Vocabulary functions

Scope

This page describes how to serve vocabulary translations using some function expressions in application schema mapping file. If you’re not familiar with application schema mapping file, read Mapping File.

Versions supported

This functionality is supported from GeoTools version 2.6-M2 onwards.

Useful functions

Recode function

This is similar to if_then_else function, except that there is no default clause. You have to specify a translation value for every vocabulary key.

Syntax:

Recode(COLUMN_NAME, key1, value1, key2, value2,...)
  • COLUMN_NAME: column name to get values from

Example:

<AttributeMapping>
  <targetAttribute>gml:name</targetAttribute>
  <sourceExpression>
      <OCQL>Recode(ABBREVIATION, '1GRAV', 'urn:cgi:classifier:CGI:SimpleLithology:2008:gravel',
                                 '1TILL', 'urn:cgi:classifier:CGI:SimpleLithology:2008:diamictite',
                                 '6ALLU', 'urn:cgi:classifier:CGI:SimpleLithology:2008:sediment')
      </OCQL>
  </sourceExpression>
</AttributeMapping>

The above example will map gml:name value to urn:cgi:classifier:CGI:SimpleLithology:2008:gravel if the ABBREVIATION column value is 1GRAV.

Categorize function

This is more suitable for numeric keys, where the translation value is determined by the key’s position within the thresholds.

Syntax:

Categorize(COLUMN_NAME, default_value, threshold 1, value 1, threshold 2, value 2, ..., [preceding/succeeding])

  • COLUMN_NAME: data source column name

  • default_value: default value to be mapped if COLUMN_NAME value is not within the threshold

  • threshold(n): threshold value

  • value(n): value to be mapped if the threshold is met

  • preceding/succeeding:
    • optional, succeeding is used by default if not specified.
    • not case sensitive.
    • preceding: value is within threshold if COLUMN_NAME value > threshold
    • succeeding: value is within threshold if COLUMN_NAME value >= threshold

Example:

<AttributeMapping>
  <targetAttribute>gml:description</targetAttribute>
  <sourceExpression>
      <OCQL>Categorize(CGI_LOWER_RANGE, 'missing_value', 1000, 'minor', 5000, 'significant')</OCQL>
  </sourceExpression>
</AttributeMapping>

The above example means gml:description value would be significant if CGI_LOWER_RANGE column value is >= 5000.

Vocab function

This is the new function Jody implemented, and more useful for bigger vocabulary pairs. Instead of writing a long key-to-value pairs in the function, you can keep them in a separate properties file. The properties file serves as a lookup table to the function. It has no header, and only contains the pairs in ‘’<key>=<value>’’ format.

Syntax:

Vocab(COLUMN_NAME, properties file URI)
  • COLUMN_NAME: column name to get values from
  • properties file URI: absolute path of the properties file or relative to the mapping file location

Example:

Properties file:

1GRAV=urn:cgi:classifier:CGI:SimpleLithology:2008:gravel
1TILL=urn:cgi:classifier:CGI:SimpleLithology:2008:diamictite
6ALLU=urn:cgi:classifier:CGI:SimpleLithology:2008:sediment

Mapping file:

<AttributeMapping>
  <targetAttribute>gml:name</targetAttribute>
  <sourceExpression>
      <OCQL>Vocab(ABBREVIATION, '/test-data/mapping.properties')</OCQL>
  </sourceExpression>
</AttributeMapping>

The above example will map gml:name to urn:cgi:classifier:CGI:SimpleLithology:2008:gravel if ABBREVIATION value is 1GRAV.

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