ISO 19110:2005 Geographic information - Methodology for feature cataloguing

From ICA Wiki
Jump to navigation Jump to search


Full name ISO 19110:2005, Geographic information – Methodology for feature cataloguing
Version Edition 1
Amendments ISO 19110:2005/Amd 1:2011
Corrigenda None
Published by ISO/TC 211
Languages English, French
Online overview
Type of standard ISO International Standard
Meta and application level
Related standard(s) ISO/TS 19103:2015, Geographic information – Conceptual schema language
ISO 19109:2015, Geographic information – Rules for application schema
ISO 19115:2003, Geographic information – Metadata
ISO 19117:2012, Geographic information – Portrayal
ISO 19126:2009, Geographic information – Feature concept dictionaries and registries
ISO 19135:2005, Geographic information — Procedures for item registration
ISO/TS 19139:2007, Geographic information — Metadata — XML schema implementation
Application This standard does not define a feature catalogue (or feature classification system, as many would understand it), but specifies the methodology for cataloguing feature types (or feature classes, as many would understand it) to compile a feature catalogue. However, it does not specify how to decide what the feature types should be (their collection criteria).
Conformance classes None specified
Implementation benefits ENC software validates that data are conformant with the IHO S-57 ENC product specification. Conformance violations are labelled as either an error or as a warning. This is important to ensure that the correct ENC is produced and that the software is implemented according to the same standard.
Products Catalogue with single-use feature attributes
Catalogue with single-use feature attributes and association roles
Catalogue with single-use feature attributes, association roles and operations
Catalogue with multiple-use feature attributes, associations and operations
Catalogue with single-use feature attributes and inheritance
Catalogue with single-use feature attributes and association roles with inheritance
Catalogue with single-use feature attributes, association roles and operations with inheritance


ISO 19110:2005 defines the methodology for cataloguing feature types. This International Standard specifies how feature types can be organised into a feature catalogue and presented to the users of a set of geographic data. ISO 19110:2005 is applicable to creating catalogues of feature types in previously uncatalogued domains and to revising existing feature catalogues to comply with standard practice. ISO 19110:2005 applies to the cataloguing of feature types that are represented in digital form. Its principles can be extended to the cataloguing of other forms of geographic data. Feature catalogues are independent of feature concept dictionaries defined in ISO 19126 and can be specified without having to use or create a feature concept dictionary.

ISO 19110:2005 is applicable to the definition of geographic features at the type level. ISO 19110:2005 is not applicable to the representation of individual instances of each type. ISO 19110:2005 excludes portrayal schemas as specified in ISO 19117.

ISO 19110:2005 can be used as a basis for defining the universe of discourse being modelled in a particular application, or to standardize general aspects of real world features being modelled in more than one application.

Implementation benefits

ISO 19110:2005 provides a rigorous methodology for cataloguing feature types (feature classes) to compile a feature catalogue (also known as a classification system) and for publishing the catalogue in a registry (a formal online repository). Closely related to ISO 19110:2005 is ISO 19126:2009, Geographic information – Feature concept dictionaries and registries (see 11.3.2), which specifies how to set up a concept dictionary of the abstract feature concepts that can be specified in detail in creating a feature catalogue. However, ISO 19110:2005 does not actually define a feature catalogue and it does not specify how to decide what the feature types should be (their collection criteria), which is actually a poorly understood problem.

Implementation guidelines

ISO 19110:2005 and ISO 19126:2009 probably have a more sophisticated approach to classifying features in a geospatial dataset than most users are accustomed to, which probably makes them a bit challenging. The amendment to ISO 19110:2005 was published in 2011 and makes significant changes to the standard – the amendment is almost as long as the original standard itself. It also makes it more difficult to understand the standard, unfortunately, as the amendment is published separately and not merged into the original standard. Further, the amendment uses UML classes from ISO/TS 19139:2007, Geographic information – Metadata – XML schema implementation, without expanding them in the tables, so it can appear that some things were deleted by the amendment, when they were not. The main changes introduced by the amendment are to improve harmonization with other ISO/TC 211 standards, cater for XML, facilitate using ISO 19110:2005 to create geographic feature catalogues, ensure consistent descriptions of the feature types of an application schema, and enable registering feature catalogues and their feature types. This discussion is of ISO 19110:2005 as amended in 2011.

ISO 19110:2005 is also currently being revised and as it received 100% support in February 2014 in the DIS ballot, it is likely that the revised standard will be published before the end of 2014.

A feature occurs on two levels, as an instance, which is the actual thing in the real or imaginary world being modelled (a discrete phenomenon associated with its geographic and temporal coordinates that may be portrayed by a particular graphic symbol), or as a type, which is a grouping of instances into a class with common characteristics. Recognising and selecting the relevant characteristics (and hence the classification itself) is subjective and depends upon the needs of particular applications.

Clause 5.2 describes the XML namespaces used in this standard, namely gco, gfc, gmd and gmx. Clause 6 of ISO 19110:2005 provides an overview of the general requirements for a feature catalogue: the form of names and definitions; the requirements for feature types, feature attributes and feature attribute values; and the requirements for the complex relationships between feature types, namely:

  • Feature operation: an action or query that can be performed on a feature, such as upgrading or downgrading an attribute (e.g. the category for an Important Bird Area), or checking the water level at a weir. A feature operation may have attributes that trigger it, that provide inputs for it or that are affected by it.
  • Feature association: a relationship linking one feature to another, such as between a river and its catchment, or between a bridge and what it carries and what it spans.
  • Association roles: the function or undertaking of each feature type or instance in the association. An association role can be navigable, meaning that it can be used to find the target feature from the source feature. An association role can also be bound to a particular feature type.

Annex B provides the feature catalogue template, which has tables similar to the data dictionary in ISO 19115:2003, Geographic information – Metadata (see 11.2.2), and UML diagrams.

Essentially, each feature catalogue is required to have a name, scope, version number, version date, producer and a set of feature types. It may have an identifier, language, character set, locale, described field of application and a set of definition sources (unfortunately, not linked to the definitions taken from each of them), inheritance relationships, global properties, and if its feature types have feature operations, it may have a functional language for defining them.

A feature type then has a name, a definition, links to the feature catalogues that contain it, and an indicator of whether or not it is abstract (i.e. a superclass with no instances in practice). It may also have a code, aliases, superclasses (from which it inherits operations, associations and properties), subclasses (which inherit operations, associations and properties from it), properties, constraints, and a definition reference. Note that a class (feature type) may have more than one parent, meaning that a feature catalogue is not restricted to a pure hierarchy, but could also be a partially ordered set (poset).

Annex C provides feature cataloguing examples and Annex D provides more detailed descriptions of the feature cataloguing concepts, namely feature operations, feature attributes, feature relationships (particularly generalization and aggregation), and synonyms and included terms (aliases or alternative names), and also provides some examples. The amendment adds two normative annexes, Annex E, which provides the XML encoding description, and Annex F which specifies the management of feature catalogue registers. The amendment also adds Annex G, which contains XML implementation examples.