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References

Label References
URI dct_references_s
Obligation Recommended
Multivalued false
Field type string (serialized JSON)
Purpose To provide external URLs for accessing or describing the resource
Entry Guidelines This field defines external services and references using the CatInterOp approach. The field value is a serialized JSON array of key/value pairs, with keys representing namespace URI’s and values the URL.
Commentary All of the external links for the resource are added to This field as a serialized JSON array of key/value pairs. The download key/value pair is unique, because the value can be an array.
Controlled Vocabulary no
Example value "{\"http://schema.org/url\":\"http://purl.stanford.edu/bm662dm5913\",
\"http://schema.org/downloadUrl\":\"http://stacks.stanford.edu/file/druid:bm662dm5913/data.zip\"}"
Element Set DCMI
Group Distribution

JSON formatting

The field dct_references_s defines external services and references using the Cat-Interop approach. The field value is a serialized JSON array of key/value pairs. Keys represent XML namespace URIs, and values represent the URL.

  • key:value 1 = “URI”:”https://example.com”
  • key:value 2 = “URI”:”https://otherexample.com”

To format this field in JSON, double quotations " must be escaped with a backslash \.

{
  "dct_references_s": "{
    \"http://schema.org/url\":\"http://purl.stanford.edu/bm662dm5913\",
    \"http://schema.org/downloadUrl\":\"http://stacks.stanford.edu/file/druid:bm662dm5913/data.zip\"
    }"
}

Reference URIs

These are URIs that can be used as keys in the dct_references_s field.

Type Reference URI Function in GeoBlacklight
Download data dictionary / documentation http://lccn.loc.gov/sh85035852 Link to download documentation
Download file http://schema.org/downloadUrl Link to download file (for multiple download links, see below
Full layer description http://schema.org/url View further descriptive information about the layer
International Image Interoperability Framework (IIIF) Image API http://iiif.io/api/image Load the image viewer using Leaflet-IIIF
International Image Interoperability Framework (IIIF) Presentation API Manifest http://iiif.io/api/presentation#manifest View the IIIF manifest
Metadata in FGDC http://www.opengis.net/cat/csw/csdgm View structured metadata in FGDC standard expressed as XML
Metadata in HTML http://www.w3.org/1999/xhtml View structured metadata in any standard expressed as HTML
Metadata in ISO 19139 http://www.isotc211.org/schemas/2005/gmd/ View structured metadata in ISO standard expressed as XML
Metadata in MODS http://www.loc.gov/mods/v3 View structured metadata in MODS format
OpenIndexMap https://openindexmaps.org Provide an index map preview
Web Mapping Service (WMS) http://www.opengis.net/def/serviceType/ogc/wms Link to preview layer, inspect features, and download data (vector: KMZ, raster: GeoTIFF)
Web Feature Service (WFS) http://www.opengis.net/def/serviceType/ogc/wfs Link to download vectors (GeoJSON, shapefile)

ArcGIS URIs

Type Reference URI Function in GeoBlacklight
ArcGIS FeatureLayer urn:x-esri:serviceType:ArcGIS#FeatureLayer Preview an ArcGIS FeatureLayer Service
ArcGIS TiledMapLayer urn:x-esri:serviceType:ArcGIS#TiledMapLayer Preview an ArcGIS TiledMapLayer Service
ArcGIS DynamicMapLayer urn:x-esri:serviceType:ArcGIS#DynamicMapLayer Preview an ArcGIS DynamicMapLayer Service
ArcGIS ImageMapLayer urn:x-esri:serviceType:ArcGIS#ImageMapLayer Previews a ArcGIS ImageMapLayer Service

URIs for specific institutions

Type Reference URI Function in GeoBlacklight
Harvard Geospatial Library email download http://schema.org/DownloadAction Retrieve a file via email from the Harvard Geospatial Library

Beginning with GeoBlacklight version 3.0, multiple download links and file formats can be included in the dct_references_s field. For more details on this update, see this pull request.

To enable multiple downloads:

  • Make the value for the download file URI (http://schema.org/downloadUrl) into an array. This means it is enclosed in [square brackets].
  • Create one or more objects inside the array. These are enclosed in {curly brackets}.
  • Inside the object, define two key:value pairs separated by a comma.
  • Enclose each key and each value in double quotes.
  • Escape double quotations " with a backslash \

In formatted JSON, this would look like:

{
  "dct_references_s": "{\"http://schema.org/downloadUrl\":[
    {
      \"url\":\"https://example.com\",
      \"label\":\"Shapefile\"
    },
    {
      \"url\":\"https://otherexample.com\",
      \"label\":\"KMZ\"
    }]
  }"
}

Examples

For an exmaple of a complete JSON file with multiple downloads, see this record.

Single download

{
  "dct_references_s": "{\"http://schema.org/downloadUrl\":\"https://cugir-data.s3.amazonaws.com/00/79/50/cugir-007950.zip\"}"
}

Single download as an array

When using an array for downloads, the value after the "label" key will be used as the text in the Download panel button.

{
  "dct_references_s": "{\"http://schema.org/downloadUrl\":[
    {
      \"url\":\"https://cugir-data.s3.amazonaws.com/00/79/50/cugir-007950.zip\",
      \"label\":\"Shapefile\"
    }]
  }"
}

Multiple downloads

{
  "dct_references_s": "{\"http://schema.org/downloadUrl\":[
    {
      \"url\":\"https://cugir-data.s3.amazonaws.com/00/79/50/cugir-007950.zip\",
      \"label\":\"Shapefile\"
    },
    {
      \"url\":\"https://cugir-data.s3.amazonaws.com/00/79/50/agBROO.pdf\",
      \"label\":\"PDF\"
    },
    {
      \"url\":\"https://cugir-data.s3.amazonaws.com/00/79/50/agBROO2011.kmz\",
      \"label\":\"KMZ\"
    }]
  }"
}