Level-2 Product Formatting - Sentinel-1 SAR Technical Guide - Sentinel Online
Level 2 Product Formatting
The top-level Sentinel-1 product folder name is composed of upper-case alphanumeric characters separated by an underscore (_).
Product Folder Naming Convention
The Mission Identifier (MMM) denotes the satellite and will be either S1A for the Sentinel-1A instrument or S1B for the Sentinel-1B instrument.
The Mode/Beam (BB) identifies the S1-S6 beams for SM products and IW, EW and WV for products from the respective modes.
The Processing Level (L) can be 0, 1 or 2.
The Product Class can be Standard (S) or Annotation (A). Annotation products are only used internally by the PDGS and are not distributed.
Polarisation (PP) can be:
- SH (single HH polarisation)
- SV (single VV polarisation)
- DH (dual HH+HV polarisation)
- DV (dual VV+VH polarisation).
The product start and stop date and times are shown as fourteen digits representing the date and time, separated by the character 'T'.
The absolute orbit number at product start time (OOOOOO) will be in the range 000001-999999.
The mission data-take identifier (DDDDDD) will be in the range 000001-FFFFFF. The product unique identifier (CCCC) is a hexadecimal string generated by computing CRC-16 on the manifest file using CRC-CCITT.
The folder extension is always "SAFE".
Within a product folder, measurement data sets and annotation data sets follow a similar naming convention with alphanumeric characters separated by a dash (-). All characters are lower case, but the datatake ID that can be annotated either in lower or upper case.
Dataset Naming Convention
The Mission Identifier (mmm) denotes the satellite and will be either s1a for the Sentinel-1A instrument or s1b for the Sentinel-1B instrument.
The Swath Identifier (sss) identifies the s1-s6 beams for SM mode, iw1-iw3 or iw for IW mode, ew1-ew5 or ew for EW more and wv1-wv2 for WV mode.
Product Type (ttt) can be slc, grd or ocn.
Polarisation (pp) can be:
- hh (single HH polarisation)
- vv (single VV polarisation)
- hv (single HV polarisation)
- vh (single VH polarisation).
The product start and stop date and times are shown by fourteen digits representing the date and time separated by the character 't'.
The absolute orbit number at product start time (oooooo) will be in the range 000001-999999.
The mission data-take identifier (dddddd) will be in the range 000001-FFFFFF.
The image number (nnn) identifies each individual image. WV vignettes each have their own image number as do each swath and polarisation image for SM, IW and EW.
The file extension denotes the data format of the file and could be nc, xml, html, kml, xsd or png.
Sentinel-SAFE File Format
Sentinel data products are distributed using a Sentinel-specific variation of the Standard Archive Format for Europe (SAFE) specification with measurement data sets in NetCDF files. The SAFE format has been designed to act as a common format for archiving and conveying data within ESA Earth Observation archiving facilities. SAFE was recommended for the harmonization of the Copernicus missions by the GMES Product Harmonisation Study.
The Sentinel-SAFE format wraps a folder containing image data in a binary data format and product metadata in XML. This flexibility allows the format to be scalable enough to represent all levels of Sentinel products.
A Sentinel product refers to a directory folder that contains a collection of information. It includes:
- a manifest.safe file which holds the general product information in XML
- subfolders for measurement data sets containing Level-2 data and metadata in NetCDF format
- a preview folder containing footprints in Google Earth overlays in KML format and HTML preview files
- a support folder containing the XML schemes describing the product XML.
The data delivered is packaged as a file structure containing a manifest file in XML format listing general product metadata and subfolders for measurement data, previews and support files.
Product Folder File Structure
The manifest file is an XML file containing the mandatory product metadata common to all Sentinel-1 products.
The preview folder contains Google Earth KML files and an HTML preview summary.
Representation data sets found in the support folder contain information about the format or syntax of the measurement and annotated data sets and can be used to validate and exploit these data. Representation data sets are provided as XML schemas.
Measurement data sets contain the binary information of the actual acquired or processed data. The Level-2 OCN products include both the metadata and measurement data sets described as NetCDF attributes, dimensions and variables in self-describing, self-contained NetCDF files.
For further details on the Sentinel-1 Level-2 product formatting, please refer to the Sentinel-1 Level-1 and Level-2 Product Specification document.