CatalogCalculationClassificationPlugin

class lsst.meas.base.CatalogCalculationClassificationPlugin(config, name, schema, metadata)

Bases: lsst.meas.base.CatalogCalculationPlugin

Plugin which calculates a binary measure of source extendedness.

Extendedness is based on a simple cut of the ratio of the PSF flux to the model flux.

Notes

Because the fluxes on which this algorithm is based on are slot measurements, they can be provided by different algorithms, and the fluxRatio threshold used by this algorithm should generally be set differently for different algorithms. To do this, plot the difference between the PSF magnitude and the model magnitude vs. the PSF magnitude, and look for where the cloud of galaxies begins.

Attributes Summary

APCORR_ORDER
CENTROID_ORDER
DEFAULT_CATALOGCALCULATION
FLUX_ORDER
SHAPE_ORDER
plugType
registry

Methods Summary

calculate(measRecord)	Perform the calculation specified by this plugin.
fail(measRecord[, error])	Record a failure of the measure or measureN method.
getExecutionOrder()	Used to set the relative order of plugin execution.
getLogName()
getTransformClass()	Get the measurement transformation appropriate to this plugin.

Attributes Documentation

APCORR_ORDER = 3.0

CENTROID_ORDER = 0.0

DEFAULT_CATALOGCALCULATION = 4.0

FLUX_ORDER = 2.0

SHAPE_ORDER = 1.0

plugType = 'single'

registry = <lsst.meas.base.pluginRegistry.PluginRegistry object>

Methods Documentation

calculate(measRecord)

Perform the calculation specified by this plugin.

This method can either be used to operate on a single catalog record or a whole catalog, populating it with the output defined by this plugin.

Note that results may be added to catalog records as new columns, or may result in changes to existing values.

Parameters:

cat : lsst.afw.table.SourceCatalog or lsst.afw.table.SourceRecord

May either be a SourceCatalog or a single SourceRecord, depending on the plugin type. Will be updated in place to contain the results of plugin execution.

**kwargs

Any additional keyword arguments that may be passed to the plugin.

fail(measRecord, error=None)

Record a failure of the measure or measureN method.

Parameters:

measRecord : lsst.afw.table.SourceRecord

Table record describing the source being measured.

error : MeasurementError, optional

Only provided if the measurement failed due to a MeasurementError being raised; otherwise, will be None.

Notes

When the plugin raises an exception, framework will call BasePlugin.fail to allow the plugin to set its failure flag field(s). When BasePlugin.measureN raises an exception, BasePlugin.fail will be called repeatedly with all the records that were being measured.

If the exception is an MeasurementError, it will be passed as the error argument; in all other cases the error argument will be None, and the failure will be logged by the measurement framework as a warning.

classmethod getExecutionOrder()

Used to set the relative order of plugin execution.

The values returned by getExecutionOrder are compared across all plugins, and smaller numbers run first.

Notes

CatalogCalculationPlugins must run with BasePlugin.DEFAULT_CATALOGCALCULATION or higher.

All plugins must implement this method with an appropriate run level

getLogName()

static getTransformClass()

Get the measurement transformation appropriate to this plugin.

This returns a subclass of transforms.MeasurementTransform, which may be instantiated with details of the algorithm configuration and then called with information about calibration and WCS to convert from raw measurement quantities to calibrated units. Calibrated data is then provided in a separate output table.

Notes

By default, we copy everything from the input to the output without transformation.