ICSM ISO19115-1 Metadata Best Practice Guide

Geographic Extent ★★★★

To quickly determine the general location of spatial features included in a cited resource it is useful that the extent information is provided in such a way so that the geographical extent of the resource can be easily understood.

   
Element Name geographicElement
Parent MD_Metadata.identificationInfo>MD_Identification.extent
Class/Type EX_GeographicExtent
Governance Common ICSM, Domain
Purpose Discovery
Audience machine resource - ⭑ ⭑ ⭑ ⭑
  general - ⭑ ⭑ ⭑ ⭑
  resource manager - ⭑ ⭑
  specialist - ⭑ ⭑ ⭑ (higher if domain specific placenames are used)
Metadata type descriptive
ICSM Level of Agreement ⭑ ⭑ ⭑

Definition

A description of the spatial area of the resource. These may be of the type Bounding Box, Geographic Description, or Bounding Polygon.

ISO Obligation

Discussion

Every metadata record describing geographic resources should contain descriptions that explain the area of interest of the resource. These may be in the form of place names, bounding box coordinate values and lastly, bounding polygons. With these, those searching for resources can be provided with a quick visual of the usable location of the resource. Catalogue software can use these descriptions to analyse and narrow searches to particular areas of interest.

The use of multiple geographic extents is recommended for more complicated geometries, including exclusion areas.

As these extents are meant to be used to give a general rough comparison to other geospatial data from sources, coordinates values should be captured in WGS 84 (EPSG 4326)

ICSM Best Practice Recommendations

Therefore - it is strongly recommended that to support the discovery of resources, every metadata record that describes a geographic resource contains geographic descriptions of the area of interest for the resource. At a minimum one description needs be in bounding box coordinate values. If there be any exclusion areas, the use of the boolean extentTypeCode (set to “0”) is recommended.

The MDWG recommends populating as many instances of Geographical Extent packages as needed to give a common understanding of the spatial coverage of the cited resource.

EX_GeographicExtent is an abstract class that is expressed by one of the three options

Also Consider

Other Discussion

data.gov.au guidance Free text with a mandatory requirement to use one of the following:

Crosswalk considerations

Dublin core / CKAN / data.gov.au

Maps to jurisdiction or geospatial coverage

DCAT

Maps to dct.spatial

RIF-CS

Maps to Coverage/Spatial

Examples

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UML diagrams

Recommended elements highlighted in yellow

geographicExtent

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