Geospatial metadata

Geospatial metadata (also geographic metadata, or simply metadata when used in a geographic context) is a type of metadata that is applicable to objects that have an explicit or implicit geographic extent, in other words, are associated with some position on the surface of the Globe. Such objects may be stored in a geographic information system (GIS) or may simply be documents, datasets, images or other objects, services, or related items that exist in some other native environment but whose features may be appropriate to describe in a (geographic) metadata catalogue (may also be known as a data directory, data inventory, etc.).

Definition

ISO 19115 "Geographic Information - Metadata" from ISO/TC 211, the current "best practice" standard for geospatial metadata, does not in fact provide a definition of Geospatial (or geographic) metadata(metadata); however, uses the following wording in its "scope" section:

"This International Standard provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data."

A little further, it is stated: "Though this International Standard is applicable to digital data, its principles can be extended to many other forms of geographic data such as maps, charts, and textual documents as well as non-geographic data."

The U.S. FGDC (Federal Geographic Data Committee) describes (geospatial) metadata as follows:

"A metadata record is a file of information, usually presented as an XML document, which captures the basic characteristics of a data or information resource. It represents the who, what, when, where, why and how of the resource. Geospatial metadata are used to document geographic digital resources such as Geographic Information System (GIS) files, geospatial databases, and earth imagery. A geospatial metadata record includes core library catalog elements such as Title, Abstract, and Publication Data; geographic elements such as Geographic Extent and Projection Information; and database elements such as Attribute Label Definitions and Attribute Domain Values."

History

The growing appreciation of the value of geospatial metadata through the 1980s and 1990s led to the development of a number of initiatives to collect metadata according to a variety of formats either within agencies, communities of practice, or countries/groups of countries. For example, NASA's "DIF" metadata format was developed during an Earth Science and Applications Data Systems Workshop in 1987, and formally approved for adoption in 1988. Similarly, the U.S. FGDC developed its geospatial metadata standard over the period 1992–1994. The Spatial Information Council of Australia and New Zealand (ANZLIC), a combined body representing spatial data interests in Australia and New Zealand, released version 1 of its "metadata guidelines" in 1996. ISO/TC 211 undertook the task of harmonizing the range of formal and de facto standards over the approximate period 1999–2002, resulting in the release of ISO 19115 "Geographic Information - Metadata" in 2003. As of 2011 individual countries, communities of practice, agencies, etc. have started re-casting their previously-used metadata standards as "profiles" or recommended subsets of ISO 19115, optionally with the inclusion of additional metadata elements as formal extensions to the ISO standard. The growth in popularity of Internet technologies and data formats, such as Extensible Markup Language (XML), during the 1990s led to the development of mechanisms for exchanging geographic metadata on the Web. In 2004, the Open Geospatial Consortium released the current version (3.1) of Geography Markup Language (GML), an XML grammar for expressing geospatial features and corresponding metadata. With the growth of the Semantic Web in the 2000s, the geospatial community has begun to develop ontologies for representing semantic geospatial metadata. Some examples include the Hydrology and Administrative ontologies developed by the Ordnance Survey in the United Kingdom.

ISO 19115: Geographic information - Metadata

ISO 19115 is a standard of the International Organization for Standardization (ISO). The standard is part of the ISO geographic information suite of standards (19100 series). ISO 19115 and its parts defines how to describe geographical information and associated services, including contents, spatial-temporal purchases, data quality, access and rights to use.

The objective of this International Standard is to provide a clear procedure for the description of digital geographic datasets so that users will be able to determine whether the data in a holding will be of use to them and how to access the data. By establishing a common set of metadata terminology, definitions and extension procedures, this standard will promote the proper use and effective retrieval of geographic data.

ISO 19139 Geographic information Metadata XML schema implementation

ISO 19139 provides the XML implementation schema for ISO 19115 specifying the metadata record format and may be used to describe, validate, and exchange geospatial metadata prepared in XML.

The standard is part of the ISO geographic information suite of standards (19100 series), and provides a spatial metadata XML (spatial metadata eXtensible Mark-up Language (smXML)) encoding, an XML schema implementation derived from ISO 19115, Geographic information – Metadata. The metadata includes information about the identification, constraint, extent, quality, spatial and temporal reference, distribution, lineage, and maintenance of the digital geographic dataset.

Metadata directories

Also known as metadata catalogues or data directories.

(need discussion of, and subsections on GCMD, FGDC metadata gateway, ASDD, European and Canadian initiatives, etc. etc.)

• GIS Inventory – National GIS Inventory System which is maintained by the US-based National States Geographic Information Council (NSGIC) as a tool for the entire US GIS Community. Its primary purpose is to track data availability and the status of geographic information system (GIS) implementation in state and local governments to aid the planning and building of statewide spatial data infrastructures (SSDI). The Random Access Metadata for Online Nationwide Assessment (RAMONA) database is a critical component of the GIS Inventory. RAMONA moves its FGDC-compliant metadata (CSDGM Standard) for each data layer to a web folder and a Catalog Service for the Web (CSW) that can be harvested by Federal programs and others. This provides far greater opportunities for discovery of user information. The GIS Inventory website was originally created in 2006 by NSGIC under award NA04NOS4730011 from the Coastal Services Center, National Oceanic and Atmospheric Administration, U.S. Department of Commerce. The Department of Homeland Security has been the principal funding source since 2008 and they supported the development of the Version 5 during 2011/2012 under Order Number HSHQDC-11-P-00177. The Federal Emergency Management Agency and National Oceanic and Atmospheric Administration have provided additional resources to maintain and improve the GIS Inventory. Some US Federal programs require submission of CSDGM-Compliant Metadata for data created under grants and contracts that they issue. The GIS Inventory provides a very simple interface to create the required Metadata.
• GCMD - Global Change Master Directory's goal is to enable users to locate and obtain access to Earth science data sets and services relevant to global change and Earth science research. The GCMD database holds more than 20,000 descriptions of Earth science data sets and services covering all aspects of Earth and environmental sciences.
• ECHO - The EOS Clearing House (ECHO) is a spatial and temporal metadata registry, service registry, and order broker. It allows users to more efficiently search and access data and services through the Reverb Client or Application Programmer Interfaces (APIs). ECHO stores metadata from a variety of science disciplines and domains, totalling over 3400 Earth science data sets and over 118 million granule records.
• GoGeo - GoGeo is a service run by EDINA (University of Edinburgh) and is supported by Jisc. GoGeo allows users to conduct geographically targeted searches to discover geospatial datasets. GoGeo searches many data portals from the HE and FE community and beyond. GoGeo also allows users to create standards compliant metadata through its Geodoc metadata editor.

Geospatial metadata tools

There are many commercial GIS or geospatial products that support metadata viewing and editing on GIS resources. For example, ESRI's ArcGIS Desktop, SOCET GXP, Autodesk's AutoCAD Map 3D 2008, Arcitecta's Mediaflux and Intergraph's GeoMedia support geospatial metadata extensively.

GIS Inventory is a free web-based tool that provides a very simple interface to create geospatial metadata. Participants create a profile and document their data layers through a survey-style interface. The GIS Inventory produces metadata that is compliant with the Federal Content Standard for Digital Geospatial Metadata (CSDGM). The GIS Inventory is also capably of ingesting already completed metadata through document upload and web server connectivity. Through the GIS Inventory web services, metadata are automatically shared with US Federal agencies.

GeoNetwork opensource is a comprehensive Free and Open Source Software solution to manage and publish geospatial metadata and services based on international metadata and catalog standards. The software is part of the Open Source Geospatial Foundation's software stack.

GeoCat Bridge allows to edit, validate and directly publish metadata from ArcGIS Desktop to GeoNetwork (and generic CSW catalogs) and publishes data as map services on GeoServer. Several metadata profiles are supported.

pycsw is an OGC CSW server implementation written in Python. pycsw fully implements the OpenGIS Catalogue Service Implementation Specification (Catalogue Service for the Web). The project is certified OGC Compliant, and is an OGC Reference Implementation.

CATMDEdit terraCatalog ArcCatalog ArcGIS Server Portal GeoNetwork opensource IME M3CAT MetaD MetaGenie Parcs Canada Metadata Editor Mapit/CADit NOKIS Editor

References

ANZLIC Metadata Profile Version 1.0 (viewed 17 Sept. 2007)

External links

• FGDC metadata page
• Global Change Master Directory(GCMD)
• Geospatial Exploitation of Motion Imagery is a geospatially aware and integrated Intelligent Video Surveillance (IVS) software system targeted at real-time and forensic video analytic and mining applications that require low-resolution detection, tracking, and classification of moving objects (people and vehicles) in outdoor, wide-area scenes.
• ISO 19115:2003 Geographic information -- Metadata
• Geographic information -- Metadata -- XML schema implementation
• EarthDataModels design for Metadata is a logical data model and physical implementation of a Spatial Metadata Database, based on ISO19115 and is INSPIRE compliant.