Configuring faceted search

Facets also known as aggregation in Elasticsearch are used to provide simple search entries. GeoNetwork is using facet in different places:

• Home page categories

• Search results

All facet configurations are stored in the user interface configuration (see User Interface Configuration). The configuration are defined using JSON following Elasticsearch API (See https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket.html).

By default, the facet configurations are defined as (see source file web-ui/src/main/resources/catalog/js/CatController.js). The home page display on the left side inspireThemeUri and topic_text and on the right side, the last facet defined codelist_hierarchyLevel_text.

Simple aggregation on a field:

"cl_hierarchyLevel.key": {
  "terms": {
    "field": "cl_hierarchyLevel.key"
  }
}

For codelist, use .default for not multilingual catalogue with one language only UI.

"cl_spatialRepresentationType.default": {
   "terms": {
     "field": "cl_spatialRepresentationType.default",
     "size": 10
   }
 },

Use .key for codelist for multilingual catalogue. The codelist translation needs to be loaded in the client app. See GnSearchModule.js.

"cl_spatialRepresentationType.key": {
     "terms": {
       "field": "cl_spatialRepresentationType.key",
       "size": 10
     }
   },

GEMET configuration for non multilingual catalog default property contains the default language so if all records have in the same language there is no mix of languages. In the user interface, this language is displayed.

"th_gemet_tree.default": {
  "terms": {
    "field": "th_gemet_tree.default",
    "size": 100,
    "order" : { "_key" : "asc" },
    "include": "[^\^]+^?[^\^]+"
    // Limit to 2 levels
  }
},

If records are not all in all the same languages, languages can be mixed together.

GEMET configuration for multilingual catalog. The key is translated on client side by loading required concepts using the thesaurus API.

"th_gemet_tree.key": {
  "terms": {
    "field": "th_gemet_tree.key",
    "size": 100,
    "order" : { "_key" : "asc" },
    "include": "[^\^]+^?[^\^]+"
    // Limit to 2 levels
  }
}

With the key, french and english translations are considered equivalent.

Aggregation based on queries. One query will define one bucket in the aggregation.

"availableInServices": {
  "filters": {
    //"other_bucket_key": "others",
    // But does not support to click on it
    "filters": {
      "availableInViewService": {
        "query_string": {
          "query": "+linkProtocol:/OGC:WMS.*/"
        }
      },
      "availableInDownloadService": {
        "query_string": {
          "query": "+linkProtocol:/OGC:WFS.*/"
        }
      }
    }
  }
}

Key like availableInViewService may not be available in the translations. Use the translation API to add your custom translation in the database.

To enable filtering in a facet, add an include property:

"tag.default": {
  "terms": {
    "field": "tag.default",
    "include": ".*",
    "size": 10
  }
}

include and exclude properties can be used to filter values too.

Aggregations can be collapsed by default and visible to users depending on roles:

"dateStamp" : {
   "userHasRole": "isReviewerOrMore",
   "collapsed": true,
   "auto_date_histogram" : {
     "field" : "dateStamp",
     "buckets": 50
   }

(Experimental) A tree field which contains a URI eg. http://www.ifremer.fr/thesaurus/sextant/theme#52 but with a translation which contains a hierarchy with a custom separator /Regulation and Management/Technical and Management Zonations/Sensitive Zones

"th_sextant-theme_tree.key": {
  "terms": {
    "field": "th_sextant-theme_tree.key",
    "size": 100,
    "order" : { "_key" : "asc" }
  },
  "meta": {
    "translateOnLoad": true,
    "treeKeySeparator": "/"
  }
}

The search results facets configuration is defined in the search section and contains various examples of what you can do using facets:

• Nested facets

• Facet based on filter

• Use order to sort facets

• Use include to limit values

• Use collapsed to collapse the item on load

• Use “userHasRole”: “isReviewerOrMore”, to display facet depending on user roles

• Use field ending with _tree to hierarchy mode

'facetConfig': {
   'codelist_hierarchyLevel_text': {
     'terms': {
       'field': 'codelist_hierarchyLevel_text'
     },
     'aggs': {
       'format': {
         'terms': {
           'field': 'format'
         }
       }
     }
   },
   'codelist_spatialRepresentationType': {
     'terms': {
       'field': 'codelist_spatialRepresentationType',
       'size': 10
     }
   },
   'availableInServices': {
     'filters': {
       //"other_bucket_key": "others",
       // But does not support to click on it
       'filters': {
         'availableInViewService': {
           'query_string': {
             'query': '+linkProtocol:/OGC:WMS.*/'
           }
         },
         'availableInDownloadService': {
           'query_string': {
             'query': '+linkProtocol:/OGC:WFS.*/'
           }
         }
       }
     }
   },
   'th_gemet_tree': {
     'terms': {
       'field': 'th_gemet_tree',
       'size': 100,
       "order" : { "_key" : "asc" },
       "include": "[^\^]+^?[^\^]+"
       // Limit to 2 levels
     }
   },

Currently supported aggregations are:

• terms

• filters

• histogram

"resolutionScaleDenominator": {
  "histogram": {
    "field": "resolutionScaleDenominator",
    "interval": 10000,
    "keyed" : true,
    "min_doc_count": 1
  }
},
"creationYearForResource": {
  "histogram": {
    "field": "creationYearForResource",
    "interval": 5,
    "keyed" : true,
    "min_doc_count": 1
  }
},