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coordsys.summary - Function

1.1.3 Summarize basic information about the Coordinate System


Description

This function summarizes the information contained in the Coordinate System.

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

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 with the function setrestfrequency.

These velocity definitions are provided by the measures system via the Doppler measure (see example).

If you set list=F, then the summary will not be written to the global logger. However, the return value will be a vector of strings holding the summary information, one string per line of the summary.

For direction and spectral coordinates, the reference frame (e.g. J2000 or LSRK) is also listed. Along side this, in parentheses, will be the conversion reference frame as well (if it is different from the native reference frame). See function setconversion to see what this means.

Arguments





Inputs

doppler

List velocity information with this doppler definition

allowed:

string

Default:

RADIO

list

List to global logger

allowed:

bool

Default:

true

Returns
stringArray

Example

 
 
"""  
#  
print "\t----\t summary Ex 1 \t----"  
d = me.doppler(’beta’)  
print me.listcodes(d)  
#[normal=RADIO Z RATIO BETA GAMMA OPTICAL TRUE RELATIVISTIC, extra=]  
csys = cs.newcoordsys(direction=T, spectral=T)  
print csys.summary(list=F)  
#  
#Direction reference : J2000  
#Spectral  reference : LSRK  
#Velocity  type      : RADIO  
#Rest frequency      : 1.42041e+09 Hz  
#Telescope           : ATCA  
#Observer            : Karl Jansky  
#Date observation    : 2007/07/14/04:49:31  
#  
#Axis Coord Type      Name             Proj   Coord value at pixel    Coord incr Units  
#-------------------------------------------------------------------------------------  
#0    0     Direction Right Ascension   SIN  00:00:00.000     0.00 -6.000000e+01 arcsec  
#1    0     Direction Declination       SIN +00.00.00.000     0.00  6.000000e+01 arcsec  
#2    1     Spectral  Frequency                 1.415e+09     0.00  1.000000e+03 Hz  
#                     Velocity                    1140.94     0.00 -2.110611e-01 km/s  
#  
#  
"""  
 

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