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coordsys.convert - Function

1.1.3 Convert a numeric mixed coordinate


Description

This function converts between mixed pixel/world/abs/rel numeric coordinates. The input and output coordinates are specified via a numeric vector giving coordinate values, a string vector giving units, a boolean vector specifying whether the coordinate is absolute or relative (to the reference pixel) and doppler strings specifying the doppler convention for velocities.

The units string may include pix for pixel coordinates and velocity units (i.e. any unit consistent with m/s).

The allowed doppler strings and definition are described in function summary.

The shape argument is optional. If your Coordinate System is from an image, then assign the image shape to this argument. It is used only when making mixed (pixel/world) conversions for Direction Coordinates to resolve ambiguity.

The example clarifies the use of this function.

Arguments





Inputs

coordin

Input coordinate, as a numeric vector

allowed:

doubleArray

Default:

absin

Are input coordinate elements absolute ?

allowed:

boolArray

Default:

true

dopplerin

Input doppler type for velocities

allowed:

string

Default:

radio

unitsin

Input units, string vector

allowed:

stringArray

Default:

Native

absout

Are output coordinate elements absolute ?

allowed:

boolArray

Default:

true

dopplerout

Output doppler type for velocities

allowed:

string

Default:

radio

unitsout

Output units

allowed:

stringArray

Default:

Native

shape

Image shape, integer vector

allowed:

intArray

Default:

-1

Returns
doubleArray

Example

 
In this example we convert from a vector of absolute pixels  
to a mixture of pixel/world and abs/rel.  
 
"""  
#  
print "\t----\t convert Ex 1 \t----"  
csys=cs.newcoordsys(direction=T, spectral=T)    # 3 axes  
cout=csys.convert(coordin=[10,20,30],absin=[T,T,T],  
                  unitsin=["pix","pix","pix"],  
                  absout=[T,F,T], dopplerout=’optical’,  
                  unitsout=["pix","arcsec","km/s"])  
print cout  
#[10.0, 1140.0058038878046, 1139.1354056919731]  
#  
"""  
 

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