AIXM 5 Metadata Requirements for AIXM Metadata AIXM

AIXM 5 Metadata

• Requirements for AIXM Metadata • AIXM Metadata Model • Examples

Metadata • Metadata is structured information about data • It provides information about a particular dataset, which can be a message or a single feature – the origin of the data, the citation for the resources, an abstract, the purposes, credits, the status and points of contact

AIXM Requirements • AIXM has two high-level requirements: – Compliance with the ISO 19100 series – Coverage for AIXM specific needs • CRC • Integrity

Main Sources • International Standardization Organization (ISO) – 19115 (Geographic information – Metadata) and Corrigendum – 19139 (Geographic information – Metadata – XML Schema Implementation) • ISO 19139 = XML Schema based encoding for ISO 19115 metadata • Defines geographic metadata XML encoding (gmd. XML)

Main Sources • ISO 19115 UML model online: http: //www. isotc 211. org/ • ISO 19139 schema available at: http: //www. isotc 211. org/2005/

Suitability of ISO 19115 • ISO 19115 defines over 400 metadata elements • Answers: – – Does a dataset on a specific topic exist (‘what’)? For a specific location (‘where’)? For a specific date or period (‘when’)? A point of contact to learn more about or order the dataset (‘who’)? • Describes metadata for catalogue services, rather than for recurrent messages (e. g. AIXM messages)

• Requirements for AIXM Metadata • AIXM Metadata Model • Examples

AIXM Metadata Model • AIXM metadata model is based on ISO 19115 • However, it is not intended to be a substitution for ISO 19115 • It does not completely conform to ISO 19115

Differences • The AIXM metadata model: – Does not include topic category as mandatory – Includes extended metadata elements required to describe aeronautical information exchange data

Metadata Layers • The AIXM Metadata model provides Metadata at three levels: – For the entire dataset or package, i. e. AIXM message – For each feature within a message – For each timeslice within a feature

Metadata Layers

AIXM Metadata Profile • The profile has 6 models: – 1. Metadata for the AIXM message – 2. Metadata for an AIXM feature – 3. Metadata for an AIXM feature timeslice – 4. Constraint information – 5. Citation and Responsible Party information – 6. Data Quality information

Metadata to Include with AIXM Message • The classes named using prefix MD or CI or DQ indicate inclusion of, or association with, ISO 19115 classes

New Metadata Elements • cyclic. Redundancy. Check. Message is the value or string of alphanumeric characters usually generated by a cyclic redundancy check (CRC) algorithm. – Best practice recommends that the algorithm consider all tags and data elements within the feature data – When the data receiver applies the CRC algorithm to the feature data, a different CRC indicates that a tag or data element within the feature data has been changed since the sender generated the original CRC • note. CRCMessage provides the ability to relay information to the data receiver if necessary about the CRC calculation – Using this data element, the sender can document the tags and data elements considered in the cyclic redundancy check

Modified Metadata Elements • The Identification. Message outlines the elements to include as it pertains to the data in the AIXM message • The relationships with MD_Identification is labelled restriction since the AIXM class is a subset of and/or includes varied attributes • Identification. Message and Message. Metadata are related to MD_Constraints

Constraint Information Metadata

New Constraint Roles • Constraints manage the rights to information including restrictions on access and use. • message. Constraint. Info describes the constraints – If any of the features within the message have attributes with classification codes such as restricted, confidential, top secret, etc. , the classification code for the feature captures the highest classification code among the attributes – message. Constraint. Info captures the highest classification code among the features • metadata. Constraint. Info describes any restrictions on the access and use of the metadata for the AIXM message – Classification code for this role is determined by the sender or data producer • Both are similar to the role metadata. Constraints relating MD_Metadata to MD_Constraints in ISO 19115

Metadata to Include About an AIXM Feature • Similar to metadata on a Message: – cyclic. Redundancy. Check. Feature – note. CRCFeature

Metadata to Include About an AIXM Feature Timeslice

Metadata Elements • The Feature. Time. Slice. Metadata class includes elements: – to reference the party responsible for the metadata information – the date on which the metadata was compiled. • Feature. Time. Slice. Metadata contains five new metadata elements not defined in ISO 19115: – – – measure. Class meas. Equip. Class data. Integrity horizontal. Resolution vertical. Resolution

Citation and Responsible Party Information Metadata

Similar to ISO 19115 • Describes authoritative reference information • Responsible. Party is essentially the same as ISO 19115 CI_Responsible. Party – except two new data elements: • system. Name as a place to describe the responsible system, i. e. , database or repository • digital. Certificate, a field to capture an electronic signature authentication information – contact. Info is associated with Contact not CI_Contact • The Contact class differs from ISO 19115 CI_Contact class. – address is the same as in ISO 19115 which maps to the CI_Address class – phone maps to the class Telephone not to CI_Telephone

Data Quality Information Metadata

Description • Describes the quality of data within a feature timeslice. • The quality of data may vary by attribute or set of attributes. – ISO 19115 data element attributes is used to list the attributes to which the report applies. • report maps to class Data. Quality. Element associated with DQ_Element which contains – ISO 19115 elements evaluation. Method. Description and pass. – a new metadata element evaluation. Method. Name giving the name of the evaluation method used on the given attributes (Air. MAT-AICM metadata harmonization)

• Requirements for AIXM Metadata • AIXM Metadata Model • Examples

Optional • It is optional to include metadata within an AIXM message or feature timeslice • If it is included, it should conform to the profile • Metadata can be easily captured and it is highly recommended that it be sent with an AIXM message

Mandatory Message Metadata <Message. Metadata> <date. Stamp>2007 -09 -11 T 16: 00 Z</date. Stamp> <contact> <individual. Name>Scott Wilson</individual. Name> <position. Name>AIXM Development Support</position. Name> <role>distributor</role> </contact> <message. Identification. Info> <abstract>“baseline” timeslice valid 01 Jan 2008</abstract> <language>en</language> </message. Identification. Info> </Message. Metadata>

Feature Timeslice Metadata <Feature. Time. Slice. Metadata> <date. Stamp>2007 -09 -11 T 16: 00 Z</date. Stamp> <contact> <organization. Name>EUROCONTROL</organization. Name> <position. Name>AIXM Development</position. Name> <role>originator</role> </contact> <feature. Identification. Info> <abstract>Donlon antenna</abstract> <citation> <title>Metadata study</title> <date>2007 -09 -10 T 17: 00 Z</date> <date. Type>revision</date. Type> </citation> </feature. Identification. Info> </Feature. Time. Slice. Metadata>

Current Status • The AIXM Metadata Model has not been applied to the XML Schema in Release Candidate 2 • RC 2 uses the ISO 19139 Schemas • Release Candidate 3 will consider the adoption of the profile

Next Steps • The final AIXM 5 release will provide guidelines on how certain metadata fields shall be used • This will lead to harmonised encodings of certain information, such as – accountable source, – date when the information was issued, – contact details, etc.

Metadata Forms • http: //geonetwork-opensource. org/

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