SlicedLowLevelWCS¶

class
astropy.wcs.wcsapi.
SlicedLowLevelWCS
(wcs, slices)[source]¶ Bases:
astropy.wcs.wcsapi.BaseWCSWrapper
A Low Level WCS wrapper which applies an array slice to a WCS.
This class does not modify the underlying WCS object and can therefore drop coupled dimensions as it stores which pixel and world dimensions have been sliced out (or modified) in the underlying WCS and returns the modified results on all the Low Level WCS methods.
 Parameters
 wcs
BaseLowLevelWCS
The WCS to slice.
 slices
slice
ortuple
orint
A valid array slice to apply to the WCS.
 wcs
Attributes Summary
The shape of the data that the WCS applies to as a tuple of length
pixel_n_dim
in(row, column)
order (the convention for arrays in Python).Returns an (
world_n_dim
,pixel_n_dim
) matrix that indicates using booleans whether a given world coordinate depends on a given pixel coordinate.Information describing the dropped world dimensions.
An iterable of strings describing the name for each pixel axis.
The bounds (in pixel coordinates) inside which the WCS is defined, as a list with
pixel_n_dim
(min, max)
tuples.The number of axes in the pixel coordinate system.
The shape of the data that the WCS applies to as a tuple of length
pixel_n_dim
in(x, y)
order (where for an image,x
is the horizontal coordinate andy
is the vertical coordinate).Indicates whether Python objects are given in serialized form or as actual Python objects.
An iterable of strings describing the name for each world axis.
A dictionary giving information on constructing highlevel objects for the world coordinates.
A list with
world_n_dim
elements giving information on constructing highlevel objects for the world coordinates.An iterable of strings describing the physical type for each world axis.
An iterable of strings given the units of the world coordinates for each axis.
The number of axes in the world coordinate system.
Methods Summary
array_index_to_world_values
(*index_arrays)Convert array indices to world coordinates.
pixel_to_world_values
(*pixel_arrays)Convert pixel coordinates to world coordinates.
world_to_array_index_values
(*world_arrays)Convert world coordinates to array indices.
world_to_pixel_values
(*world_arrays)Convert world coordinates to pixel coordinates.
Attributes Documentation

array_shape
¶

axis_correlation_matrix
¶

dropped_world_dimensions
¶ Information describing the dropped world dimensions.

pixel_axis_names
¶

pixel_bounds
¶

pixel_n_dim
¶

pixel_shape
¶

serialized_classes
¶

world_axis_names
¶

world_axis_object_classes
¶

world_axis_object_components
¶

world_axis_physical_types
¶

world_axis_units
¶

world_n_dim
¶
Methods Documentation

array_index_to_world_values
(*index_arrays)¶ Convert array indices to world coordinates.
This is the same as
pixel_to_world_values
except that the indices should be given in(i, j)
order, where for an imagei
is the row andj
is the column (i.e. the opposite order topixel_to_world_values
).If
world_n_dim
is1
, this method returns a single scalar or array, otherwise a tuple of scalars or arrays is returned.

pixel_to_world_values
(*pixel_arrays)[source]¶ Convert pixel coordinates to world coordinates.
This method takes
pixel_n_dim
scalars or arrays as input, and pixel coordinates should be zerobased. Returnsworld_n_dim
scalars or arrays in units given byworld_axis_units
. Note that pixel coordinates are assumed to be 0 at the center of the first pixel in each dimension. If a pixel is in a region where the WCS is not defined, NaN can be returned. The coordinates should be specified in the(x, y)
order, where for an image,x
is the horizontal coordinate andy
is the vertical coordinate.If
world_n_dim
is1
, this method returns a single scalar or array, otherwise a tuple of scalars or arrays is returned.

world_to_array_index_values
(*world_arrays)¶ Convert world coordinates to array indices.
This is the same as
world_to_pixel_values
except that the indices should be returned in(i, j)
order, where for an imagei
is the row andj
is the column (i.e. the opposite order topixel_to_world_values
). The indices should be returned as rounded integers.If
pixel_n_dim
is1
, this method returns a single scalar or array, otherwise a tuple of scalars or arrays is returned.

world_to_pixel_values
(*world_arrays)[source]¶ Convert world coordinates to pixel coordinates.
This method takes
world_n_dim
scalars or arrays as input in units given byworld_axis_units
. Returnspixel_n_dim
scalars or arrays. Note that pixel coordinates are assumed to be 0 at the center of the first pixel in each dimension. If a world coordinate does not have a matching pixel coordinate, NaN can be returned. The coordinates should be returned in the(x, y)
order, where for an image,x
is the horizontal coordinate andy
is the vertical coordinate.If
pixel_n_dim
is1
, this method returns a single scalar or array, otherwise a tuple of scalars or arrays is returned.