ISO 19115-2:2009 Geographic information - Metadata - Part 2: Extensions for imagery and gridded data
|Full name||ISO 19115-2:2009, Geographic information – Metadata – Part 2: Extensions for imagery and gridded data|
|Published by||ISO/TC 211|
|Type of standard||ISO International Standard
|Application||The standard specifies how to document metadata for imagery and gridded data, which includes information on data quality, lineage, etc.|
This part of ISO 19115 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.
ISO 19115-2:2009 is an extension of ISO 19115:2003, Geographic information – Metadata, defining metadata for imagery and gridded data. As such, it needs to be used in conjunction with ISO 19115:2003, as the latter defines the metadata for the dataset in general and for coverages in general. ISO 19115-2:2009 defines the metadata for the measuring equipment used to acquire the data (such as a satellite-borne sensor), the geometry of the acquisition and the production processes to produce the dataset.
As the revision of ISO 19115:2003, namely ISO 19115-1:2014, Geographic information – Metadata – Part 1: Fundamentals, has now been published, ISO 19115-2:2009 will need to be revised to benefit from ISO 19115-1:2014. The current version of ISO 19115-2:2009 will be deprecated when its revision is published, but will still be available because of the masses of legacy metadata conforming to ISO 19115-2:2009.
Implementing ISO 19115-2:2009 is essentially the same as implementing ISO 19115:2003 and it is also supported by a wide variety of proprietary and open-source GISs and stand-alone and web-based metadata editors. Note that ISO 19115-2:2009 refers to quality elements defined in ISO 19115:2003 and when ISO 19115-2:2009 is revised, these will refer to the quality elements now in ISO 19157:2013. To the metadata packages, entities and elements defined in ISO 19115:2003, ISO 19115-2:2009 adds the following:
- Metadata entity set – Imagery: the package MI_Metadata are for the acquisition information for the imagery or gridded data.
- Data quality information: imagery, coverage result, lineage and usability. For the imagery coverage result, QE_CoverageResult consists of the spatial representation, coverage description and data format, which are all defined in ISO 19115:2003. This is necessary because the actual spatial representation of the imagery or gridded data might differ from that of its related coverage (e.g. if the coverage is computed from a subset of the whole dataset). This is coupled with MX_DataFile, which is defined in ISO 19139:2007, Geographic information – Metadata – XML schema implementation, and is a description of the transfer dataset in XML. For usability, QE_Useability specifies the degree of adherence of the dataset to a specific set of user requirements. For the extensions to lineage, there are six new classes specified: LE_Source (input and output datasets), LE_ProcessStep (the event or transformation of the process step from one version of the dataset to the next), LE_ProcessStepReport (the report produced by the process step), LE_Processing (the procedures, processes and algorithms applied during the process step), LE_Algorithm (methodology for obtaining geospatial data from the instrument readings) and LE_NominalResolution (scanning and ground resolution).
- Spatial representation information – Imagery: extension to georectified and georeferenceable classes, and ground control point quality. MI_GCP specifies a ground control point, which can have its data quality specified using the data quality elements in ISO 19115:2003. MI_GCPCollection is then a designated set of GCPs, which MI_GeolocationInformation uses to determine geographic location corresponding to image location. MI_Georeferenceable uses MI_GeolocationInformation to allow the geographic or map locations of the raster points to be located. MI_Georectified uses MI_GCP to provide checkpoints.
- Content information – Imagery: further details of the coverage, imagery, band, polarisation, transfer function and range element. MI_Band provides details of the wavelength band, its boundaries, nominal spatial resolution, transfer function for scaling, and transmitted and detected polarization. MI_CoverageDescription and MI_ImageDescription describe the specific range elements of the coverage and image respectively, using MI_RangeElementDescription, which names and describes the range elements (the range of a sensor is across its track, so the elements in the range should be the same for each sweep of the sensor).
Acquisition information – Imagery: further details of the platform, plan, instrument, operation, environmental record, objective and requirement. MI_EnvironmentalRecord documents the air temperature, relative humidity, maximum altitude and other meteorological conditions for photo flights. MI_Event documents the trigger, context, sequence and time of a significant collection point for an objective and pass of an instrument. MI_Instrument documents a particular instrument. MI_Objective documents the priority, type, function, spatial and temporal extents, and events of a target for a pass of an instrument. MI_Operation documents the status, type and other details of the plan and platform for an operation, including its relationships with possible child and parent operations. MI_Plan documents the type, status and authority of a plan, the activities that satisfy the plan and the requirement satisfied by the plan. MI_Platform documents a platform, including its sensors and sponsor. MI_PlatformPass documents the collection coverage of a pass. MI_RequestedDate documents the preferred and latest date and time for a desired collection. MI_Requirement documents the requirements to be satisfied by the planned data acquisition, including the requestor, recipient, priority and dates.