R. Suresh (NASA/MTECH)

Ben Burford (JAXA)

Bernhard Buckl (DLR)Contact: - suresh@mayurtech.com

CEOS WGISS Meeting, Beijing , China, September 2004

A RSS based CEOP Metadata Prototype System

Background

RSS Technology

RSS based CEOP Metadata System

Demonstration

Outline

Background

CEOP Metadata discussion and Implementation Plan

Semantic Web Activities for Earth Science

CEOP In situ Data and Metadata

Partners: JAXA, NASA and DLR

Demonstration

What is an RSS?

RSS is a Web content syndication format.

Its name is an acronym for Really Simple Syndication.

RSS is a mechanism for metadata/data providers to let users know what new content is available

RSS RSS is a dialect of XML. All RSS files must conform to the XML 1.0 specification as published on the World Wide Web Consortium (W3C) website. The RSS has multiple versions. Current version is 2.0.

RSS feeds include site tracking by search engines and other software.

Receive customized information from various sources.

RSS feed is machine-readable

Continuous real time update of information

RSS feed applications

RSS Applications

• Oceanographer can select only ocean related metadata to be delivered to his desktop.• A person interested in Disaster data can get only metadata related to disaster data.• A user interested in weather monitoring can receive customized US weather data.

Other Applications

• News• Sports • Entertainment• Job Listings• Document cataloging

RSS Feeders and Readers

Creation of RSS based system is simple. It involves two steps

1. Generation of RSS feeds: Metadata/data providers can describe metadata using RSS format

Metadata can be aggregated for different disciplines : Ocean, Atmosphere, and Solid Earth or locations of stations in case of In situ metadata

2. Users can download RSS readers and install on their system

These readers check various sites for RSS feeds and updates information. Users can set up the frequency of update and select the data they want.

At the top level, a RSS document is a <rss> element, with a mandatory attribute called version, that specifies the version of RSS that the document conforms to. If it conforms to this specification, the version attribute must be 2.0.

Subordinate to the <rss> element is a single <channel> element, which contains information about the channel (metadata) and its contents.

RSS Feed Description

Identify required and optional sub-elements of <channel>

Required channel elements:

Title: The name of the channel. It's how people refer to your service. If you have an HTML website that contains the same information as your RSS file, the title of your channel should be the same as the title of your website.

Link: The URL to the HTML website corresponding to the channel.

Description: Phrase or sentence describing the channel.

Item:

A channel may contain any number of <item>s

RSS Feed Description

Optional channel elements:

language: The language the channel is written in.

pubDate: The publication date for the content in the channel.

lastBuildDate: The last time the content of the channel changed.

ttl: ttl stands for time to live. It's a number of minutes that indicates how long a channel can be cached before refreshing from the source.Image Specifies a GIF, JPEG or PNG image that can be displayed with the channel.

and …

RSS Feed Description

Elements Description

Title The title of the item.Link The URL of the item.Description The item synopsis.

Author Email address of the AuthorPubDate Indicates when the item was published.Source The RSS channel that the item came from

RSS Feed Description-Item

<item> <title>Earth Invaded</title> <link>http://news.example.com/2004/12/17/invasion</link> <description>The earth was attacked by an invasion fleet from halfway across the galaxy; luckily, a fatal miscalculation of scale resulted in the entire armada being eaten by a small dog.</description> </item>

Additionally, the feed itself can have metadata associated with it, so that it can be given a title (e.g., "Bob's news headlines"), description, and other fields like publisher and copyright terms.

RSS Feed example

CEOP RSS Implementation plan

• Creating an RSS feed for In situ metadata/data

• Create, reuse or Modify RSS reader

• Create Distributed sites

Place RSS feed examples on distributed servers (JAXA, DLR, NASA)

Users can install RSS readers which will assist them in obtaining real time updates for metadata/data

RSS feeds for CEOP applications

NASA Feed DLR Feed JAXA Feed

Earth Science Gateway Portal

User RSSReader

User RSSReader

User RSSReader

CEOP Metadata System Architecture

Automatic update of metadata• Aggregation of metadata parameters

Show me all sites which have data for this time period?Specify update intervals i.e., once a day, hourly, …

Provides links to sources of data• No processing of data currently • Simply display mechanism for updates

Give me the maximum temperature for this site for the last month.

CEOP In Situ Metadata Implementation FEATURES

RSS Feeder Tools

Tools for generating RSS Feeds

www.webreference.com/cgi-bin/perl/makerss.pl

thelocust.org/projects/instantrss//

Feed Validator

http://feedvalidator.org

RSS Readers 

RSS readers Reference sites

AWASU www.awasu.com

BLOGLINES www.bloglines.com

My Yahoo

My.yahoo.com

Radio Userland Radiouserland.com

WinRSS www.brindys.com/winrss

Pluck www.pluck.com