Interoperability A simple case for standards Kim Finney JCADM – Rome 2007

Data Exchange Scenario Instruments/Measurements Observations Local data store computer to computer communication

Data Exchange Scenario Which attributes can be considered to be capturing the same information ? CTD MeasurementsSeal Observations Project name Cruise Instrument type Principal Investigator name Quality control flags Depth/Temperature values Depth salinity values Latitude Longitude Ship Voyage Equipment Owner Depths Salinity/Temp/Oxygen Start position Stop position Species Abundance Age Weight Sex Location Mammal type Occurrence Size Age Male/Female Region

Data Exchange Scenario Note that the “data type” of the values can also be different? Seal Observations Species = Leptonychotes weddellii Abundance = 66 Age = five yrs Weight = 65 Sex = 20F30M Location = CS Mammal type = Weddell seal Occurrence = 67 Size = 56 Age = 4 Male/Female = 5:1 Region = E S

Data Exchange Scenario How do we know what units of measure, codes, CRS have been used ? Seal Observations Species = Leptonychotes weddellii Abundance = 66 (INDIVIDUALS) Age = five yrs old (AV. YEARS) Weight = 65 (AV. Kg) Sex = 20F30M (TOTAL OF EACH) Location = CS (PLACE NAME CODE) Mammal type = Weddell seal pups Occurrence = 67 (INDIVIDUALS) Size = 56 (cm AV. LENGTH) Age = 4 (AV. MONTHS) Male/Female = 5:1 (RATIO) Region = E S (LAT/LONG CRS)

Data Exchange Scenario Encodings and formatting patterns can also be very different ? Seal Observations L. Wedelli, 66, 5years, 65, 20F30M, CS L. Wedelli, 23, 2years, 64, 22F30M, CS L. Wedelli, 44, 5years, 54, 23F30M, CS L. Wedelli, 23, 3years, 56, 24F30M, CS L. Wedelli, 109, 2years, 68.4, 19F30M, CS Weddell seal :1 4: E S

Semantics Collaborators need to be able to agree on: –The definitions of the real-world objects to be exchanged Weddell Seal pups ? Seals ? Marine mammals ? Leptonychotes weddellii ? All of the above ?

Including attributes –How to model the characteristics of these real-world objects

Encoding –How to encode representations of these real-world objects to exchange them in cyberspace so that machines – not just humans can interpret their meaning. Leptonychotes weddellii weddell seal 12Jan F 76 8

Reference Systems Standard ways of representing real world object geometry or at least declare reference systems. e.g. Swath data e.g. Radar data

–Declaration of units of measure –Standard ways of representing location

Controlled Vocabularies Dictionaries of terms –Term, textual definition –Ranges, permissible codes, units of measure (optional) Ontologies –As above but includes relationships between terms and rules (axioms).

Ontologies Many definitions –A shared and common understanding of a domain that can be communicated between people and across application systems (Gruber, 1993). Classes or concepts => Sub-classes => Properties or slots => individual class is instance of Sub-class class is part of individual property has value of class property restricts Relationships

Semantic Interoperability Symbology Catalogue use Feature Catalogue Semantics Encodings Symbols Protocols

Common Patterns Feature Catalogue Feature Catalogue –Stores definitions of features (objects) & information about their attributes & relationships between features (semantics). CTD Profile {Feature} Position Bottom Depth Depth Parameter Feature Attributes Project {Feature} Project Name Project Description Platform {Feature} Platform Type Platform Name Procedure {Feature} Instrument Type Processing Method Platform CTD Profile Procedure Project ownedBy hostedBy generatedBy

Common Patterns Symbology Catalogue Symbology Catalogue –Stores portrayal rules and symbols for displaying features (objects). –Associates features (e.g. CTD) with symbol(s) which can have scale and other styling dependencies.

Common Patterns Encodings (syntax + semantics) GML - An Open Geospatial Consortium (OGC) Standard. - Tuned for representing geometry and topologies. - Widely adopted to exchange and manipulate data with a spatial component page specification. - Syntax makes no allowance for incorporating other languages, no axioms supported. - All derivatives of this language are called Application Profiles.

Minke <gml:String srsName="EPSG:4326"> 0, , ,60.9 marinemammal CAAB Code WMS maps WFS feature data WCS coverage data Common Patterns Encodings + Protocol OGC (GML-based) web service protocols –Commonly used to encode and send data between systems getCapabilities() describeFeature() getFeature() Supports a few well known service functions including:

CTD GML WFS Encoding {include and import statements for re-using other GML-based ontology elements} {encompasses all deployments and observation members} {properties describing bounding box, time, etc for all deployments} {first observation member} {project, platform, location, time, procedure, composite phenomena properties} {CTD feature} {CTD specific properties encoded in a specialised CSML Profile Feature} {CTD data values} {CTD domain properties and values encoded in a specialised CSML Profile Coverage} {CTD range properties and values encoded in a specialised CSML Profile Coverage} {second observation member – pattern repeats} ……………