DRB Extractor

Extractor

An extractor as its name suggests allowing to extract information/data from a node. An extractor is defined by a YAML content. Three extractor types exists currently:

Constant

This extractor nothing from the node but give always the same value.

constant: 42

Some string values are automatically converted to a specific Python type:

XQuery

This extractor allowing to extract data from the node via an XQuery script. See more details about XQuery.

xquery: |
  data(./manifest.safe/XFDU/metadataSection/
  metadataObject[@ID="generalProductInformation"]/metadataWrap/xmlData/
    *[matches(name(),"standAloneProductInformation|generalProductInformation")]/
    noiseCompressionType)

Python

The Python extractor allowing to extract data from a node via a Python script. Where the node variable represents the current node.

python: |
  return node['DATASTRIP'][0]['MTD_DS.xml']['Level-1C_DataStrip_ID']
      ['General_Info']['Datatake_Info'].get_attribute('datatakeIdentifier')

Script

The Script extractor allowing to extract data from a node via a Python method. A DrbNode given in argument of the extract method will be put in argument.

script: package.module:function1 # execute complex python script to generate the preview

example:

drbItemClass: aff2191f-5b06-4121-a9fa-f3d93f6c6331
variables:
  - name: node_platform
    xquery: |
      ./manifest.safe/XFDU/metadataSection/metadataObject[@ID="platform"]/
        metadataWrap/xmlData/platform
metadata:
  - name: 'platformName'
    constant: 'Sentinel-1'
  - name: 'SatelliteNumber'
    xquery: |
      declare variable $node_platform external;
      data($node_platform/number)
  - name: 'platformIdentifier'
    python: |
      return node_platform['nssdcIdentifier'].value
  - name: 'resolutionDetail'
    python: |
      resolution = node.name[10:11]
      if resolution == 'F':
        return 'Full'
      elif resolution == 'H':
        return 'High'
      elif resolution == 'M':
        return 'Medium'
      return None
  - name: 'index_340_380'
    script: package.module:function1