-- SimonKrughoff - 15 Nov 2004

SExtractor Web Service with Cross Matching

Team:	Simon, Andy, Roy
Testing:	Simon, Andy, Roy, Andrew Hopkins, Sam Schmidt
Doc:	Simon
Mirror:	PITT http://frank.phyast.pitt.edu:8080/wsext (under construction)

WSExtractor takes an upload image and runs SExtractor with a set of default parameters. The user can choose output fields. The resultant catalog is uploaded to OpenSkyQuery via the webservice interface and runs an xmatch query on the temporary table with a catalog of the users choice. The user may also select the output fields in the returned crossmatched catalog. The web service interface allows modification of the ADQL query string, the output fields, and the input parameters to SExtractor.

Web Service Interface

The web service interface currently only works with clients written in java under the Apache Axis framework. This is due mostly to an Axis specific datatype (DataHandler? ) which is used to make handling of SOAP attachments more user friendly.

An additional limitation inherent in SExtractor is the inability to handle image files with bad, incorrect, or improperly formatted WCS solutions.

Web Front End

The web front end to WSExtractor is implemented in JSP with Apache Struts. The page allows a user to upload a file to the server and choose a database to crossmatch the extracted catalog with. The user may also define the output fields from SExtractor and the crossmatched catalog. The parameter list for the chosen crossmatch catalog are gotten dynamically by calls to SkyPortal? . Currently, the service uses a default set of input parameters. This must be changed to allow modification of the input parameters through an "advanced" interface.

Once the extracted catalog with crossmatched data has been constructed, the user may plot the VOTable using and imbedded voplot applet (thanks to Wil). The user may also ship the source catalog, crossmatched catalog, and image off to an embedded version of Aladin hosted at Harvard. Image and votables are unique to each session, however, upon returning to the service homepage the session is reset.

At some point, we need a better name for the service. So far, the suggestions are: Objectotron 5000, WSExtractor, and Image Gobbler.

General Discussion

06 Dec. 2004 We still need to come up with a better name for the web interface. I the machinery is working well, I think. As long as one doesn't try too hard, it seems to be robust. There are a few issues which should be delt with before this becomes a fully deployed tool.

1.	We need to finalize and freeze the interface.
2.	Come up with science applications
	Calibrate an optical image against SDSS
	Compare IR image with sdss dropouts and FIRST data
3.	When images are too large, they do not upload properly

|4.|If detection threshold is too low, the source catalog is not uploaded to OSQ because of timeout (either query or server)|

5.	Documentation: 1 page advert, cheat sheet

Tasks for WSExtractor for Dec 1

General/Programming

Rename service to something catchier	NVO meeting
Some sort of tester for images with SExtractor
Embed Aladin running locally to cut down on image transfer times
Allow users to specify a URL for image access
Modify WSDL to remove dependence on DataHandler? datatype
Improve sessions handling to accept multiple concurrent calls

Completed tasks

Expert page for web interface	Dec. 15	Done
Improve error check to catch things like zero length VOTables	Jan. 1	Done (Sort of)
Both web service and web interface take images for upload
Run SExtractor on uploaded image
Upload catalog to OpenSkyQuery
Send ADQL query to OpenSkyQuery and return VOTable with results
Build web interface which allows plotting and source position overlay

Documentation

Relatively little has been done, but having the summerschool.zip file has helped
Full example of use with web service
Description of interaction between WSextractor and OpenSkyQuery
Links to helpful VOTable tools and description of SExtractor