Web Archives and Queries

The second aspect of this project will be constructing a web service that will be able to query and search the data set, and making this available through VO services. This will build on the work done by Albert Teoh in constructing the web archive, and extending this to provide VO Cone Search queries that return VOTables.

Some links:

• Albert's web archive: (I did have the link here, but it's an internal page so I don't know if we want to publicise it on the wiki. It's denoted here as <ARCHIVE_BASE> -- contact me if you don't know the address).
• My working page that incorporates the limited S70 data (from $S70V directory): <ARCHIVE_BASE>/test/whi550/
  • This just does cone-searching on the S70 data.
  • A temporary table is loaded each time a query is made -- this is just for testing purposes, but is enough to get the idea.
• A cone-search web service that returns a VOTable is available at <ARCHIVE_BASE>/test/whi550/conequery-vo.php This accepts three parameters (as per the VO conesearch standard): RA, DEC, SR. It is available to test now: try something like <ARCHIVE_BASE>/test/whi550/conequery-vo.php?RA=0.&DEC=-49.&SR=1. and you should see the result in your web browser. To save to a file (which you could then load into a VOTable browser such as TOPCAT: ​http://www.starlink.ac.uk/topcat/), try

  wget -O output_file <ARCHIVE_BASE>/test/whi550/conequery-vo.php\?RA=0.\&DEC=-49.\&SR=1.
  

Registering a VO service

Once we have a VO Cone Search service up and running, we will want to register it so that people can see it. This is a reasonably straight-forward procedure as it is basically providing a set of metadata about the service to a registry. Some registries can be found at:

• NVO: see Section 3.1 on ​http://www.us-vo.org/pubs/files/PublishHowTo.html for links
• Euro-VO : see ​http://www.euro-vo.org/pub/tc/registries.html for links

It is unclear whether it is sufficient to register at just one registry, or whether they are still independent (the aim is for one registration to be sufficient, but are we at that point yet?). This needs to be followed up.

The full list of metadata that can be provided to describe a service is detailed in the IVOA document on Resource Metadata: ​http://www.ivoa.net/Documents/latest/RM.html Most of the registration pages are forms where specific fields are filled in, often depending on the type of service being registered.