Description

The Data Federation Tool (DFT) is capable of taking a set of VOTables generated by a single-target cone-search sent to a number of services, present the user with options on how to merge the results in a graphical user interface. The final product is, in principle, another VOTable.

Flow description

• The VOTables to be merged provide all the metadata it is needed to pre-federate the results, that is, to suggest the user what's likely to represent mergeable columns and any possible problems the data may contain.

• DFT should be invoked by another process (the ADW or the portal) and keep track of any user-specific ID.

• The VOtables should be broght to the machine where the DFT runs, possibly converted to internal format to facilitate their ingestion several times (during the many trials a user may make before a final table is generated).

• During the first ingestion of the tables DFT must make sure that all tables belong to the same target, that they are the product of a cone-search, and that coordinates for J2000 are present.

• After validation, a plot should be generated representing the positions of the sources respect to the target (X = delta(RA), Y = delta(Dec) ), with different symbols for the different catalogues. In the case a catalogue contains a source observed many times, a grayscale graph (2D histogram) is highly desireable.

• The plots should be part of the first page generated by the DFT, so the user can have a clear idea of what the results of the search are before taking any steps towards the table analysis.

• (simultaneously with the plot generation) the tables' meta-data will be analyzed in order to present the user with different options to merge the information, in particular, cases when a UCD represents more than a column in one of the catalogues or when columns are represented in non-equivalent coordinates.

  A more complete list of options will be listed in another section of this document.

• The options presented to the user will allow him/her to produce a table which should reflect his/her needs, including the format in which this final product will be written.

• The options chosen by the user to analyze these tables will be stored in MySpace in order to accumulate knowledge. A user may recall previous settings to be applied to tables coming from catalogues having a similar content.

Interaction with other components

DMF is one of the components in AstroGrid I04, and should directly interact with the ADW and mySpace.

Interaction with ADW

DMF will be invoked by ADW.

The following pieces of information should be received by DMF:

• user related information (certificate, UID, etc) in order to access information on behalf of the user in mySpace.

• URLs of the tables to be downloaded from mySpace.

Interaction with mySpace

DMF will capture the data-files in the form of VOTables from mySpace, acting on behalf of the user. The following aspects of the interaction are foreseen:

• Open a protected session with mySpace.

• Recover the VOTables stored in the indicated URLs

• Recover my.DMF.history from mySpace, where my.DMF.history acts as a holder of previous user's operations.

• Once the user decides to produce a final table, the parameters of such operation are stored in the local copy of my.DMF.history, this copy is then uploaded to mySpace. Perhaps some kind of lock mechanism will be needed to ensure that no information is added at the same time.

• If the user chooses, the final table will be stored in mySpace.

-- PatricioOrtiz - 21 Oct 2003