.. _level3-format:

Output Format
=============

Data organization
^^^^^^^^^^^^^^^^^

The data are organized in a gridded data structure, i.e. data cubes.
The tiles manifest as directories in the file system, and the images are stored within.

.. seealso:: 

  Check out this `tutorial <https://davidfrantz.github.io/tutorials/force-datacube/datacube/>`_, which explains what a datacube is, how it is parameterized, how you can find a POI, how to visualize the tiling grid, and how to conveniently display cubed data.


Data Cube definition
^^^^^^^^^^^^^^^^^^^^

The spatial data cube definition is appended to each data cube, i.e. to each directory containing tiled datasets, see :ref:`datacube-def`.


File format
^^^^^^^^^^^

Refer to :ref:`hl-format` for details on the file format and metadata.


Naming convention
^^^^^^^^^^^^^^^^^

Following 29-digit naming convention is applied to all output files:

Example filename: 20160701_LEVEL3_LNDLG_BAP.tif

+--------+-------+-----------------------------------------+
+ Digits + Description                                     +
+========+=======+=========================================+
+ 1–8    + Target date as YYYYMMDD                         +
+--------+-------+-----------------------------------------+
+ 10–15  + Product Level                                   +
+--------+-------+-----------------------------------------+
+ 17–21  + Sensor ID                                       +
+        +-------+-----------------------------------------+
+        + LNDLG + Landsat legacy bands                    +
+        +-------+-----------------------------------------+
+        + SEN2L + Sentinel-2 land bands                   +
+        +-------+-----------------------------------------+
+        + SEN2H + Sentinel-2 high-res bands               +
+        +-------+-----------------------------------------+
+        + R-G-B + Visible bands                           +
+        +-------+-----------------------------------------+
+        + VVVHP + VV/VH Dual Polarized                    +
+--------+-------+-----------------------------------------+
+ 23–25  + Product Type                                    +
+        +-------+-----------------------------------------+
+        + BAP   + Best Available Pixel composite          +
+        +-------+-----------------------------------------+
+        + INF   + Compositing Information                 +
+        +-------+-----------------------------------------+
+        + SCR   + Compositing Score                       +
+--------+-------+-----------------------------------------+
+ 27–29  + File extension                                  +
+        +-------+-----------------------------------------+
+        + tif   + image data in compressed GeoTiff format +
+        +-------+-----------------------------------------+
+        + dat   + image data in flat binary ENVI format   +
+        +-------+-----------------------------------------+
+        + hdr   + metadata for ENVI format                +
+--------+-------+-----------------------------------------+


Product type
^^^^^^^^^^^^

* Best Available Pixel composite

  A Best Available Pixel (BAP) composite is a reflectance product.
  It holds the reflectance of the most suitable observation - for each pixel.
  The scale is 10000, and nodata value is -9999.
  The product contains multiple bands, which represent wavelengths.
  The number of bands is dependent on the ``SENSOR`` used.
  All overlapping bands are used, and the output product is named according to this band set (see table above).

* Compositing Information

  The Compositing Information (INF) product contains information about the selected observation in the BAP product. It is a multi-band image:
  
  +------+----------------------------------------------------------------------------+
  + Band + Description                                                                +
  +======+============================================================================+
  + 1    + Quality Assurance Information of best observation (see :ref:`qai`)         +
  +------+----------------------------------------------------------------------------+
  + 2    + Number of cloud-free observations within compositing period                +
  +------+----------------------------------------------------------------------------+
  + 3    + Acquisition DOY of best observation                                        +
  +------+----------------------------------------------------------------------------+
  + 4    + Acquisition Year of best observation                                       +
  +------+----------------------------------------------------------------------------+
  + 5    + Difference between band 3 and Target DOY                                   +
  +------+----------------------------------------------------------------------------+
  + 6    + Sensor ID  of best observation (in the order given in the :ref:`l3-param`) +
  +------+----------------------------------------------------------------------------+

* Compositing Score

  The Compositing Score (SCR) product contains the scores of the selected observation in the BAP product.
  The score is between 0 and 1, the scaling factor is 10000. 
  It is a multi-band image:
  
  +------+---------------------------------+
  + Band + Description                     +
  +======+=================================+
  + 1    + Total score                     +
  +------+---------------------------------+
  + 2    + DOY score (intra-annual score)  +
  +------+---------------------------------+
  + 3    + Year score (inter-annual score) +
  +------+---------------------------------+
  + 4    + Cloud distance score            +
  +------+---------------------------------+
  + 5    + Haze score                      +
  +------+---------------------------------+
  + 6    + Correlation score               +
  +------+---------------------------------+
  + 7    + View angle score                +
  +------+---------------------------------+


Quicklooks
^^^^^^^^^^

If ``OUTPUT_OVV = TRUE``, small quicklooks images are generated,
The quicklooks are fixed-stretch images.
For optical images, they are RGB quicklooks.
For radar images, RGB refer to VV, VH, and VV/VH ratio.