SourceGroups#

class photutils.psf.SourceGroups(x, y, groups)[source]#

Bases: object

Container for source grouping results with analysis methods.

This class stores the results of grouping sources and provides methods to analyze and query the grouping.

Parameters:

x, y1D float ndarray: The 1D arrays of the x and y coordinates of the sources.
groups1D int ndarray: A 1D array of the group IDs, in the same order as the input x and y coordinates.

Attributes:

xndarray: The x coordinates of the sources.
yndarray: The y coordinates of the sources.
groupsndarray: The group IDs for each source.
n_sourcesint: Total number of sources.
n_groupsint: Total number of groups.

See also

SourceGrouper

Examples

Create a SourceGroups object:

>>> from photutils.psf import SourceGroups
>>> import numpy as np
>>> x = np.array([10, 15, 50, 55, 100])
>>> y = np.array([20, 25, 60, 65, 90])
>>> groups = np.array([1, 1, 2, 2, 3])
>>> source_groups = SourceGroups(x, y, groups)
>>> print(source_groups)
<SourceGroups(n_sources=5, n_groups=3)>

Access properties of the SourceGroups object:

>>> print(f'Number of groups: {source_groups.n_groups}')
Number of groups: 3
>>> source_groups.size_map
{1: 2, 2: 2, 3: 1}
>>> source_groups.sizes
array([2, 2, 2, 2, 1])
>>> source_groups.group_centers
{1: (12.5, 22.5), 2: (52.5, 62.5), 3: (100.0, 90.0)}
>>> x_group1, y_group1 = source_groups.get_group_sources(1)
>>> print(x_group1, y_group1)
[10 15] [20 25]

Attributes Summary

`group_centers`	Centroid coordinates of each group.
`size_map`	Mapping of group ID to group size.
`sizes`	Size of each group for each source.

Methods Summary

`get_group_sources`(group_id)	Get the coordinates of all sources in a specific group.
`plot`(radius, *[, ax, cmap, seed, ...])	Plot circular apertures around sources, color-coded by group.

Attributes Documentation

group_centers#

Centroid coordinates of each group.

Returns:

group_centersdict: A dictionary where keys are group IDs and values are tuples of (x_center, y_center) representing the centroid of each group.

size_map#

Mapping of group ID to group size.

Returns:

size_mapdict: A dictionary where keys are group IDs and values are the corresponding group sizes.

sizes#

Size of each group for each source.

Returns:

group_sizes1D int ndarray: A 1D array of the group sizes, in the same order as the sources. Each element indicates how many sources are in the same group as the corresponding source.

Methods Documentation

get_group_sources(group_id)[source]#

Get the coordinates of all sources in a specific group.

Parameters:

group_idint: The group ID to retrieve sources for.

Returns:

x, yndarray: Arrays of x and y coordinates for all sources in the specified group.

plot(radius, *, ax=None, cmap=None, seed=0, label_groups=False, label_kwargs=None, label_offset=(0, 0), **kwargs)[source]#

Plot circular apertures around sources, color-coded by group.

Parameters:

radiusfloat: The radius of the circles to plot around each source (in pixels).
axAxes, optional: The matplotlib axes on which to plot. If None, uses the current axes.
cmapColormap or str, optional: The colormap to use for group colors. If None, a random colormap is generated.
seedint, optional: Random seed for generating the colormap if cmap is None.
label_groupsbool, optional: Whether to label each group with its group ID at the group center.
label_kwargsdict, optional: Keyword arguments passed to ax.text for plotting group ID labels.
label_offsettuple of float, optional: Offset (dx, dy) in pixels for positioning labels relative to group centers. Positive values move right/up, negative values move left/down. Default is (0, 0).
**kwargs: Additional keyword arguments passed to plot.

Returns:

axAxes: The matplotlib axes object.