healsparse modules¶

HealSparseMap¶

class healsparse.healSparseMap.HealSparseMap(cov_map=None, cov_index_map=None, sparse_map=None, nside_sparse=None, healpix_map=None, nside_coverage=None, primary=None, sentinel=None, nest=True, metadata=None, _is_view=False)[source]¶

Bases: object

Class to define a HealSparseMap

__add__(other)[source]¶

Add a constant.

Cannot be used with recarray maps.

__and__(other)[source]¶

Perform a bitwise and with a constant.

Cannot be used with recarray maps.

__getitem__(key)[source]¶: Get part of a healpix map.

__iadd__(other)[source]¶

Add a constant, in place.

Cannot be used with recarray maps.

__iand__(other)[source]¶

Perform a bitwise and with a constant, in place.

Cannot be used with recarray maps.

__imul__(other)[source]¶

Multiply a constant, in place.

Cannot be used with recarray maps.

__init__(cov_map=None, cov_index_map=None, sparse_map=None, nside_sparse=None, healpix_map=None, nside_coverage=None, primary=None, sentinel=None, nest=True, metadata=None, _is_view=False)[source]¶

Instantiate a HealSparseMap.

Can be created with cov_index_map, sparse_map, and nside_sparse; or with healpix_map, nside_coverage. Also see HealSparseMap.read(), HealSparseMap.make_empty(), HealSparseMap.make_empty_like().

Parameters

cov_map (HealSparseCoverage, optional) – Coverage map object
cov_index_map (np.ndarray, optional) – Coverage index map, will be deprecated
sparse_map (np.ndarray, optional) – Sparse map
nside_sparse (int, optional) – Healpix nside for sparse map
healpix_map (np.ndarray, optional) – Input healpix map to convert to a sparse map
nside_coverage (int, optional) – Healpix nside for coverage map
primary (str, optional) – Primary key for recarray, required if dtype has fields.
sentinel (int or float, optional) – Sentinel value. Default is hp.UNSEEN for floating-point types, and minimum int for int types.
nest (bool, optional) – If input healpix map is in nest format. Default is True.
metadata (dict-like, optional) – Map metadata that can be stored in FITS header format.
_is_view (bool, optional) – This healSparse map is a view into another healsparse map. Not all features will be available. (Internal usage)

Returns

healSparseMap

Return type

HealSparseMap

__ior__(other)[source]¶

Perform a bitwise or with a constant, in place.

Cannot be used with recarray maps.

__ipow__(other)[source]¶

Divide a constant, in place.

Cannot be used with recarray maps.

__isub__(other)[source]¶

Subtract a constant, in place.

Cannot be used with recarray maps.

__itruediv__(other)[source]¶

Divide a constant, in place.

Cannot be used with recarray maps.

__ixor__(other)[source]¶

Perform a bitwise xor with a constant, in place.

Cannot be used with recarray maps.

__mul__(other)[source]¶

Multiply a constant.

Cannot be used with recarray maps.

__or__(other)[source]¶

Perform a bitwise or with a constant.

Cannot be used with recarray maps.

__pow__(other)[source]¶

Raise the map to a power.

Cannot be used with recarray maps.

__repr__()[source]¶: Return repr(self).

__setitem__(key, value)[source]¶: Set part of a healpix map

__str__()[source]¶: Return str(self).

__sub__(other)[source]¶

Subtract a constant.

Cannot be used with recarray maps.

__truediv__(other)[source]¶

Divide a constant.

Cannot be used with recarray maps.

__weakref__¶: list of weak references to the object (if defined)

__xor__(other)[source]¶

Perform a bitwise xor with a constant.

Cannot be used with recarray maps.

apply_mask(mask_map, mask_bits=None, mask_bit_arr=None, in_place=True)[source]¶

Apply an integer mask to the map. All pixels in the integer mask that have any bits in mask_bits set will be zeroed in the output map. The default is that this operation will be done in place, but it may be set to return a copy with a masked map.

Parameters

mask_map (HealSparseMap) – Integer mask to apply to the map.
mask_bits (int, optional) – Bits to be treated as bad in the mask_map. Default is None (all non-zero pixels are masked)
mask_bit_arr (list or np.ndarray, optional) – Array of bit values, used if mask_map is a wide_mask_map.
in_place (bool, optional) – Apply operation in place. Default is True

Returns

masked_map – self if in_place is True, a new copy otherwise

Return type

HealSparseMap

check_bits_pix(pixels, bits, nest=True)[source]¶

Check the bits at the map for a set of pixels.

Parameters

pixel (np.ndarray) – Integer array of healpix pixels.
nest (bool, optional) – Are the pixels in nest scheme? Default is True.
bits (list) – List of bits to check

Returns

bit_flags – Array of np.bool flags on whether any of the input bits were set

Return type

np.ndarray

check_bits_pos(theta_or_ra, phi_or_dec, bits, lonlat=False)[source]¶

Check the bits at the map for an array of positions. Positions may be theta/phi co-latitude and longitude in radians, or longitude and latitude in degrees.

Parameters

theta_or_ra (float, array-like) – Angular coordinates of points on a sphere.
phi_or_dec (float, array-like) – Angular coordinates of points on a sphere.
lonlat (bool, optional) – If True, input angles are longitude and latitude in degrees. Otherwise, they are co-latitude and longitude in radians.
bits (list) – List of bits to check

Returns

bit_flags – Array of np.bool flags on whether any of the input bits were set

Return type

np.ndarray

clear_bits_pix(pixels, bits, nest=True)[source]¶

Clear bits of a wide_mask map.

Parameters

pixels (np.ndarray) – Integer array of sparse_map pixel values
bits (list) – List of bits to clear

static convert_healpix_map(healpix_map, nside_coverage, nest=True, sentinel=- 1.6375e+30)[source]¶

Convert a healpix map to a healsparsemap.

Parameters

healpix_map (np.ndarray) – Numpy array that describes a healpix map.
nside_coverage (int) – Nside for the coverage map to construct
nest (bool, optional) – Is the input map in nest format? Default is True.
sentinel (float, optional) – Sentinel value for null values in the sparse_map. Default is hp.UNSEEN

Returns

cov_map (HealSparseCoverage) – Coverage map with pixel indices
sparse_map (np.ndarray) – Sparse map of input values.

property coverage_map¶

Get the fractional area covered by the sparse map in the resolution of the coverage map

Returns: cov_map – Float array of fractional coverage of each pixel
Return type: np.ndarray

property coverage_mask¶

Get the boolean mask of the coverage map.

Returns: cov_mask – Boolean array of coverage mask.
Return type: np.ndarray

degrade(nside_out, reduction='mean')[source]¶

Reduce the resolution, i.e., increase the pixel size of a given sparse map.

Parameters

nside_out (int) – Output Nside resolution parameter.
reduction (str) – Reduction method (mean, median, std, max, min).

Returns

healSparseMap – New map, at the desired resolution.

Return type

HealSparseMap

property dtype¶: get the dtype of the map

generate_healpix_map(nside=None, reduction='mean', key=None)[source]¶

Generate the associated healpix map

if nside is specified, then reduce to that nside

Parameters

nside (int) – Output nside resolution parameter (should be a multiple of 2). If not specified the output resolution will be equal to the parent’s sparsemap nside_sparse
reduction (str) – If a change in resolution is requested, this controls the method to reduce the map computing the mean, median, std, max or min of the neighboring pixels to compute the “degraded” map.
key (str) – If the parent HealSparseMap contains recarrays, key selects the field that will be transformed into a HEALPix map.

Returns

hp_map – Output HEALPix map with the requested resolution.

Return type

np.ndarray

get_single(key, sentinel=None, copy=False)[source]¶

Get a single healpix map out of a recarray map, with the ability to override a sentinel value.

Parameters

key (str) – Field for the recarray
sentinel (int or float or None, optional) – Override the default sentinel value. Default is None (use default)

get_values_pix(pixels, nest=True, valid_mask=False)[source]¶

Get the map value for a set of pixelx.

Parameters

pixel (np.ndarray) – Integer array of healpix pixels.
nest (bool, optional) – Are the pixels in nest scheme? Default is True.
valid_mask (bool, optional) – Return mask of True/False instead of values

Returns

values – Array of values/validity from the map.

Return type

np.ndarray

get_values_pos(theta_or_ra, phi_or_dec, lonlat=False, valid_mask=False)[source]¶

Get the map value for the position. Positions may be theta/phi co-latitude and longitude in radians, or longitude and latitude in degrees.

Parameters

theta_or_ra (float, array-like) – Angular coordinates of points on a sphere.
phi_or_dec (float, array-like) – Angular coordinates of points on a sphere.
lonlat (bool, optional) – If True, input angles are longitude and latitude in degrees. Otherwise, they are co-latitude and longitude in radians.
valid_mask (bool, optional) – Return mask of True/False instead of values

Returns

values – Array of values/validity from the map.

Return type

np.ndarray

property is_integer_map¶

Check that the map is an integer map

Returns: is_integer_map
Return type: bool

property is_rec_array¶

Check that the map is a recArray map.

Returns: is_rec_array
Return type: bool

property is_unsigned_map¶

Check that the map is an unsigned integer map

Returns: is_unsigned_map
Return type: bool

property is_wide_mask_map¶

Check that the map is a wide mask

Returns: is_wide_mask_map
Return type: bool

classmethod make_empty(nside_coverage, nside_sparse, dtype, primary=None, sentinel=None, wide_mask_maxbits=None, metadata=None, cov_pixels=None)[source]¶

Make an empty map with nothing in it.

Parameters

nside_coverage (int) – Nside for the coverage map
nside_sparse (int) – Nside for the sparse map
dtype (str or list or np.dtype) – Datatype, any format accepted by numpy.
primary (str, optional) – Primary key for recarray, required if dtype has fields.
sentinel (int or float, optional) – Sentinel value. Default is hp.UNSEEN for floating-point types, and minimum int for int types.
wide_mask_maxbits (int, optional) – Create a “wide bit mask” map, with this many bits.
metadata (dict-like, optional) – Map metadata that can be stored in FITS header format.
cov_pixels (np.ndarray or list) – List of integer coverage pixels to pre-allocate

Returns

healSparseMap – HealSparseMap filled with sentinel values.

Return type

HealSparseMap

classmethod make_empty_like(sparsemap, nside_coverage=None, nside_sparse=None, dtype=None, primary=None, sentinel=None, wide_mask_maxbits=None, metadata=None, cov_pixels=None)[source]¶

Make an empty map with the same parameters as an existing map.

Parameters

sparsemap (HealSparseMap) – Sparse map to use as basis for new empty map.
nside_coverage (int, optional) – Coverage nside, default to sparsemap.nside_coverage
nside_sparse (int, optional) – Sparse map nside, default to sparsemap.nside_sparse
dtype (str or list or np.dtype, optional) – Datatype, any format accepted by numpy. Default is sparsemap.dtype
primary (str, optional) – Primary key for recarray. Default is sparsemap.primary
sentinel (int or float, optional) – Sentinel value. Default is sparsemap._sentinel
wide_mask_maxbits (int, optional) – Create a “wide bit mask” map, with this many bits.
metadata (dict-like, optional) – Map metadata that can be stored in FITS header format.
cov_pixels (np.ndarray or list) – List of integer coverage pixels to pre-allocate

Returns

healSparseMap – HealSparseMap filled with sentinel values.

Return type

HealSparseMap

property metadata¶

Return the metadata dict.

Returns: metadata
Return type: dict

property nside_coverage¶

Get the nside of the coverage map

Returns: nside_coverage
Return type: int

property nside_sparse¶

Get the nside of the sparse map

Returns: nside_sparse
Return type: int

property primary¶

Get the primary field

Returns: primary
Return type: str

classmethod read(filename, nside_coverage=None, pixels=None, header=False)[source]¶

Read in a HealSparseMap.

Parameters

filename (str) – Name of the file to read. May be either a regular HEALPIX map or a HealSparseMap
nside_coverage (int, optional) – Nside of coverage map to generate if input file is healpix map.
pixels (list, optional) – List of coverage map pixels to read. Only used if input file is a HealSparseMap
header (bool, optional) – Return the fits header as well as map? Default is False.

Returns

healSparseMap (HealSparseMap) – HealSparseMap from file, covered by pixels
header (fitsio.FITSHDR or astropy.io.fits (if header=True)) – Fits header for the map file.

set_bits_pix(pixels, bits, nest=True)[source]¶

Set bits of a wide_mask map.

Parameters

pixels (np.ndarray) – Integer array of sparse_map pixel values
bits (list) – List of bits to set

update_values_pix(pixels, values, nest=True, operation='replace')[source]¶

Update the values in the sparsemap for a list of pixels.

Parameters

pixels (np.ndarray) – Integer array of sparse_map pixel values
values (np.ndarray) – Value or Array of values. Must be same type as sparse_map
operation (str, optional) – Operation to use to update values. May be ‘replace’ (default), ‘or’, or ‘and’ (for bit masks)

property valid_pixels¶

Get an array of valid pixels in the sparse map.

Returns: valid_pixels
Return type: np.ndarray

valid_pixels_pos(lonlat=False, return_pixels=False)[source]¶

Get an array with the position of valid pixels in the sparse map.

Parameters

lonlat (bool, optional) – If True, input angles are longitude and latitude in degrees. Otherwise, they are co-latitude and longitude in radians.
return_pixels (bool, optional) – If true, return valid_pixels / co-lat / co-lon or valid_pixels / lat / lon instead of lat / lon

Returns

positions – By default it will return a tuple of the form (theta, phi) in radians unless lonlat = True, for which it will return (ra, dec) in degrees. If return_pixels = True, valid_pixels will be returned as first element in tuple.

Return type

tuple

property wide_mask_maxbits¶

Get the maximum number of bits stored in the wide mask.

Returns: wide_mask_maxbits – Maximum number of bits. 0 if not wide mask.
Return type: int

property wide_mask_width¶

Get the width of the wide mask

Returns: wide_mask_width – Width of wide mask array. 0 if not wide mask.
Return type: int

write(filename, clobber=False)[source]¶

Write heal HealSparseMap to filename. Use the metadata property from the map to persist additional information in the fits header.

Parameters

filename (str) – Name of file to save
clobber (bool, optional) – Clobber existing file? Default is False.

HealSparseRandoms¶

healsparse.healSparseRandoms.make_uniform_randoms(sparse_map, n_random, rng=None)[source]¶

Make an array of uniform randoms.

Parameters

sparse_map (healsparse.HealSparseMap) – Sparse map object
n_random (int) – Number of randoms to generate
rng (np.random.RandomState, optional) – Pre-set Random number generator. Default is None.

Returns

ra_array (np.ndarray) – Float array of RAs (degrees)
dec_array (np.ndarray) – Float array of declinations (degrees)

healsparse.healSparseRandoms.make_uniform_randoms_fast(sparse_map, n_random, nside_randoms=8388608, rng=None)[source]¶

Make an array of uniform randoms.

Parameters

sparse_map (healsparse.HealSparseMap) – Sparse map object
n_random (int) – Number of randoms to generate
nside_randoms (int, optional) – Nside for pixel centers to select random points
rng (np.random.RandomState, optional) – Pre-set Random number generator. Default is None.

Returns

ra_array (np.ndarray) – Float array of RAs (degrees)
dec_array (np.ndarray) – Float array of declinations (degrees)

Operations¶

healsparse.operations.and_intersection(map_list)[source]¶

Bitwise or a list of HealSparseMaps as an intersection. Only pixels that are valid in all the input maps will have valid values in the output. Only works on integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise and
Returns: result – Bitwise and of maps
Return type: HealSparseMap

healsparse.operations.and_union(map_list)[source]¶

Bitwise and a list of HealSparseMaps as a union. Empty values will be treated as 0s in the bitwise and, and the output map will have a union of all the input map pixels. Only works in integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise and
Returns: result – Bitwise and of maps
Return type: HealSparseMap

healsparse.operations.max_intersection(map_list)[source]¶

Element-wise maximum of the intersection of a list of the HealSparseMaps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to compute the maximum of
Returns: result – Element-wise maximum of maps
Return type: HealSparseMap

healsparse.operations.max_union(map_list)[source]¶

Element-wise maximum of the union of a list of HealSparseMaps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to compute the maximum of
Returns: result – Element-wise maximum of maps
Return type: HealSparseMap

healsparse.operations.min_intersection(map_list)[source]¶

Element-wise minimum of the intersection of a list of HealSparseMaps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to compute the minimum of
Returns: result – Element-wise minimum of maps
Return type: HealSparseMap

healsparse.operations.min_union(map_list)[source]¶

Element-wise minimum of the union of a list of HealSparseMaps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to compute the minimum of
Returns: result – Element-wise minimum of maps
Return type: HealSparseMap

healsparse.operations.or_intersection(map_list)[source]¶

Bitwise or a list of HealSparseMaps as an intersection. Only pixels that are valid in all the input maps will have valid values in the output. Only works on integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise or
Returns: result – Bitwise or of maps
Return type: HealSparseMap

healsparse.operations.or_union(map_list)[source]¶

Bitwise or a list of HealSparseMaps as a union. Empty values will be treated as 0s in the bitwise or, and the output map will have a union of all the input map pixels. Only works in integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise or
Returns: result – Bitwise or of maps
Return type: HealSparseMap

healsparse.operations.product_intersection(map_list)[source]¶

Compute the product of a list of HealSparseMaps as an intersection. Only pixels that are valid in all the input maps will have valid values in the output.

Parameters: map_list (list of HealSparseMap) – Input list of maps to take the product
Returns: result – Product of maps
Return type: HealSparseMap

healsparse.operations.product_union(map_list)[source]¶

Compute the product of a list of HealSparseMaps as a union. Empty values will be treated as 1s in the product, and the output map will have a union of all the input map pixels.

Parameters: map_list (list of HealSparseMap) – Input list of maps to take the product
Returns: result – Product of maps
Return type: HealSparseMap

healsparse.operations.sum_intersection(map_list)[source]¶

Sum a list of HealSparseMaps as an intersection. Only pixels that are valid in all the input maps will have valid values in the output.

Parameters: map_list (list of HealSparseMap) – Input list of maps to sum
Returns: result – Summation of maps
Return type: HealSparseMap

healsparse.operations.sum_union(map_list)[source]¶

Sum a list of HealSparseMaps as a union. Empty values will be treated as 0s in the summation, and the output map will have a union of all the input map pixels.

Parameters: map_list (list of HealSparseMap) – Input list of maps to sum
Returns: result – Summation of maps
Return type: HealSparseMap

healsparse.operations.ufunc_intersection(map_list, func, filler_value=0)[source]¶

Apply numpy ufunc to the intersection of a list of HealSparseMaps.

Parameters

map_list (list of HealSparseMap) – Input list of maps where the operation is applied
func (np.ufunc) – Numpy universal function to apply
filler_value (int or float) – Starting value

Returns

result – Resulting map

Return type

HealSparseMap

healsparse.operations.ufunc_union(map_list, func, filler_value=0)[source]¶

Apply numpy ufunc to the union of a list of HealSparseMaps.

Parameters

map_list (list of HealSparseMaps) – Input list of maps where the operation is applied
func (np.ufunc) – Numpy universal function to apply
filler_value (int or float) – Starting value and filler for the union

Returns

result – Resulting map

Return type

HealSparseMap

healsparse.operations.xor_intersection(map_list)[source]¶

Bitwise xor a list of HealSparseMaps as an intersection. Only pixels that are valid in all the input maps will have valid values in the output. Only works on integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise xor
Returns: result – Bitwise xor of maps
Return type: HealSparseMap

healsparse.operations.xor_union(map_list)[source]¶

Bitwise xor a list of HealSparseMaps as a union. Empty values will be treated as 0s in the bitwise or, and the output map will have a union of all the input map pixels. Only works in integer maps.

Parameters: map_list (list of HealSparseMap) – Input list of maps to bitwise xor
Returns: result – Bitwise xor of maps
Return type: HealSparseMap

Geometry Library¶

class healsparse.geom.Circle(*, ra, dec, radius, value)[source]¶

Bases: healsparse.geom.GeomBase

__init__(*, ra, dec, radius, value)[source]¶

Parameters

ra (float) – ra in degrees
dec (float) – dec in degrees
radius (float) – radius in degrees
value (number) – Value for pixels in the map

__repr__()[source]¶: Return repr(self).

property dec¶: get the dec value

get_pixels(*, nside)[source]¶

get the pixels associated with this circle

Parameters: nside (int) – Nside for the pixels

property ra¶: get the ra value

property radius¶: get the radius value

class healsparse.geom.GeomBase[source]¶

Bases: object

base class for goemetric objects that can convert themselves to maps

__weakref__¶: list of weak references to the object (if defined)

get_map(*, nside_coverage, nside_sparse, dtype, wide_mask_maxbits=None)[source]¶

get a healsparse map corresponding to this geometric primitive

Parameters

nside_coverage (int) – nside of coverage map
nside_sparse (int) – nside of sparse map
dtype (np.dtype) – dtype of the output array
wide_mask_maxbits (int, optional) – Create a “wide bit mask” map, with this many bits.

Returns

Return type

HealSparseMap

get_map_like(sparseMap)[source]¶

Get a healsparse map corresponding to this geometric primitive, with the same parameters as an input sparseMap.

Parameters: sparseMap (healsparse.HealSparseMap) – Input map to match parameters
Returns
Return type: HealSparseMap

get_pixels(*, nside)[source]¶

get pixels for this map

Parameters: nside (int) – Nside for the pixels

property is_integer_value¶: Check if the value is an integer type

property value¶: get the value to be used for all pixels in the map

class healsparse.geom.Polygon(*, ra, dec, value)[source]¶

Bases: healsparse.geom.GeomBase

__init__(*, ra, dec, value)[source]¶

represent a polygon

both counter clockwise and clockwise order for polygon vertices works

Parameters

ra (array) – ra of vertices in degrees, size [nvert]
dec (array) – dec of vertices in degrees, size [nvert]
value (number) – Value for pixels in the map

__repr__()[source]¶: Return repr(self).

property dec¶: get the dec value

get_pixels(*, nside)[source]¶

get the pixels associated with this polygon

Parameters: nside (int) – Nside for the pixels

property ra¶: get the ra value

property vertices¶: get the dec value

healsparse.geom.realize_geom(geom, smap, type='or')[source]¶

Realize geometry objects in a map

Parameters

geom (geometric primitive or list thereof) – List of Geom objects, e.g. Circle, Polygon
smap (HealSparseMaps) – The map in which to realize the objects
type (string) – Way to combine the list of geometric objects. Default is to “or” them

HealSparseCoverage¶

class healsparse.healSparseCoverage.HealSparseCoverage(cov_index_map, nside_sparse)[source]¶

Bases: object

Class to define a HealSparseCoverage map

__init__(cov_index_map, nside_sparse)[source]¶

Instantiate a HealSparseCoverage map.

Returns: healSparseCoverage
Return type: HealSparseCoverage

__weakref__¶: list of weak references to the object (if defined)

append_pixels(sparse_map_size, new_cov_pix, check=True, copy=True)[source]¶

Append new pixels to the coverage map

Parameters

sparse_map_size (int) – Size of current sparse map
new_cov_pix (np.ndarray) – Array of new coverage pixels

property bit_shift¶

Get the bit_shift for the coverage map

Returns: bit_shift – Number of bits to shift from coarse to fine maps
Return type: int

cov_pixels(sparse_pixels)[source]¶

Get coverage pixel numbers (nest) from a set of sparse pixels.

Parameters: sparse_pixels (np.ndarray) – Array of sparse pixels
Returns: cov_pixels – Coverage pixel numbers (nest format)
Return type: np.ndarray

cov_pixels_from_index(index)[source]¶

Get the coverage pixels from the sparse map index.

Parameters: index (np.ndarray) – Array of indices in sparse map
Returns: cov_pixels – Coverage pixel numbers (nest format)
Return type: np.ndarray

property coverage_mask¶

Get the boolean mask of the coverage map.

Returns: cov_mask – Boolean array of coverage mask.
Return type: np.ndarray

initialize_pixels(cov_pix)[source]¶

Initialize pixels in the index map

Parameters: cov_pix (np.ndarray) – Array of coverage pixels

classmethod make_empty(nside_coverage, nside_sparse)[source]¶

Make an empty coverage map.

Parameters

nside_coverage (int) – Healpix nside for the coverage map
nside_sparse (int) – Healpix nside for the sparse map

Returns

healSparseCoverage – HealSparseCoverage from file

Return type

HealSparseCoverage

classmethod make_from_pixels(nside_coverage, nside_sparse, cov_pixels)[source]¶

Make an empty coverage map.

Parameters

nside_coverage (int) – Healpix nside for the coverage map
nside_sparse (int) – Healpix nside for the sparse map
cov_pixels (np.ndarray) – Array of coverage pixels

Returns

healSparseCoverage – HealSparseCoverage from file

Return type

HealSparseCoverage

property nfine_per_cov¶

Get the number of fine (sparse) pixels per coarse (coverage) pixel

Returns: nfine_per_cov – Number of fine (sparse) pixels per coverage pixel
Return type: int

property nside_coverage¶

Get the nside of the coverage map

Returns: nside_coverage
Return type: int

property nside_sparse¶

Get the nside of the associated sparse map

Returns: nside_sparse
Return type: int

classmethod read(filename_or_fits)[source]¶

Read in HealSparseCoverage.

Returns: healSparseCoverage – HealSparseCoverage from file
Return type: HealSparseCoverage

Concatenation¶

healsparse.cat_healsparse_files.cat_healsparse_files(file_list, outfile, check_overlap=False, clobber=False, in_memory=False, nside_coverage_out=None)[source]¶

Concatenate healsparse files together in a memory-efficient way.

Parameters

file_list (list of str) – List of filenames to concatenate
outfile (str) – Output filename
check_overlap (bool, optional) – Check that each file has a unique sparse map. This may be slower.
clobber (bool, optional) – Clobber existing outfile
in_memory (bool, optional) – Do operations in-memory (required unless fitsio is available).
nside_coverage_out (int, optional) – Output map with specific nside_coverage. Default is nside_coverage of first map in file_list.