AstrometryTask¶
- class lsst.meas.astrom.AstrometryTask(refObjLoader=None, schema=None, **kwargs)¶
Bases:
RefMatchTask
Match an input source catalog with objects from a reference catalog and solve for the WCS.
This task is broken into two main subasks: matching and WCS fitting which are very interactive. The matching here can be considered in part a first pass WCS fitter due to the fitter’s sensitivity to outliers.
- Parameters:
- refObjLoader
lsst.meas.algorithms.ReferenceLoader
A reference object loader object; gen3 pipeline tasks will pass
None
and callsetRefObjLoader
inrunQuantum
.- schema
lsst.afw.table.Schema
Used to set “calib_astrometry_used” flag in output source catalog.
- **kwargs
Additional keyword arguments for pipe_base
lsst.pipe.base.Task.__init__
.
- refObjLoader
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
Get a dictionary of all tasks as a shallow copy.
loadAndMatch
(exposure, sourceCat)Load reference objects overlapping an exposure and match to sources detected on that exposure.
makeField
(doc)Make a
lsst.pex.config.ConfigurableField
for this task.makeSubtask
(name, **keyArgs)Create a subtask as a new instance as the
name
attribute of this task.run
(sourceCat, exposure)Load reference objects, match sources and optionally fit a WCS.
setRefObjLoader
(refObjLoader)Sets the reference object loader for the task.
solve
(exposure, sourceCat)Load reference objects overlapping an exposure, match to sources and fit a WCS
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Methods Documentation
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
Notes
The returned metadata includes timing information (if
@timer.timeMethod
is used) and any metadata set by the task. The name of each item consists of the full task name with.
replaced by:
, followed by.
and the name of the item, e.g.:topLevelTaskName:subtaskName:subsubtaskName.itemName
using
:
in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.
- getFullName() str ¶
Get the task name as a hierarchical name including parent task names.
- Returns:
- fullName
str
The full name consists of the name of the parent task and each subtask separated by periods. For example:
The full name of top-level task “top” is simply “top”.
The full name of subtask “sub” of top-level task “top” is “top.sub”.
The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
See also
getFullName
Get the full name of the task.
- getTaskDict() dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]] ¶
Get a dictionary of all tasks as a shallow copy.
- Returns:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- loadAndMatch(exposure, sourceCat)¶
Load reference objects overlapping an exposure and match to sources detected on that exposure.
- Parameters:
- exposure
lsst.afw.image.Exposure
exposure that the sources overlap
- sourceCat
lsst.afw.table.SourceCatalog.
catalog of sources detected on the exposure
- exposure
- Returns:
- result
lsst.pipe.base.Struct
Result struct with Components:
refCat
: reference object catalog of objects that overlap the exposure (lsst.afw.table.SimpleCatalog
)matches
: Matched sources and references (list
oflsst.afw.table.ReferenceMatch
)matchMeta
: metadata needed to unpersist matches (lsst.daf.base.PropertyList
)
- result
Notes
ignores config.matchDistanceSigma
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
Examples
Provides a convenient way to specify this task is a subtask of another task.
Here is an example of use:
class OtherTaskConfig(lsst.pex.config.Config): aSubtask = ATaskClass.makeField("brief description of task")
- makeSubtask(name: str, **keyArgs: Any) None ¶
Create a subtask as a new instance as the
name
attribute of this task.- Parameters:
- name
str
Brief name of the subtask.
- **keyArgs
Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:
config
.parentTask
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.
- run(sourceCat, exposure)¶
Load reference objects, match sources and optionally fit a WCS.
This is a thin layer around solve or loadAndMatch, depending on config.forceKnownWcs.
- Parameters:
- exposure
lsst.afw.image.Exposure
exposure whose WCS is to be fit The following are read only:
bbox
filter (may be unset)
detector (if wcs is pure tangent; may be absent)
The following are updated:
wcs (the initial value is used as an initial guess, and is required)
- sourceCat
lsst.afw.table.SourceCatalog
catalog of sources detected on the exposure
- exposure
- Returns:
- result
lsst.pipe.base.Struct
with these fields:
refCat
: reference object catalog of objects that overlap the exposure (with some margin) (lsst.afw.table.SimpleCatalog
).matches
: astrometric matches (list
oflsst.afw.table.ReferenceMatch
).scatterOnSky
: median on-sky separation between reference objects and sources in “matches” (lsst.afw.geom.Angle
) orNone
if config.forceKnownWcs TruematchMeta
: metadata needed to unpersist matches (lsst.daf.base.PropertyList
)
- result
- setRefObjLoader(refObjLoader)¶
Sets the reference object loader for the task.
- Parameters:
- refObjLoader
An instance of a reference object loader task or class.
- solve(exposure, sourceCat)¶
Load reference objects overlapping an exposure, match to sources and fit a WCS
- Returns:
- result
lsst.pipe.base.Struct
Result struct with components:
refCat
: reference object catalog of objects that overlap the exposure (with some margin) (lsst::afw::table::SimpleCatalog
).matches
: astrometric matches (list
oflsst.afw.table.ReferenceMatch
).scatterOnSky
: median on-sky separation between reference objects and sources in “matches” (lsst.geom.Angle
)matchMeta
: metadata needed to unpersist matches (lsst.daf.base.PropertyList
)
- result
- Raises:
- TaskError
If the measured mean on-sky distance between the matched source and reference objects is greater than
self.config.maxMeanDistanceArcsec
.
Notes
ignores config.forceKnownWcs