Geodata Discovery

Geodata Discovery Specification - Discovery of Geodata and Geospatial Services

Status

• Version 1.00, 19.4.2010, Stefan Keller -- First release of the specification.

Introduction

The discovery of geodata and geospatial services is crucual of almost every project which involves geoprocessing. General purpose search engines are not capable of recognizing geodata formats and geospatial services. Thus, here is a strong need to support geospatial search services (especially webcrawlers).

Instead a web of documents what is needed, is a web of services.

Specification

The Geodata Discovery standard consists of following parts A and B (both in turn are based standards extensions, called substandards):

• Part A specifies specialized weblinks which provide semantics to help focussed crawlers to find OGC Services, like WMS, WFS, WCS, WPS and/or CSW.
• Part B

Part A. (CONDITIONAL MANDATORY) "See and See also" links containing typified weblinks.

• Weblink typing: xlink Atom link relation type,
• Carrier file formats: HTML (Meta Tags), sitemaps.xml, KML, GeoRSS (xlinks)
• Extension of GetCapabilities from OGC WxS specifications: tbd.!

Part B. (OPTIONAL) Webpages that include a Geotag icon (Microformat). This is for human readability and trustworthiness (Google's principle of visual control) pointing to the "see and see also" links (see above).

CONDITIONAL MANDATORY meand that at least one of the mentioned substandards in A needs to implemented in order to comply to the "Geodata Discovery" standard.

Compliance Test

tbd. Ideally there should be a website which lists conformances tests given a website which was enhanced according to this specifications.

Background

This proposal does not compete with existing standards like CSW. In contrary, it is a supplement of those. It's the basis for better domain-specific search engines, like geocat or geometa.info.

This proposal is based on own experiences and - among others - on the following sources:

• http://highearthorbit.com/geoweb-standards-discoverability/
• http://sgillies.net/blog/985/proposed-standard-for-web-linking

Related standards

• CSW
• OpenSearch-Geo: A leightweight harvesting interface. Its simply some HTML tags: see OpenSearch.org > OpenSearch Geo extension (Draft).

History

• Version 1.00, 19.4.2010, Stefan Keller -- First release of the specification.