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measures.baseline - Function

1.4.1 define a baseline measure


Description

baseline defines a baseline measure from the CLI. It has to specify a reference code, baseline quantity values (see introduction for the action on a scalar quantity with either a vector or scalar value, and when a vector of quantities is given), and optionally it can specify an offset, which in itself has to be a baseline. Allowable reference codes are ITRF and the direction ones.
Note that additional ones may become available. Check in CASA with:

print "\t----\t baseline Ex 1 \t----"  
print me.listcodes(me.baseline())  
#{’normal’: [’J2000’, ’JMEAN’, ’JTRUE’, ’APP’, ’B1950’, ’BMEAN’, ’BTRUE’,  
# ’GALACTIC’, ’HADEC’, ’AZEL’, ’AZELSW’, ’AZELNE’, ’AZELGEO’, ’AZELSWGEO’,  
# ’AZELNEGEO’, ’JNAT’, ’ECLIPTIC’, ’MECLIPTIC’, ’TECLIPTIC’, ’SUPERGAL’,  
# ’ITRF’, ’TOPO’, ’ICRS’], ’extra’: []}

The baseline quantity values should be either longitude (angle), latitude(angle) and height(length); or x,y,z (length). See quantity for possible angle formats.

Arguments

Inputs

rf

reference code

allowed:

string

Default:

ITRF

v0

longitude or x

allowed:

any

Default:

variant

v1

latitude or y

allowed:

any

Default:

variant

v2

height or z

allowed:

any

Default:

variant

off

optional offset baseline measure

allowed:

record

Default:

Returns
record

Example

 
 
print "\t----\t Ex 2 \t----"  
print me.baseline(’itrf’,’30deg’,’40deg’,’10m’)  
#{’m0’: {’value’: 0.52359877559829882, ’unit’: ’rad’},  
# ’m1’: {’value’: 0.6981317007977319, ’unit’: ’rad’},  
# ’m2’: {’value’: 9.9999999999999982, ’unit’: ’m’},  
# ’refer’: ’ITRF’,  
# ’type’: ’baseline’}  
print me.doframe(me.observatory(’atca’))  
print me.doframe(me.source(’1934-638’))  
print me.doframe(me.epoch(’utc’,qa.unit(’today’)))  
print me.measure(me.baseline(’itrf’,’30deg’,’40deg’,’10m’), ’J2000’)  
#{’m0’: {’value’: 0.58375325605991979, ’unit’: ’rad’},  
# ’m1’: {’value’: 0.69758519780286155, ’unit’: ’rad’},  
# ’m2’: {’value’: 9.9999999999999964, ’unit’: ’m’},  
# ’refer’: ’J2000’,  
# ’type’: ’baseline’}  
 

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