VOTool: A VOTable Visualization and Editing Tool

VOTool: A VOTable Visualization and Editing Tool

Description

VOTool is a prototype application being developed as part of the "legacy systems" NVO work being at NOAO. It is meant to provide a simple interface for users to view and interact with VOTable documents in a form which is more comfortable than either dealing with the XML directly or using static translators.

The task was developed as an IRAF GUI using an XML parser built from scratch in the IRAF environment. Parts of the code used in this application will become the basis for an external package and system interfaces that will allow IRAF to handle VOTables as standard data objects the way images are commonly used now. Tasks for converting VOTables to/from other forms of tables used in the system now, as well as more sophisticated tools for editing VOTables (e.g. merging, selection, pretty-printing, etc) and interactively querying NVO services are planned.

VOTool is still rapidly evolving but is fully functional as a VOTable browser. Editing of tables is currently limited to only table row selection, column sorting, and changes to individual cells however there are plans to allow for adding new columns to tables (e.g. add a column of B-R colors using an expression based on the 'B' and 'R' magnitude columns) and merging/insertion/deletion of entire RESOURCE elements in the near future. A preliminary plot capability also exists allowing users to graph one column of a table against another (also with a limited expression syntax). Since VOTables can often contain URLs or other data streams, a function to download such data on demand will also be implemented. Image data (contained either directly in the document or as a URL in a table) can be displayed to common display tools such as XImtool or DS9.

A more complete feature and to-do list will be given here after the initial release.

Screenshots

Sample screenshots of the VOTool current release. Click on the thumbnail to see a larger image.

Startup splash screen. The control panel on the lower left allows the user to load and save files, move through lists of VOtables and edit the file.

Metadata summary screen. The document summary is at the top with a scrollable box below it containing links to individual RESOURCE and TABLE elements within the document. In this case, a VOTable containing multiple RESOURCES is shown, each RESOURCE contains a description and link to the table data.

Resource Metadata viewer. Each RESOURCE element will contain various descriptive elements including global properties of the table (PARAM elements) and the table column descriptions (FIELD tags), along with a description of the resource itself. The display will vary depending on the document structure, i.e. if there are no PARAM elements the associated table will not be displayed.

Table data viewer. This is a scrollable table showing the complete TABLEDATA element of the RESOURCE. Columns in a table may be sorted in ascending or descending order with a mouse click on the column header, the column description is updated on the bottom of the screen as the user moves through the table. Cells with a blue foreground (not shown here) represent elements which are either explicitly a URL to some resource (e.g. in a Simple Image Access result) or are entity substitutions from the FIELD element. Selecting the cell will download the link and display the result (e.g. in an HTML window or in the case of an image by displaying the FITS file to an XImtool/DS9 viewer).
The table show here has had a number of rows selected using an expression typed in at the bottom of the panel. Once selected, rows may be deleted from the table and the results saved to a new file. Selection expressions may use either the column name or UCD as an operand in any combination (e.g "(b_mag - r_mag) > 3.0" in the case where a B-R color column is not provided.

Table plotting window. Table columns which are determined to be numbers may be plotted to show e.g. the RA/DEC distribution of the table elements. A crude expression operator is provided to plot e.g. the difference of two columns as shown here. A box may be dragged around points in the table to select to corresponding rows in the table.

The raw XML viewer window. This provides a look at the VOTable as it's read by the task. The XML text is fully searchable and VOTable 'keywords' are highlighted in bold.

Download

A very early test release of VOTool is available from, or questions/comments can be directed to, the author at fitz@noao.edu.

A direct link to the distribution will be made available on this page once it is ready.

Requirements:

Users should understand that not all features are currently working and there are a number of known bugs yet to be resolved. The task currently requires that you have IRAF installed on your system however we hope to remove that dependency in the final distribution. VOTool is essentially an X application and as such will not work under MS Windows environments except when using an X emulator while connected to a supported system. Supported platforms include all currently supported IRAF systems: SunOS/Solaris, Linux, FreeBSD, Mac OSX, HP/UX, Alpha Tru64, and SGI IRIX.

IRAF NOAO NVO

Author: Mike Fitzpatrick, NOAO

	Startup splash screen. The control panel on the lower left allows the user to load and save files, move through lists of VOtables and edit the file.
	Metadata summary screen. The document summary is at the top with a scrollable box below it containing links to individual RESOURCE and TABLE elements within the document. In this case, a VOTable containing multiple RESOURCES is shown, each RESOURCE contains a description and link to the table data.
	Resource Metadata viewer. Each RESOURCE element will contain various descriptive elements including global properties of the table (PARAM elements) and the table column descriptions (FIELD tags), along with a description of the resource itself. The display will vary depending on the document structure, i.e. if there are no PARAM elements the associated table will not be displayed.
	Table data viewer. This is a scrollable table showing the complete TABLEDATA element of the RESOURCE. Columns in a table may be sorted in ascending or descending order with a mouse click on the column header, the column description is updated on the bottom of the screen as the user moves through the table. Cells with a blue foreground (not shown here) represent elements which are either explicitly a URL to some resource (e.g. in a Simple Image Access result) or are entity substitutions from the FIELD element. Selecting the cell will download the link and display the result (e.g. in an HTML window or in the case of an image by displaying the FITS file to an XImtool/DS9 viewer). The table show here has had a number of rows selected using an expression typed in at the bottom of the panel. Once selected, rows may be deleted from the table and the results saved to a new file. Selection expressions may use either the column name or UCD as an operand in any combination (e.g "(b_mag - r_mag) > 3.0" in the case where a B-R color column is not provided.
	Table plotting window. Table columns which are determined to be numbers may be plotted to show e.g. the RA/DEC distribution of the table elements. A crude expression operator is provided to plot e.g. the difference of two columns as shown here. A box may be dragged around points in the table to select to corresponding rows in the table.
	The raw XML viewer window. This provides a look at the VOTable as it's read by the task. The XML text is fully searchable and VOTable 'keywords' are highlighted in bold.