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coordsys.topixel - Function

1.1.3 Convert from absolute world to pixel coordinate


Description

This function converts between world (physical) coordinate and absolute pixel coordinate (0-rel).

The world coordinate can be provided in one of four formats via the argument world. These match the output formats of function toworld.

If you supply fewer world values than there are axes in the Coordinate System, your coordinate vector will be padded out with the reference value for the missing axes. Excess values will be silently ignored.

You may supply the world coordinate in all of the formats described in the formatting discussion.

Arguments

Inputs

value

Absolute world coordinate

allowed:

any

Default:

variant

Returns
record

Example

 
 
"""  
#  
print "\t----\t topixel Ex 1 \t----"  
csys = cs.newcoordsys(direction=True, spectral=True, stokes="I V", linear=2)  
w = csys.toworld([-2,2,1,2,23,24], ’n’)  
print csys.topixel(w)  
#{’ar_type’: ’absolute’, ’pw_type’: ’pixel’,  
# ’numeric’: array([ -2.,   2.,   1.,   2.,  23.,  24.])}  
w = csys.toworld([-2,2,1,2,23,24], ’q’)  
print csys.topixel(w)  
#{’ar_type’: ’absolute’, ’pw_type’: ’pixel’,  
# ’numeric’: array([ -2.,   2.,   1.,   2.,  23.,  24.])}  
w = csys.toworld([-2,2,1,2,23,24], ’m’)  
print csys.topixel(w)  
#{’ar_type’: ’absolute’, ’pw_type’: ’pixel’,  
# ’numeric’: array([ -2.,   2.,   1.,   2.,  23.,  24.])}  
w = csys.toworld([-2,2,1,2,23,24], ’s’)  
print cs.topixel(w)  
#{’ar_type’: ’absolute’, ’pw_type’: ’pixel’,  
# ’numeric’: array([ -2.,   2.,   1.,   2.,  23.,  24.])}  
w = csys.toworld([-2,2,1,2,23,24], ’mnq’)  
print cs.topixel(w)  
#{’ar_type’: ’absolute’, ’pw_type’: ’pixel’,  
# ’numeric’: array([ -2.,   2.,   1.,   2.,  23.,  24.])}  
#  
"""  
 

Example

 
 
"""  
#  
print "\t----\t topixel Ex 2 \t----"  
csys = cs.newcoordsys (stokes="I V", linear=2)  
print csys.toworld([0,1,2], ’s’)  
#{’ar_type’: ’absolute’, ’pw_type’: ’world’,  
# ’string’: array([’I’, ’1.00000000e+00 km’, ’2.00000000e+00 km’],  
#  dtype=’|S18’)}  
print csys.toworld([0,1,2], ’m’)  
#{’ar_type’: ’absolute’, ’pw_type’: ’world’,  
# ’measure’: {’stokes’: ’I’, ’linear’: {’*1’: {’value’: 1.0, ’unit’: ’km’},  
# ’*2’: {’value’: 2.0, ’unit’: ’km’}}}}  
print csys.toworld([0,1,2], ’q’)  
#{’ar_type’: ’absolute’, ’pw_type’: ’world’,  
# ’quantity’: {’*1’: {’value’: 1.0, ’unit’: ’’},  
# ’*2’: {’value’: 1.0, ’unit’: ’km’}, ’*3’: {’value’: 2.0, ’unit’: ’km’}}}  
#  
"""  
 

Example

 
 
"""  
#  
print "\t----\t topixel Ex 3 \t----"  
csys = cs.newcoordsys (spectral=True, linear=1)  
print csys.toworld([0,1,2], ’q’)  
#{’ar_type’: ’absolute’, ’pw_type’: ’world’,  
# ’quantity’: {’*1’: {’value’: 1415000000.0, ’unit’: ’Hz’},  
# ’*2’: {’value’: 1.0, ’unit’: ’km’}}}  
#  
"""  
 

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