3MAP - milestone 3.

metadata : standards

Rationale

Interoperability with spatial data providers will be crucial in broadening the scope of our dataset. The emergence of international standards for geospatial metadata facilitates this goal.

Relevant specifications

Key OpenGIS Consportium specifications (with ISO/TC 211 designations and links in brackets):

OGC Feature Geometry
(ISO 19107:2003 - Spatial Schema)

Specifies conceptual schemas for describing the spatial characteristics of geographic features, and a set of spatial operations consistent with these schemas. It treats vector geometry and topology up to three dimensions. It defines standard spatial operations for use in access, query, management, processing, and data exchange of geographic information for spatial (geometric and topological) objects of up to three topological dimensions embedded in coordinate spaces of up to three axes.

OGC Metadata
(ISO 19115:2003 - Metadata)

Defines the schema required for describing geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal schema, spatial reference, and distribution of digital geographic data.

Review of relevant metadata standards

The baseline for discovery metadata is the Dublin Core.

The first comprehensive geospatial metadata specification was the Content Standard for Digital Geospatial Metadata (CSDGM) from the US Federal Geographic Data Committee.
The CSDGM spec is SGML based, and contains 334 tags.

The most useful geospatial standards body is the OpenGIS Consortium (OGC), which works closely with ISO/TC211 (International Standards Organisation Technical Committee 211 on Geographic information/Geomatics).

Many organisations are converging on the use of the OpenGIS standards. For example, CEN (the European Committee for Standardisation) TC 287 unanimously resolved to adopt the ISO/TC 211 standards as European standards at the end of 1998.

ANZLIC (the joint Australia/New Zealand government Spatial Information Council) has been working with ISO/TC 211 on ISO 19115, and the ANZLIC Metadata Guidelines are designed to comply with that standard.

The ISO/OGC geospatial standards can be applied in various encodings; one application is GML3, the Geospatial Markup Language.

3map will use OGC standards wherever possible.

The OGC Abstract Specification includes:

Topic 0 - Overview
Topic 1 - Feature Geometry
Topic 2 - Spatial Reference Systems
Topic 3 - Locational Geometry
Topic 4 - Stored Functions and Interpolation
Topic 5 - The OpenGIS® Feature
Topic 6 - The Coverage Type
Topic 7 - Earth Imagery
Topic 8 - Relations Between Features
Topic 9 - Accuracy
Topic 10 - Feature Collections
Topic 11 - Metadata
Topic 12 - The OpenGIS® Service Architecture
Topic 13 - Catalog Services
Topic 14 - Semantics and Information Communities
Topic 15 - Image Exploitation Services
Topic 16 - Image Coordinate Transformation Services

Topics 1 and 11 are particularly relevant, and are linked and described in the lefthand column of this page.

The OGC Implementation Specifications include:

Simple Features Specifications for OLE/COM, CORBA 1.0, and SQL 1.1 (as well as other implementation specs).

The SFS Spec for SQL is particularly relevant - see Implementation Notes.