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Table of contents

  1. How fields are named
  2. Fields related to identity
  3. Custom fields

See the current schema for a full description of fields, expected values, and obligations.

How fields are named


Solr uses the suffix of a metadata element to determine what kind of field it is. The following suffixes are part of the OGM Aardvark schema and may be used by custom fields, too (for a full list of spatial field types and their suffixes, see this code):

Field Suffix Type Description Example
_b Boolean Values can be “TRUE” or “FALSE” gbl_georeferenced_b
_im Integer, multi-valued Digits gbl_indexYear_im
_drsim Date range, multi-valued Date range in a specified format: “[1980 TO 1995]” gbl_dateRange_drsim
_dt Date Date and time in a specified format: YYYY-MM-DDThh:mm:ssZ gbl_mdModified_dt
_s String Single string of text dct_title_s
_sm String, multi-valued Multiple strings of text dct_subject_sm

Altering suffixes can result in metadata schema incompatibilities across institutions. Any deviations in element names causes Solr to treat the elements as separate fields: for example dct_subject_s and dct_subject_sm would be stored separately. If GeoBlacklight is set up to display a facet for dct_subject_s, it will not pick up values stored in dct_subject_sm in the filter. Therefore, if you are gathering metadata from other institutions, make sure to inspect their metadata fields to determine if there will be inconsistencies in your Solr index.

There are three fields that relate to a layer’s identity.

WxS Identifier
OGM Aardvark: gbl_wxsIdentifier_s
GBL 1.0: layer_id_s

This field is used to identify the layer or store for a WFS, WMS, or WCS web service so GeoBlacklight can construct the full web service link. It should point to a specific layer within an OGC geospatial web service. This value is only used when you have WxS services listed in your references field (dct_references_s). Examples:

  • UCB:elev_100ft_polygon
  • aa111bb2222

OGM Aardvark: id
GBL 1.0: layer_slug_s

This field makes up the URL for the resource in GeoBlacklight. It is visible to the user and is used to create permalinks. The value should be alpha-numeric characters separated by dashes. If having a readable slug is desired, it is common to use the form institution-keyword1-keyword2. It should also be globally unique across all institutions in your GeoBlacklight index. Examples:

  • india-map
  • stanford-andhra-pradesh-village-boundaries
  • stanford-aa111bb2222

OGM Aardvark: dct_identifer_sm
GBL 1.0: dc_identifier_s

This is a general purpose field that can contain one or more persistent identifers or permalinks, as well as other identifiers like DOIs, catalog numbers, and/or other system numbers. It is not visible in the GeoBlacklight interface. Examples:

  • 5864 .L7 E635 1998 .G7

Custom fields

If an organization wishes to implement a custom metadata field for their GeoBlacklight instance, the naming schema should reference the organization as follows: organization_elementName_solrFieldType.


  • b1g_code_s - Internal code that organizes items by their source collection
  • nyu_addl_dspace_s - A 5 digit number that is the “internal identifier” for DSpace, the repository software that mints handles for all NYU’s items. The internal id must be paired with the handle in order to post metadata and data via the system API.