1.1.3.0 coordsys.convert

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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=True, spectral=True)    # 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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