GeoRSS

GeoRSS is a specification for encoding location as part of a Web feed. (Web feeds are used to describe feeds ("channels") of content, such as news articles, Audio blogs, video blogs and text blog entries. These web feeds are rendered by programs such as aggregators and web browsers.) The name "GeoRSS" is derived from RSS, the most known Web feed and syndication format.

In GeoRSS, location content consists of geographical points, lines, and polygons of interest and related feature descriptions. GeoRSS feeds are designed to be consumed by geographic software such as map generators. By building these encodings on a common information model, the GeoRSS collaboration is promoting interoperability and "upwards-compatibility" across encodings.

At this point, the GeoRSS collaboration has completed work on two primary encodings that are called GeoRSS Geography Markup Language (GML) and GeoRSS Simple. GeoRSS-Simple is a very lightweight format that supports basic geometries (point, line, box, polygon) and covers the typical use cases when encoding locations. GeoRSS GML is a formal Open Geospatial Consortium (OGC) GML Application Profile, and supports a greater range of features than GeoRSS Simple, notably coordinate reference systems other than WGS84 latitude/longitude. There is also a W3C GeoRSS serialization, which is older and partly deprecated but still the most widely used.

GeoRSS can be used to extend both RSS 1.0 and 2.0, as well as Atom, the IETF's latest standard for feeds.

Examples
Here's a GeoRSS Simple example using Atom. Here is a schema fragment for a GeoRSS GML encoding for RSS 2.0 Here is example of W3C geo GeoRSS