

For spectral axes, the information is listed as a velocity as well as a frequency. The argument doppler allows you to specify what velocity doppler convention it is listed in. You can choose from radio, optical and true. Alternative names are z for optical, and beta or relativistic for true. The default is radio. The definitions are

radio: 1 - F
optical: -1 + 1∕F
true: (1 - F²)∕(1 + F²)

where F = ν∕ν₀ and ν₀ is the rest frequency. If the rest frequency has not been set in your image, you can set it via a Coordsys tool with the function setrestfrequency.

If the output of summary is saved to a variable, then the header field (for instance, mysummary[’header’]) has the following fields filled in:

ndim: Dimension of the image.
shape: Length of each axis in the image.
tileshape: Shape of the chunk which is most efficient for I/O.
axisnames: Name of each axis.
refpix: Reference pixel for each axis (0-relative)
refval: Reference value for each axis.
incr: Increment for each axis.
axisunits: Unit name for each axis.
unit: Brightness units for the pixels.
hasmask: True if the image has a mask.
defaultmask: The name of the mask which is applied by default.
masks: The names of all the masks stored in this image.
restoringbeam: The restoring beam if present.
imagetype: The image type.

If you set list=F, then the summary will not be written to the logger. The return value of the function, in the header field is a vector string containing the formatted output that would normally have gone to the logger.

Arguments


Outputs
header	Header information
	allowed:	any
	Default:	record
Inputs
doppler	If there is a spectral axis, list velocity too, with this doppler definition
	allowed:	string
	Default:	RADIO
list	List the summary to the logger
	allowed:	bool
	Default:	true
pixelorder	List axis descriptors in pixel or world axis order
	allowed:	bool
	Default:	true

Returns
stringArray

Example

"""
#
print "\t----\t summary Ex 1 \t----"
ia.maketestimage(’myim1’, overwrite=true)
ia.summary()                 # summarize to logging only
s = ia.summary(list=F)       # store header in record
if s[’header’][’ndim’] == 2: # program using header values
  print s[’header’][’axisnames’]
ia.close()
#
"""

[next] [prev] [prev-tail] [front] [up]

Please send any comments or questions about CASA or AIPS++ to aips2-requests@nrao.edu

This code is available under the terms of the GNU General Public Lincense