TransformSourceTableTask¶

TransformSourceTableTask transforms the full-width source table (a source dataset) to a narrower Source Table (a sourceTable dataset) as specified by the Data Products Definition Document (DPDD). It extracts, transforms, and renames columns per a yaml specification, by default the schemas/Source.yaml in this package. Inputs and outpus are both per-detector. The input is typically a wide table and output a narrow table appropriate for concatenating into a per-visit table by ConsolidateSourceTableTask.

It is the second of three postprocessing tasks to convert a src table to a per-visit Source Table that conforms to the standard data model. The first is WriteSourceTableTask, and the third is ConsolidateSourceTableTask.

Processing summary¶

TransformSourceTableTask

Read in source.

#. Generate functors (by instantiating a lsst.pipe.tasks.functors.CompositeFunctor) from the yaml specification. Apply functors to the columns.

Store output DataFrame in parquet-formatted sourceTable

Python API summary¶

from lsst.pipe.tasks.postprocess import TransformSourceTableTask

classTransformSourceTableTask(*args, **kwargs): Transform/standardize a source catalog...

attributeconfig: Access configuration fields and retargetable subtasks.

methodrun(handle, funcs=None, dataId=None, band=None): Do postprocessing calculations...

Butler datasets¶

When run through the runQuantum method, TransformSourceTableTask obtains datasets from the input Butler data repository and persists outputs to the output Butler data repository. Note that configurations for TransformSourceTableTask, and its subtasks, affect what datasets are persisted and what their content is.

Input datasets¶

source: Full-width parquet version of the src catalog. It is generated by WriteSourceTableTask

Output datasets¶

sourceTable: Source Table in parquet format (per-detector)

Retargetable subtasks¶

No subtasks.

Configuration fields¶

columnsFromDataId¶

Default: None
Field type: str ListField (optional)

Columns to extract from the dataId

connections¶

Data type: lsst.pipe.base.config.TransformSourceTableConfigConnections
Field type: ConfigField

Configurations describing the connections of the PipelineTask to datatypes

functorFile¶

Default: None
Field type: str Field (optional)

Path to YAML file specifying Science Data Model functors to use when copying columns and computing calibrated values.

primaryKey¶

Default: None
Field type: str Field (optional)

Name of column to be set as the DataFrame index. If None, the indexwill be named id

saveLogOutput¶

Default: True
Field type: bool Field

Flag to enable/disable saving of log output for a task, enabled by default.

Examples¶

The following command shows an example of how to run the task on an example HSC repository using the python API

import os
from lsst.utils import getPackageDir
from lsst.daf.butler import Butler
from lsst.pipe.tasks.postprocess import TransformSourceTableTask

# get input catalogs
butler = Butler('/path/to/repo')
dataId = {'visit': 30504, 'ccd': 51}
source = butler.get('source', dataId=dataId)

# setup task using the obs_subaru Source.yaml specification
config =  TransformSourceTableTask.ConfigClass()
config.functorFile = os.path.join(getPackageDir("obs_subaru"), 'policy', 'Source.yaml')
task = TransformSourceTableTask(config=config)
defaultFunctors = task.getFunctors()

# run the task to get a DataFrame
df = task.run(source, funcs=defaultFunctors, dataId=dataId)

You may also specify your own functors to apply:

import yaml
from  lsst.pipe.tasks.functors import CompositeFunctor

str = """
funcs:
    ApFlux:
        functor: LocalNanojansky
        args:
            - slot_CalibFlux_instFlux
            - slot_CalibFlux_instFluxErr
            - base_LocalPhotoCalib
            - base_LocalPhotoCalibErr
    ApFluxErr:
        functor: LocalNanojanskyErr
        args:
            - slot_CalibFlux_instFlux
            - slot_CalibFlux_instFluxErr
            - base_LocalPhotoCalib
            - base_LocalPhotoCalibErr
"""
exampleFunctors = CompositeFunctor.from_yaml(yaml.load(str))
df = task.run(source, funcs=exampleFunctors, dataId=dataId)

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