ExtraCoords#
- class ndcube.ExtraCoords(ndcube=None)[source]#
- Bases: - ExtraCoordsABC- A representation of additional world coordinates associated with pixel axes. - ExtraCoords can be initialised by either specifying a - BaseLowLevelWCSobject and a- mapping, or it can be built up by specifying one or more lookup tables.- Parameters:
- wcs – The WCS specifying the extra coordinates. 
- mapping – The mapping between the array dimensions and pixel dimensions in the extra coords object. This is an iterable of - (array_dimension, pixel_dimension)pairs of length equal to the number of pixel dimensions in the extra coords.
 
 - Attributes Summary - Produce a WCS that describes the associated NDCube with just the extra coords. - Return an APE-14 like representation of any sliced out world dimensions. - Return True if no extra coords present, else return False. - The mapping between the array dimensions and pixel dimensions. - A WCS object representing the world coordinates described by this - ExtraCoords.- Methods Summary - add(name, array_dimension, lookup_table[, ...])- Add a coordinate to this - ExtraCoordsbased on a lookup table.- from_lookup_tables(names, pixel_dimensions, ...)- Construct a new ExtraCoords instance from lookup tables. - keys()- The world axis names for all the coordinates in the extra coords. - resample(factor[, offset, ndcube])- Resample all extra coords by given factors in array-index-space. - Attributes Documentation - cube_wcs#
- Produce a WCS that describes the associated NDCube with just the extra coords. - For NDCube pixel axes without any extra coord, dummy axes are inserted. 
 - dropped_world_dimensions#
- Return an APE-14 like representation of any sliced out world dimensions. 
 - is_empty#
 - mapping#
 - wcs#
 - Methods Documentation - add(
- name,
- array_dimension,
- lookup_table,
- physical_types=None,
- **kwargs,
- Add a coordinate to this - ExtraCoordsbased on a lookup table.- Parameters:
- name ( - stror sequence of- str) – The name(s) for these world coordinate(s).
- array_dimension ( - intor- tupleof- int) – The array dimension(s), to which this lookup table corresponds.
- lookup_table ( - objector sequence of- object) – The lookup table. A- BaseTableCoordinatesubclass or anything that can instantiate one, i.e. currently a- Time,- SkyCoord, or a (sequence of)- Quantity.
- physical_types ( - stror iterable of- str, optional) – Descriptor(s) of the <dimensions and physical types associated with each axis; length must match the number of dimensions in- lookup_table.
 
 
 - classmethod from_lookup_tables(
- names,
- pixel_dimensions,
- lookup_tables,
- physical_types=None,
- Construct a new ExtraCoords instance from lookup tables. - This is a convenience wrapper around - ndcube.ExtraCoords.addwhich does not expose all the options available in that method.- Parameters:
- pixel_dimensions ( - tupleof- int) – The pixel dimensions (in the array) to which the- lookup_tablesapply. Must be the same length as- lookup_tables.
- lookup_tables (iterable of - object) – The lookup tables which specify the world coordinates for the- pixel_dimensions. Must be- BaseTableCoordinatesubclass instances or objects from which to instantiate them (see- ndcube.ExtraCoords.add).
- physical_types (sequence of - stror of sequences of- str, optional) – Descriptors of the Shape and physical types associated with each axis in the tables. Must be the same length as- lookup_tables; and length of each element must match the number of dimensions in corresponding- lookup_tables[i]. Defaults to- None.
 
- Returns:
 
 - resample(factor, offset=0, ndcube=None, **kwargs)[source]#
- Resample all extra coords by given factors in array-index-space. - One resample factor must be supplied for each array axis in array-axis order. - Parameters:
- factor ( - int,- float, or iterable thereof.) – The factor by which each array axis is resampled. If scalar, same factor is applied to all axes. Otherwise a factor for each axis must be provided.
- offset ( - int,- float, or iterable therefore.) – The location on the underlying grid which corresponds to the zeroth element after resampling. If iterable, must have an entry for each dimension. If a scalar, the grid will be shifted by the same amount in all dimensions.
- ndcube ( - NDCube) – The NDCube instance with which the output ExtraCoords object is associated.
- kwargs – All remaining kwargs are passed to - numpy.interp.
 
- Returns:
- new_ec ( - ExtraCoords) – A new ExtraCoords object holding the interpolated coords.
 
 
