FitTanSipWcsTask¶
- class lsst.meas.astrom.FitTanSipWcsTask(config: Config | None = None, *, name: str | None = None, parentTask: Task | None = None, log: logging.Logger | lsst.utils.logging.LsstLogAdapter | None = None)¶
Bases:
Task
Fit a TAN-SIP WCS given a list of reference object/source matches.
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
fitWcs
(matches, initWcs[, bbox, refCat, ...])Fit a TAN-SIP WCS from a list of reference object/source matches
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.
initialWcs
(matches, wcs)Generate a guess Wcs from the astrometric matches
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.plotFit
(matches, wcs, rejected)Plot the fit
rejectMatches
(matches, wcs, rejected)Flag deviant matches
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Methods Documentation
- fitWcs(matches, initWcs, bbox=None, refCat=None, sourceCat=None, exposure=None)¶
Fit a TAN-SIP WCS from a list of reference object/source matches
- Parameters:
- matches
list
oflsst.afw.table.ReferenceMatch
The following fields are read:
match.first (reference object) coord
match.second (source) centroid
The following fields are written:
match.first (reference object) centroid,
match.second (source) centroid
match.distance (on sky separation, in radians)
- initWcs
lsst.afw.geom.SkyWcs
initial WCS
- bbox
lsst.geom.Box2I
the region over which the WCS will be valid (an lsst:afw::geom::Box2I); if None or an empty box then computed from matches
- refCat
lsst.afw.table.SimpleCatalog
reference object catalog, or None. If provided then all centroids are updated with the new WCS, otherwise only the centroids for ref objects in matches are updated. Required fields are “centroid_x”, “centroid_y”, “coord_ra”, and “coord_dec”.
- sourceCat
lsst.afw.table.SourceCatalog
source catalog, or None. If provided then coords are updated with the new WCS; otherwise only the coords for sources in matches are updated. Required fields are “slot_Centroid_x”, “slot_Centroid_y”, and “coord_ra”, and “coord_dec”.
- exposure
lsst.afw.image.Exposure
Ignored; present for consistency with FitSipDistortionTask.
- matches
- Returns:
- result
lsst.pipe.base.Struct
with the following fields:
wcs
: the fit WCS (lsst.afw.geom.SkyWcs
)scatterOnSky
: median on-sky separation between reference objects and sources in “matches” (lsst.afw.geom.Angle
)
- result
- 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
- initialWcs(matches, wcs)¶
Generate a guess Wcs from the astrometric matches
We create a Wcs anchored at the center of the matches, with the scale of the input Wcs. This is necessary because matching returns only matches with no estimated Wcs, and the input Wcs is a wild guess. We’re using the best of each: positions from the matches, and scale from the input Wcs.
- Parameters:
- matches
list
oflsst.afw.table.ReferenceMatch
List of sources matched to references.
- wcs
lsst.afw.geom.SkyWcs
Current WCS.
- matches
- Returns:
- newWcs
lsst.afw.geom.SkyWcs
Initial WCS guess from estimated crpix and crval.
- newWcs
- 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
.
- plotFit(matches, wcs, rejected)¶
Plot the fit
We create four plots, for all combinations of (dx, dy) against (x, y). Good points are black, while rejected points are red.
- Parameters:
- matches
list
oflsst.afw.table.ReferenceMatch
List of sources matched to references.
- wcs
lsst.afw.geom.SkyWcs
Fitted WCS.
- rejectedarray-like of
bool
Array of matches rejected from the fit.
- matches
- rejectMatches(matches, wcs, rejected)¶
Flag deviant matches
We return a boolean numpy array indicating whether the corresponding match should be rejected. The previous list of rejections is used so we can calculate uncontaminated statistics.
- Parameters:
- matches
list
oflsst.afw.table.ReferenceMatch
List of sources matched to references.
- wcs
lsst.afw.geom.SkyWcs
Fitted WCS.
- rejectedarray-like of
bool
Array of matches rejected from the fit. Unused.
- matches
- Returns:
- rejectedMatches
ndarray
of typebool
Matched objects found to be outside of tolerance.
- rejectedMatches