Technical Committee 211 of the International Standards Organization (ISO) has defined a series of standards for geographic metadata and services. Many of these standards are closely related to and compatible with OGC Standards. These standards are currently being adopted across the NASA Earth Science community and by many partners in the U.S. and around the world.
ISO 19115 is the primary metadata standard in the ISO TC211 Collection. The objective of ISO 19115 is to provide a structure for describing digital geographic data. It defines metadata elements, provides a schema (ISO 19139) and establishes a common set of metadata terminology, definitions, and extension procedures. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data.
ISO 19115 defines:
The MD_Metadata package defines the schema for describing the complete metadata about a resource (DS_Resource) and metadata about the metadata itself.
Identification information supports the provision of information to uniquely identify a resource. MD_Identification can be specified as MD_DataIdentification or SV_ServiceIdentification and is an aggregate of eight classes of metadata which aid in resource identification.
This package supports the provision of metadata concerning the legal and security constraints placed on resources. It consists of MD_Constraints which can be specified as MD_LegalConstraints and/or MD_SecurityConstraints.
For more detailed information, see the page on ISO 19157.
This package supports the provision of metadata concerning the sources and production processes used in producing a resource. The DQ_DataQuality class is defined in ISO 19157. LI_Lineage is defined in 19157 while LE_Lineage is defined in 19115-2.
This package supports the provision of metadata related to the scope and frequency of maintenance for a resource.
This package supports the provision of metadata identifying the spatial primitives used by a resource; the mechanisms used to model real world phenomena in a digital information system. It consists of the MD_SpatialRepresentation which can be specified as either MD_VectorSpatialRepresentation or MD_GridSpatialRepresentation which can be further specified as MD_Georectified or MD_Georeferencable.
This package supports the metadata identifying the spatial and temporal reference system(s) used by a resource.
This package supports the provision of metadata identifying the content of a resource by: citing the feature catalog used to define the content (MD_FeatureCatalogueDescription); incorporating the feature catalogue (MD_FeatureCatalogue – defined in ISO 19110); or describing the content of a coverage resource (MD_CoverageDescription) which also may be specified as MD_ImageDescription.
The portrayal catalogue describes how the resource can be rendered for human visualisation.
This package supports the provision of metadata about the distributor of, and options for obtaining, a resource.
This package supports the provision of information about user specified metadata extensions.
This package supports the provision of metadata describing the application schema used to define and expose the structure of a resource.
The a combination of documentation packages used to describe metadata or data services. The structure of service metadata includes three major classes: a section of basic service metadata (SV_ServiceIdentification class) that provides a general description of the service and two sections that describe the operations (SV_OperationMetadata) and data (MD_DataIdentification) available from a particular service.
The datatype in this package is an aggregate of the metadata elements that describe the spatial and temporal extent of resources, objects, events, or phenomena. The EX_Extent class contains information about the geographic (EX_GeographicExtent), temporal (EX_TemporalExtent) and the vertical (EX_VerticalExtent) extent of something.
This package provides a standardized method for citing a resource, as well as information about the party responsible for a resource. Citations use CI_Citation and cite the party responsible by aggregating CI_ResponsiblePartyInfo.
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ISO 19115-2, "Geographic information -- Metadata -- Part 2: Extensions for imagery and gridded data" is an extension for ISO 19115 and includes information on data properties, geospatial characteristics, processing and acquisition methods. It is anticipated that features of 19115-2 and 19115-1 may merge at some point in the future.
The ISO 19115-2:2009 standard extends the existing geographic metadata standard by defining the schema required for describing imagery and gridded data. It provides information about the properties of the measuring equipment used to acquire the data, the geometry of the measuring process employed by the equipment, and the production process used to digitize the raw data. This extension deals with metadata needed to describe the derivation of geographic information from raw data, including the properties of the measuring system, and the numerical methods and computational procedures used in the derivation. The metadata required to address coverage data in general is addressed sufficiently in the general part of ISO 19115.
Resource Fact Sheet: http://www.isotc211.org/Outreach/Overview/Factsheet_19115-2.pdf
ISO 19115-2 extends ISO 19115 specifically for imagery and gridded data. These extensions also allow for the documentation of data collected via instrumentation. The root of ISO 19115 metadata records will change from MD_Metadata to MI_Metadata when using ISO 19115-2. A new section is also added, gmi:acquisitionInformation includes the new packagage, MI_AcquisitionInformation.
Figure 1: and the relationship to MD_Metadata.
In comparison with ISO 19115, ISO 19115-2 offers multiple extensions and imagery-specific modifications. These include:
QE_CoverageResult provides a means to document the quality associated with coverages (as defined by MD_Format).
LE_Lineage adds additional lineage/quality information relating to:
QE_Usability provides a means to documents the utility of a data entity relative to a user's requirements.
MI_Georectified (includes information to allow for the geolocational validation of gridded data), MI_Georeferenceable (extends the 19115 class to include information that can be used to geolocate raster imagery) and the associated classes comprise extensions required to specify the spatial representation for imagery and gridded data.
Provides information relevant to the quality of GCPs.
19115-2 provides extensions to allow for description of the content of imagery and gridded data datasets.
Acquisition Overview pertains to the metadata classes required to define the acquisition of imagery and gridded datasets.
Acquisition Details contains means to document the specific acquisition of imagery and gridded datasets.