Geospatial Data and Metadata
Geospatial (or spatial) data is information specific to objects, events or other phenomena associated with a location on or near the surface of the Earth. Metadata describes that data.
Geospatial data combines:
- location information (usually coordinates on the Earth)
- attribute information (the characteristics of the object, event, or phenomena concerned)
- often temporal information (the time or life span at which the location and attributes exist).
Geospatial data can be static, such as the site of an earthquake, or dynamic like the spread of an infectious disease. It can even be collected inadvertently by digital cameras or GPS trackers and is usually shown numerically as coordinates.
Using Geospatial Data
The power of a geospatial ‘tag’ on any data lies in its ability to make connections to other research modes, types and even to seemingly unrelated things, including analysis of data collected at locations for different reasons and by different disciplines. One application for geospatial data is within a geographic information system (GIS) to understand spatial relationships and create maps describing these relationships.
Importance of Metadata
Metadata describes the data, within the data structure itself or separate from the data. This can help to facilitate and support resource discovery, identification, organisation of resources, and the interoperability of the resource(s) it represents, and of the metadata itself.
This is important, because despite the growing volume of geospatial data available from a variety of sources and the ease of identifying this data, finding and using this data is a challenge for researchers because of limited metadata.
For example, where data about an entity does not already contain geographic location information, metadata containing the geographic location information for that data can be constructed and either included within, or associated with the data – improving wider discovery and use.
More about metadata.
Data provenance is the documentation of where a piece of data comes from and the processes and methodology by which it was produced. Provenance answers the questions of why and how the data was produced, where, when and by whom.
More about data provenance.
FAIR Data Principles
The inclusion of metadata to enable the transfer or sharing of data is now a standard practice in spatial communities, satisfying FAIR data principles (Findable, Accessible, Interoperable, and Reusable) by both humans and machines. Metadata can ensure users of geospatial data are aware of its geographic information, limitations, restrictions and of its suitability for use in their research.
More about FAIR data principles.
Geospatial Data Formats
Specialised software applications, such as GIS software, can be used to access, manipulate, visualise and analyse geospatial data which can be stored and exchanged as:
- tabular data – e.g. csv or xlsx
- database (geo-specific or general)
- raster image – data represented as a grid of pixels with associated geographic information (JPG, GIR, PNH, TIF, PMP, PSD, GeoTIFF, COG)
- vector image (AI, CRD or SVG )
- shapefile – non-topological format containing location and geographic entity metadata
- coverage – a georelational data model that stores vector data consisting of location information and other geographic entity metadata (SHP SHX and DBF)
- OpenStreetMap OSM XML
- Digital Line Graph (DLG)
- OGC® GeoPackage Encoding Standard
Geospatial Metadata Standards
The international metadata standard ISO19115-1:2014 has been widely adopted for describing geographic information and services. It has been adopted for use within Australia and is the basis for the ANZLIC metadata profile.
ANZLIC – the Spatial Information Council is the peak intergovernmental organisation that provides leadership in the collection, management and use of spatial information in Australia and New Zealand. It developed the ANZLIC metadata profile (AS/NZS ISO19115-1:2015) to facilitate interoperability within and between Australian and New Zealand agencies and jurisdictions
ISO 19115-1:2-14 defines the schema required for describing geographic information and services by means of metadata. It provides information about the identification, the extent, the quality, the spatial and temporal aspects, the content, the spatial reference, the portrayal, distribution, and other properties of digital geographic data and services.
The ANZLIC metadata profile differs only in that it has a mandatory metadata identifier.
Explore these links for more information about geospatial data and metadata:
- The GDA Modernisation Implementation Working Group (GMIWG) which oversees the implementation of Geocentric Datum of Australia 2020.
- The Open Geospatial Consortium
- The Intergovernmental Committee on Surveying and Mapping (ICSM)
- The ANZ Metadata Working Group (MDWG) is a sub-committee of ICSM
- Permanent Committee on Geodesy which is responsible for managing the Australian Geospatial Reference System
- ANZLIC Committee on Survey and Mapping – basics of Datums
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