.. _VMPZIDHEALPixFootprintMask:

.. include:: ../../idsubstitutions.txt

Output Product: HEALPix Footprint Mask
--------------------------------------

Data product name
=================
.. DataProductNameStart

VMPZIDHEALPixFootprintMask

.. DataProductNameEnd

Data product custodian
======================
.. DataProductCustodianStart

VMPZ-ID

.. DataProductCustodianEnd

Data model tag
==============
.. DataModelTagStart

|ML2A2BF|

.. DataModelTagEnd

Name of the Schema file
=======================
.. NameSchemaStart

|ML2A2BF|

.. NameSchemaEnd

Schema documentation tag
========================
.. SchemaDocTagStart

|ML2A2BF|

.. SchemaDocTagEnd

Data product elements
=====================
.. DataProductElementsStart

|ML2A2BF|

.. DataProductElementsEnd

Processing Element(s) creating/using the data product
=====================================================
.. PECreatorStart

VMPZ-ID, (CM-)PK-WL

.. PECreatorEnd

Processing function using the data product
==========================================
.. PFUsingStart

LE3

.. PFUsingEnd

Detailed description of the data product
========================================
.. DetailedDescStart

This output product is essentially the footprint of the survey for a given band/instrument.
The **FootprintMaskHealpix** metadata includes a container with a FITS file (of type le3.id.vmpz.healpixfootprintmask)
describing the footprint for the survey in partial HEALPix format,
for a given observed band/instrument (Euclid/EXT), and a raw description with polygons
of the envelope of the sky covered is added as well to ease future queries on the product
(**SpatialCoverage** metadata, see `spatialFootprint <https://gitlab.euclid-sgs.uk/ST-DM/ST_DataModel/blob/develop/dictionary/bas/cot/euc-test-cot.xsd>`_).
Finally, the mask parameters **FootprintMaskHealpixParams** can optionally be associated to the product.

Keywords (Primary HDU)
++++++++++++++++++++++

The primary HDU is expected to contain the following keywords, characterizing
important parameters of the input product:

#. **DATE-OBS**: start of observation with format 'yyyy-mm-ddThh:mm:ss.sss' [StringKeyword]
#. **DATE-END**: end of observation with format 'yyyy-mm-ddThh:mm:ss.sss' [StringKeyword]
#. **TELESCOP**: name of the telescope [StringKeyword]
#. **INSTRUME**: name of the instrument [StringKeyword]
#. **FILTER**: name of the filter [StringKeyword]
#. **FILTLST**: selection of filter if intersection of multiple footprints [StringKeyword]
#. **TILEID**: identifier of the MER Tile processed (-1 if multiple Tiles) [IntegerKeyword]
#. **LISTID**: identifier of a MER list of tiles product (-1 if single Tile) [StringKeyword]
#. **NSIDE_WK**: Nside parameter used for frame->HEALPix [StringKeyword]

   and basic software parameters:

#. **SOFTNAME**: name of software used [StringKeyword]
#. **SOFTVERS**: version of software used  [StringKeyword]

Partial HEALPix Footprint Table (First Extension, Binary Table)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

The following keywords are used to describe what HEALPix conventions are followed:

#. **TTYPE1**  (= 'PIXEL') [StringKeyword]
#. **TFORM1**  (= 'K') [StringKeyword]
#. **TTYPE2**  (= 'WEIGHT') [StringKeyword]
#. **TFORM2**  (= 'E') [StringKeyword]
#. **PIXTYPE** (= 'HEALPIX') [StringKeyword]
#. **ORDERING** (= 'RING' or 'NESTED') [StringKeyword]
#. **COORDSYS** (= 'C'=celestial, 'E'=ecliptic or 'G'=galactic) [StringKeyword]
#. **EXTNAME** (= 'FOOTPRINT_MASK') [StringKeyword]
#. **NSIDE** [IntegerKeyword]
#. **INDEXSCHM** (= 'EXPLICIT') [StringKeyword]
#. **OBJECT** (= 'PARTIAL') [StringKeyword]

The table is then expected to contain the following columns:

#. **PIXEL**: index of pixel [K, int64]
#. **WEIGHT**: weight associated to pixel in [0,1] indicating the fraction of the pixel
   actually covered by the footprint (1: fully not observed regions) [E, float32]

.. DetailedDescEnd