LSSTApplications  19.0.0-14-gb0260a2+72efe9b372,20.0.0+7927753e06,20.0.0+8829bf0056,20.0.0+995114c5d2,20.0.0+b6f4b2abd1,20.0.0+bddc4f4cbe,20.0.0-1-g253301a+8829bf0056,20.0.0-1-g2b7511a+0d71a2d77f,20.0.0-1-g5b95a8c+7461dd0434,20.0.0-12-g321c96ea+23efe4bbff,20.0.0-16-gfab17e72e+fdf35455f6,20.0.0-2-g0070d88+ba3ffc8f0b,20.0.0-2-g4dae9ad+ee58a624b3,20.0.0-2-g61b8584+5d3db074ba,20.0.0-2-gb780d76+d529cf1a41,20.0.0-2-ged6426c+226a441f5f,20.0.0-2-gf072044+8829bf0056,20.0.0-2-gf1f7952+ee58a624b3,20.0.0-20-geae50cf+e37fec0aee,20.0.0-25-g3dcad98+544a109665,20.0.0-25-g5eafb0f+ee58a624b3,20.0.0-27-g64178ef+f1f297b00a,20.0.0-3-g4cc78c6+e0676b0dc8,20.0.0-3-g8f21e14+4fd2c12c9a,20.0.0-3-gbd60e8c+187b78b4b8,20.0.0-3-gbecbe05+48431fa087,20.0.0-38-ge4adf513+a12e1f8e37,20.0.0-4-g97dc21a+544a109665,20.0.0-4-gb4befbc+087873070b,20.0.0-4-gf910f65+5d3db074ba,20.0.0-5-gdfe0fee+199202a608,20.0.0-5-gfbfe500+d529cf1a41,20.0.0-6-g64f541c+d529cf1a41,20.0.0-6-g9a5b7a1+a1cd37312e,20.0.0-68-ga3f3dda+5fca18c6a4,20.0.0-9-g4aef684+e18322736b,w.2020.45
LSSTDataManagementBasePackage
transforms.py
Go to the documentation of this file.
1 # This file is part of meas_base.
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 
22 """Measurement transformations.
23 
24 When a measurement plugin is run, it provides raw, uncalibrated outputs such
25 as pixel positions. A transformation may be run as a post-processing step to
26 convert those outputs to calibrated quantities, such as celestial coordinates.
27 
28 At construction, the transformation is passed the configuration and name of
29 the plugin whose outputs it will be transformaing (all fields in the input
30 table produced by that plugin will have their field names prefixed by the
31 plugin name) and a `~lsst.afw.table.SchemaMapper` which holds the schemata for
32 the input and output catalogs and which may be used to directly map fields
33 between the catalogs.
34 
35 When a transformer is called, it is handed a `~lsst.afw.table.SourceCatalog`
36 containing the measurements to be transformed, a `~lsst.afw.table.BaseCatalog`
37 in which to store results, and information about the WCS and calibration of
38 the data. It may be safely assumed that both are contiguous in memory, thus a
39 ``ColumnView`` may be used for efficient processing. If the transformation is
40 not possible, it should be aborted by throwing an exception; if this happens,
41 the caller should assume that the contents of the output catalog are
42 inconsistent.
43 
44 Transformations can be defined in Python or in C++. Python code should inherit
45 from `MeasurementTransform`, following its interface.
46 """
47 
48 from lsst.afw.table import CoordKey
49 from lsst.pex.exceptions import LengthError
50 from . import CentroidResultKey
51 
52 __all__ = ("MeasurementTransform", "NullTransform", "PassThroughTransform", "SimpleCentroidTransform")
53 
54 
56  """Base class for measurement transformations.
57 
58  Parameters
59  ----------
60  config : subclass of `BasePluginConfig`
61  The configuration of the measurement plugin whose outputs are being
62  transformed.
63  name : `str`
64  The name of the measurement plugin whose outputs are being
65  transformed.
66  mapper : `lsst.afw.table.SchemaMapper`
67  Mapping between the input (pre-transformation) and output
68  (transformed) catalogs.
69 
70  Notes
71  -----
72  Create transformations by deriving from this class, implementing
73  `__call__()` and (optionally) augmenting `__init__()`.
74  """
75 
76  def __init__(self, config, name, mapper):
77  self.name = name
78  self.config = config
79 
80  def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib):
81  raise NotImplementedError()
82 
83  @staticmethod
84  def _checkCatalogSize(cat1, cat2):
85  if len(cat1) != len(cat2):
86  raise LengthError("Catalog size mismatch")
87 
88 
90  """Null transform which transfers no data from input to output.
91 
92  This is intended as the default for measurements for which no other
93  transformation is specified.
94 
95  Parameters
96  ----------
97  config : subclass of `BasePluginConfig`
98  The configuration of the measurement plugin whose outputs are being
99  transformed.
100  name : `str`
101  The name of the measurement plugin whose outputs are being
102  transformed.
103  mapper : `lsst.afw.table.SchemaMapper`
104  Mapping between the input (pre-transformation) and output
105  (transformed) catalogs.
106  """
107 
108  def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib):
109  self._checkCatalogSize(inputCatalog, outputCatalog)
110 
111 
113  """Copy fields from input to output without transformation.
114 
115  Parameters
116  ----------
117  config : subclass of `BasePluginConfig`
118  The configuration of the measurement plugin whose outputs are being
119  transformed.
120  name : `str`
121  The name of the measurement plugin whose outputs are being
122  transformed.
123  mapper : `lsst.afw.table.SchemaMapper`
124  Mapping between the input (pre-transformation) and output
125  (transformed) catalogs.
126  """
127 
128  def __init__(self, config, name, mapper):
129  MeasurementTransform.__init__(self, config, name, mapper)
130  for key, field in mapper.getInputSchema().extract(name + "*").values():
131  mapper.addMapping(key)
132 
133  def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib):
134  self._checkCatalogSize(inputCatalog, outputCatalog)
135 
136 
138  """Transform pixel centroid, without uncertainty, to celestial coordinates.
139 
140  Parameters
141  ----------
142  config : subclass of `BasePluginConfig`
143  The configuration of the measurement plugin whose outputs are being
144  transformed.
145  name : `str`
146  The name of the measurement plugin whose outputs are being
147  transformed.
148  mapper : `lsst.afw.table.SchemaMapper`
149  Mapping between the input (pre-transformation) and output
150  (transformed) catalogs.
151  """
152 
153  def __init__(self, config, name, mapper):
154  MeasurementTransform.__init__(self, config, name, mapper)
155  self.coordKey = CoordKey.addFields(mapper.editOutputSchema(), name, "Position from " + name)
156 
157  def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib):
158  self._checkCatalogSize(inputCatalog, outputCatalog)
159  centroidResultKey = CentroidResultKey(inputCatalog.schema[self.name])
160  for inSrc, outSrc in zip(inputCatalog, outputCatalog):
161  self.coordKey.set(outSrc, wcs.pixelToSky(centroidResultKey.get(inSrc).getCentroid()))
lsst::meas::base.transforms.SimpleCentroidTransform.__call__
def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib)
Definition: transforms.py:157
lsst::meas::base.transforms.SimpleCentroidTransform.__init__
def __init__(self, config, name, mapper)
Definition: transforms.py:153
lsst::meas::base.transforms.PassThroughTransform.__call__
def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib)
Definition: transforms.py:133
lsst::meas::base.transforms.SimpleCentroidTransform
Definition: transforms.py:137
lsst::meas::base.transforms.MeasurementTransform.config
config
Definition: transforms.py:78
lsst::meas::base.transforms.MeasurementTransform.__call__
def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib)
Definition: transforms.py:80
lsst::meas::base.transforms.MeasurementTransform.__init__
def __init__(self, config, name, mapper)
Definition: transforms.py:76
lsst::meas::base.transforms.MeasurementTransform._checkCatalogSize
def _checkCatalogSize(cat1, cat2)
Definition: transforms.py:84
lsst::meas::base.transforms.MeasurementTransform
Definition: transforms.py:55
lsst.pex::exceptions::LengthError
Reports attempts to exceed implementation-defined length limits for some classes.
Definition: Runtime.h:76
lsst::afw::table
Definition: table.dox:3
lsst::meas::base.transforms.PassThroughTransform
Definition: transforms.py:112
lsst::meas::base.transforms.NullTransform
Definition: transforms.py:89
lsst::meas::base.transforms.SimpleCentroidTransform.coordKey
coordKey
Definition: transforms.py:155
lsst::meas::base.transforms.MeasurementTransform.name
name
Definition: transforms.py:77
lsst::meas::base.transforms.PassThroughTransform.__init__
def __init__(self, config, name, mapper)
Definition: transforms.py:128
lsst.pex::exceptions
Definition: Exception.h:37
set
daf::base::PropertySet * set
Definition: fits.cc:912
lsst::meas::base.transforms.NullTransform.__call__
def __call__(self, inputCatalog, outputCatalog, wcs, photoCalib)
Definition: transforms.py:108