Coverage for python / lsst / cell_coadds / _common_components.py: 90%

1# This file is part of cell_coadds. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (https://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <https://www.gnu.org/licenses/>. 

21 

22from __future__ import annotations 

23 

24__all__ = ("CoaddUnits", "CommonComponents", "CommonComponentsProperties") 

25 

26import enum 

27from abc import ABC, abstractmethod 

28from collections.abc import Mapping 

29from dataclasses import dataclass, field 

30from typing import TYPE_CHECKING 

31 

32if TYPE_CHECKING: 

33 from lsst.afw.geom import Polygon2D, SkyWcs # pragma: no cover 

34 

35 from ._identifiers import ObservationIdentifiers, PatchIdentifiers # pragma: no cover 

36 

37 

38class CoaddUnits(enum.Enum): 

39 """Enumeration of units a coadd's pixels may have. 

40 

41 Notes 

42 ----- 

43 This list is intentionally limited to the units we know we need rather than 

44 units we think somewhat might want (which is also why we do not support any 

45 flux unit other than nJy). 

46 """ 

47 

48 legacy = "legacy" 

49 """Pixels in semi-arbitrary unit obtained by scaling the warps to a common 

50 zeropoint (typically 27). 

51 """ 

52 

53 nJy = "nJy" 

54 """Pixels represent flux in nanojanskies. 

55 """ 

56 

57 chi = "chi" 

58 """Pixels represent a signal-to-noise ratio. 

59 """ 

60 

61 

62@dataclass(frozen=True, eq=False, repr=False) 

63class CommonComponents: 

64 """Struct containing image attributes that are common to all cells in a 

65 patch. 

66 """ 

67 

68 units: CoaddUnits 

69 """Units of the coadd's data pixels. 

70 """ 

71 

72 wcs: SkyWcs 

73 """World Coordinate System object that maps the pixel grid to sky 

74 coordinates. 

75 """ 

76 

77 band: str | None 

78 """String label for the filter bandpass. 

79 

80 May be `None` only for coadds that represent a combination of multiple 

81 passbands (e.g. chi^2 detection coadds), not just to indicate absence of 

82 knowledge. 

83 """ 

84 

85 identifiers: PatchIdentifiers 

86 """Struct of unique identifiers for this coadd's patch.""" 

87 

88 visit_polygons: Mapping[ObservationIdentifiers, Polygon2D] = field(default_factory=dict) 

89 """Mapping each (visit, detector) observation to a polygon within the 

90 patch bounding box.""" 

91 

92 

93class CommonComponentsProperties(ABC): 

94 """A mix-in class that provides properties for all common components to 

95 any derived class that provides a property for the common components struct 

96 itself. 

97 """ 

98 

99 @property 

100 def units(self) -> CoaddUnits: 

101 """Units of the coadd's data pixels.""" 

102 return self.common.units 

103 

104 @property 

105 def wcs(self) -> SkyWcs: 

106 """World Coordinate System object that maps the pixel grid to sky 

107 coordinates. 

108 """ 

109 return self.common.wcs 

110 

111 @property 

112 def band(self) -> str | None: 

113 """String label for the filter bandpass. 

114 

115 May be `None` only for coadds that represent a combination of multiple 

116 passbands (e.g. chi^2 detection coadds), not just to indicate absence 

117 of knowledge. 

118 """ 

119 return self.common.band 

120 

121 @property 

122 def identifiers(self) -> PatchIdentifiers: 

123 """Struct of unique identifiers for this coadd's patch.""" 

124 return self.common.identifiers 

125 

126 @property 

127 @abstractmethod 

128 def common(self) -> CommonComponents: 

129 """Struct of image components common to all cells in a patch.""" 

130 raise NotImplementedError()