.. lsst-task-topic:: lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask

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HealSparsePropertyMapTask
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``HealSparsePropertyMapTask`` generates a set of survey property maps in `healsparse <https://healsparse.readthedocs.io/en/stable>`_ format.
One map is created per map type per tract per band.

The resolution of the maps is set by the resolution configured for :doc:`lsst.pipe.tasks.healSparseMapping.HealSparseInputMapTask` and run during the coadd assembly.

The maps to be run are configured through the "property map registry", and new maps can be defined via the ``lsst.pipe.tasks.healSparseMappingProperties.register_property_map`` decorator.
Maps can do computations with any values that are available via the visit summaries produced by :doc:`lsst.pipe.tasks.postprocess.ConsolidateVisitSummaryTask`.

Each map type can be configured to compute the minimum value at each position (``do_min``, dataset type ``{name}_map_min``); the maximum value (``do_max``, dataset type ``{name}_map_max``); the mean value (``do_mean``, dataset type ``{name}_map_mean``); the weighted mean, using the coadd weights (``do_weighted_mean``, dataset type ``{name}_map_weighted_mean``); and the sum (``do_sum``, dataset type ``{name}_map_sum``).
In each case ``{name}`` refers to the registered name of the map.

Supported Map Types
===================
The following map types are supported, and it is possible to add more by subclassing ``lsst.pipe.tasks.healSparseMappingProperties.BasePropertyMap``.
All values are sampled at the center of each map pixel.
All PSF properties are estimated by realizing the PSF model over a grid of points on each detector and approximating the variation with a second-order Chebyshev polynomial.

- ``exposure_time``: The input visit exposure time, usually with ``do_sum=True``.
- ``psf_size``: The size of the PSF as computed from the determinant radius (pixels).
- ``psf_e1``: The PSF e1 ellipticity.
- ``psf_e2``: The PSF e2 ellipticity.
- ``n_exposure``: The number of exposures, usually with ``do_sum=True``.
- ``psf_maglim``: The magnitude limit for PSF magnitudes.  Can only be used with ``do_weighted_mean=True``.
- ``sky_background`` : The sky background, scaled to nJy.
- ``sky_noise``: The sky noise, scaled to nJy.
- ``dcr_dra``: The shift in the RA position of sources due to differential chromatic refraction (DCR) will be an empirically determined constant multiplied by the object color multiplied by this map.
- ``dcr_ddec``: The shift in the Dec position of the sources due to DCR.
- ``dcr_e1``: The shift in the ellipticity e1 due to DCR will be an empirically determined constant multipled by the object color multiplied by this map.
- ``dcr_e2``: The shift in the ellipticity e2 due to DCR.

.. _lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask-api:

Python API summary
==================

.. lsst-task-api-summary:: lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask

.. _lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask-subtasks:

Retargetable subtasks
=====================

.. lsst-task-config-subtasks:: lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask

.. _lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask-fields:

Configuration fields
====================

.. lsst-task-config-fields:: lsst.pipe.tasks.healSparseMapping.HealSparsePropertyMapTask