WCS¶
-
class
gwcs.wcs.
WCS
(forward_transform=None, input_frame=u'detector', output_frame=None, name=u'')[source]¶ Bases:
object
Basic WCS class.
Parameters: forward_transform :
Model
or a listThe transform between
input_frame
andoutput_frame
. A list of (frame, transform) tuples whereframe
is the starting frame andtransform
is the transform from this frame to the next one oroutput_frame
. The last tuple is (transform, None), where None indicates the end of the pipeline.input_frame : str,
CoordinateFrame
A coordinates object or a string name.
output_frame : str,
CoordinateFrame
A coordinates object or a string name.
name : str
a name for this WCS
Attributes Summary
available_frames
List all frames in this WCS object. backward_transform
Return the total backward transform if available - from output to input coordinate system. domain
Return the range of acceptable values for each input axis. forward_transform
Return the total forward transform - from input to output coordinate frame. input_frame
Return the input coordinate frame. name
Return the name for this WCS. output_frame
Return the output coordinate frame. pipeline
Return the pipeline structure. unit
The unit of the coordinates in the output coordinate system. Methods Summary
__call__
(*args, **kwargs)Executes the forward transform. footprint
([domain, center])Return the footprint of the observation in world coordinates. get_transform
(from_frame, to_frame)Return a transform between two coordinate frames. insert_transform
(frame, transform[, after])Insert a transform before (default) or after a coordinate frame. invert
(*args, **kwargs)Invert coordnates. set_transform
(from_frame, to_frame, transform)Set/replace the transform between two coordinate frames. transform
(from_frame, to_frame, *args, **kwargs)Transform positions between two frames. Attributes Documentation
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available_frames
¶ List all frames in this WCS object.
Returns: available_frames : dict
{frame_name: frame_object or None}
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backward_transform
¶ Return the total backward transform if available - from output to input coordinate system.
Raises: NotImplementedError :
An analytical inverse does not exist.
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domain
¶ Return the range of acceptable values for each input axis.
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forward_transform
¶ Return the total forward transform - from input to output coordinate frame.
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input_frame
¶ Return the input coordinate frame.
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name
¶ Return the name for this WCS.
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output_frame
¶ Return the output coordinate frame.
-
pipeline
¶ Return the pipeline structure.
-
unit
¶ The unit of the coordinates in the output coordinate system.
Methods Documentation
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__call__
(*args, **kwargs)[source]¶ Executes the forward transform.
- args : float or array-like
- Inputs in the input coordinate system, separate inputs for each dimension.
- output : str
- One of [“numericals”, “numericals_plus”]
If “numericals_plus” - returns a
SkyCoord
orQuantity
object.
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footprint
(domain=None, center=True)[source]¶ Return the footprint of the observation in world coordinates.
Parameters: domain : slice or tuple of floats: (start, stop, step) or (start, stop) or (stop,)
size of image
center : bool
If
True
use the center of the pixel, otherwise use the corner.Returns: coord : (4, 2) array of (x, y) coordinates.
The order is counter-clockwise starting with the bottom left corner.
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get_transform
(from_frame, to_frame)[source]¶ Return a transform between two coordinate frames.
Parameters: from_frame : str or
CoordinateFrame
Initial coordinate frame name of object.
to_frame : str, or instance of
CoordinateFrame
End coordinate frame name or object.
Returns: transform :
Model
Transform between two frames.
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insert_transform
(frame, transform, after=False)[source]¶ Insert a transform before (default) or after a coordinate frame.
Append (or prepend) a transform to the transform connected to frame.
Parameters: frame : str or
CoordinateFrame
Coordinate frame which sets the point of insertion.
transform :
Model
New transform to be inserted in the pipeline
after : bool
If True, the new transform is inserted in the pipeline immediately after
frame
.
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invert
(*args, **kwargs)[source]¶ Invert coordnates.
The analytical inverse of the forward transform is used, if available. If not an iterative method is used.
Parameters: args : float, array like,
SkyCoord
orUnit
coordinates to be inverted
kwargs : dict
keyword arguments to be passed to the iterative invert method.
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set_transform
(from_frame, to_frame, transform)[source]¶ Set/replace the transform between two coordinate frames.
Parameters: from_frame : str or
CoordinateFrame
Initial coordinate frame.
to_frame : str, or instance of
CoordinateFrame
End coordinate frame.
transform :
Model
Transform between
from_frame
andto_frame
.
-
transform
(from_frame, to_frame, *args, **kwargs)[source]¶ Transform positions between two frames.
Parameters: from_frame : str or
CoordinateFrame
Initial coordinate frame.
to_frame : str, or instance of
CoordinateFrame
Coordinate frame into which to transform.
args : float
input coordinates to transform
args : float or array-like
Inputs in
from_frame
, separate inputs for each dimension.output : str
One of [“numericals”, “numericals_plus”] If “numericals_plus” - returns a
SkyCoord
orQuantity
object.
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