Using VOExplorer

VOExplorer is used to search for resources in the Virtual Observatory; it does this by querying the AstroGrid Registry which is a service which stores (and regularly updates) the details of all of these resources.

VOExplorer has four panes:

1. The Smart and Static Lists pane (top left) displays the names of resource lists which have been used to query the AstroGrid registry.

2. The Resource Lists pane (top right) lists the resources.

3. The Information, Table Metadata and XML pane (bottom right) displays information on any resource selected in the Resource Lists pane.

4. The Actions and About pane (bottom left) lists the actions that can be invoked on the selected resources (clicking an action invokes it).

A typical session with VOExplorer might involve the four panes in the order listed: create a list of resources using the Smart and Static Lists pane, select a resource in the Resource Lists pane, read a description of the resource in the Information, Table Metadata and XML pane and invoke an action on the resource using the Actions and About pane.

Follow this guide to find out how to use VOExplorer.

Smart and Static Lists Pane

Virtual Observatory resources are discovered with VOExplorer by creating resource lists; these resource lists are listed in the Smart and Static Lists pane. There are two kinds of lists:

• a static list of resources (preceded by in the pane) which the user can manually add items to

• a smart dynamic list of resources (preceded by in the pane) which is defined by a query to the AstroGrid Registry.

Some example smart and static lists are provided with VOExplorer; double-click "Examples" to view these lists (if only "Resource Lists" is visible, double-click it to reveal the "Examples" folder) and click each list in turn to display the resources in Resource Lists pane.

Creating a Smart List

New smart lists are created by clicking the New Smart List button, selecting File->New Smart List on the menu-bar or using the keyboard shortcut Command-N (Mac OS X) or Ctrl-N (Windows and Linux); the Resource List and Information and Table Metadata panes are replaced by a single pane used to define the name and search criteria of the smart list (see the example below). A name should be entered for the list and search criteria can be defined using the drop-down list list and the text box. Additional criteria can be added by clicking the green "+" button and they can be removed by clicking the red "-" button. Click the "Create" button once the search criteria have been defined.

Example: In the screenshot shown above, a new smart list has been defined to search for Sloan Digitized Sky Survey (SDSS) Data Release 5 (DR5) resources in the Virtual Observatory; the unique name "SDSS-DR5" has been given to this Smart List. Two search criteria have been defined for this Smart List:

• Any main field should contain "SDSS".

• Any main field should contain the text "DR5".

In this example VOExplorer is configured to match "all of the following conditions" although it can be configured "any any of the following conditions" using the drop-down list.

Creating a Static List

New static lists are created by selecting File->New Static List on the menu-bar or using the keyboard shortcut Command-Shift-N (Mac OS X) or Ctrl-Shift-N (Windows and Linux); the Resource List and Information and Table Metadata panes are replaced by a single pane for adding resources. To add a resource, click the green "+" and in the text box that appears, enter the IVORN (International Virtual Observatory Resource Name) of the resource you wish to add to the list; each text box should contain one IVORN.

Example: In the screenshot shown above, a new static list has been created containing two VO Resources:

1. The INT Photometric HAlpha Survey (IPHAS) catalogue which has an IVORN of ivo://uk.ac.cam.ast/iphas-dsa-catalog/ceaApplication

2. The Sloan Digital Sky Survey Data Release 5 (SDSS-DR5) catalogue which has an IVORN of ivo://wfau.roe.ac.uk/sdssdr5-dsa/ceaApplication

Renaming a List

To rename a list, select it (single click) in the Smart and Static Lists pane and then do one of the following:

• Right-click it and then left-click "Rename" from the menu that appears.

• Click File->Rename from the menu-bar.

Edit the name of the list in the dialog box that appears and click "OK".

Editing a List

To edit a list, select it (single click) in the Smart and Static Lists pane and then do one of the following:

• Right-click it and then left-click "Edit" from the menu that appears.

• Click File->Edit from the menu-bar.

• Use the keyboard shortcut Command-E (Mac OS X) or Ctrl-E (Windows and Linux).

The Resource List and Information and Table Metadata panes are once again replaced by the pane used to define the search criteria and thus the search criteria and the Smart Lists' name made be modified.

Duplicating a List

To duplicate a list, select it (single click) in the Smart and Static Lists pane and then do one of the following:

• Right-click it and then left-click "Duplicate" from the menu that appears.

• Click File->Duplicate from the menu-bar.

• Use the keyboard shortcut Command-D (Mac OS X) or Ctrl-D (Windows and Linux).

A duplicate of the Smart List will appear in the Smart and Static Lists pane with "Copy of" appended to the beginning of the original Smart Lists' name.

Deleting a List

To delete a list, select it (single click) in the Smart and Static Lists pane and then do one of the following:

• Right-click it and then left-click "Delete" from the menu that appears.

• Click File->Delete from the menu-bar.

• Use the keyboard shortcut Command-Backspace (Mac OS X) or Ctrl-Backspace (Windows and Linux).

Grouping Lists - Creating Folders

Lists may be grouped together in folders. New folders are created by either selecting File->New Folder from the menu-bar or right-clicking within the Smart and Static Lists pane and selecting New->New Folder. Enter a name for the folder in the dialog box that appears and click "OK"; the folder will appear in the Smart and Static Lists pane. Lists may be added to the folder by drag-and-dropping them on to the folder name or icon. Folders may be deleted in the same way as lists.

Exporting Lists or Folders of Lists

Lists or folders of lists may be exported from VOExplorer. To export a list or folder of lists, select it in the Smart and Static Lists pane and then either select File->Export from the menu-bar or right-click in the Smart and Static Lists pane and click "Export" in the menu that appears. Use the file browser that appears to enter a file name for the exported file and to save to a suitable location.

Importing Lists or Folders of Lists

Lists or folders of lists that have been exported from VOExplorer can be re-imported using the following method. Either select File->Import from the menu-bar or right-click in the method may be very easily re-imported. Either select File->Import from the menu-bar or right-click in the Smart and Static Lists pane and click "Import" from the menu that appears, a file browser will appear which should be used to select the file containing the lists or folder of lists. Click "OK" to import the lists, they will appear in the in the Smart and Static Lists pane.

Resources List Pane

Click a list name in the Smart and Static Lists pane will display the resources in a table in the Resources List pane. Each column displays a different piece of information about the resources and extra columns of information may be added. The resources may be sorted by any column and tools are provided to filter the results further. Information about selected resources and methods to invoke actions upon them are provided in the Information and Metadata and Actions and About panes, respectively.

Selecting Resources

Single resources may be selected by clicking once on their row. A range of resources may be selected by clicking on the first row in the range, holding down the shift key, and selecting the last row; the two selected resources and the resources in-between will now be selected. Non-consecutive resources can be selected by clicking on the first resource and then clicking on any subsequent resource while holding down the Command- key (Mac OS X) or the Ctrl- key (Windows and Linux).

The Default Columns

By default VOExplorer displays the following information about the listed resources:

• Status: This column lists the current status of the resources; means that the resource is up and working, means that the resource is down and means that the service is unknown to the monitoring service. Note that there are occasional delays in retrieving resources statuses from the monitoring service resulting in inaccurate statuses being displayed.

• Flag: Individual resources may be "flagged" (with ) so that they are easier to locate in the resource lists. Resources are flagged using the Information and Table Metadata pane.

• Title: Displays the titles of the resources.

• Capability: Displays the types of services provided by the resources; each icon represents a different type of service (see Summary of VO Resource Capabilities for a description of each service and the corresponding icon).

• Date: The date that the VO Resource was last updated.

Adding and Removing Columns

Clicking the button in the top right-hand corner of the resources list displays a menu to add or remove columns; tick or untick a column to make it appear or disappear from the table. All columns can be shown in the table by clicking "Show All", while clicking "Show Defaults" returns the table to showing the default columns.

Each column provides another piece of information about the resources that are listed; most of this information is retrieved from the resources' metadata. Read the Summary of VO Resource Columns to find out what each column provides.

Sorting the VO Resources

By default, VO Resources are listed in the order that they are retrieved from the Registry (the AstroGrid service which provides the list of VO Resources). One may sort the list in ascending or descending order of any displayed column by clicking on the column name. Clicking once will display next to the column name and the resources will be sorted in ascending order with respect to that column. Clicking once more displays next to the column name and the resources will be displayed in descending order.

Quick Filtering of the VO Resources List

The filter text box ( in the upper right hand corner of the Resources List pane can be used to quickly filter the entries in the resources list. Click in the text box and type the text that you wish to filter by; VOExplorer will search the meta-data of all the displayed resources and those that do not contain matching text are hidden from view.

To view all of the resources again, delete the text from the filter text box or click in the corner of the filter text box which automatically remove the text.

Advanced Filtering of the VO Resources List

Click to reveal the advanced filtering controls (see the image above). These controls can be used to filter the resources using up to three pieces of information contained in the resources meta-data; the type of information used to filter the resources can be changed from the defaults using the drop-down lists. The text-based quick filtering can be used in conjunction with this advanced filtering.

Example In the above screenshot, only resources supplying data in the optical waveband are displayed; the filtering was invoked by clicking "optical" in the list under "Coverage - Waveband".

Click to hide the advanced filtering tools and display all of the resources.

Information, Table Metadata and XML Pane

The Information, Table Metadata and XML pane provides information on the resource that has been selected in the Resources List pane. There are three tabs in this pane, an "Information tab" which is displayed by default, a "Table metadata tab" and an "XML tab". To switch between the tabs click either "Information", "Table Metadata" or "XML" at the top of the Information, Table Metadata and XML pane.

The Information Tab

This tab provides information (such as a description and the service type) about the resource that has been selected in the Resources List pane; this information is retrieved from the resources' meta-data. The "Annotate" panel at the right-hand side of the information tab can be used by the user to:

• Flag a resource making it easier to find the resource list.

• Highlight a resource by changing the colour of its title as it appears in the resource list.

• Give the resource an alternative title.

• Add some notes about a resource.

• Add some word tags to a resource.

These annotations are stored on the local computer and will appear in the "Information" tab whenever an annotated resource is displayed. The AstroGrid science team may additionally annotate resources to aid astronomers using them and these annotations will automatically be retrieved if they exist.

The Table Metadata Tab

For VO Resources providing Table Metadata (represented by in the "Capabilities" column) the Table Metadata tab will display the names, description, datatype, UCD (Uniform Content Descriptor) and the Units of columns in the tables provided by the resource. Use the "Table" drop-down list to view details about the columns in other tables provided by the resource. Use the "Catalogue" drop-down list to view other catalogues provided by the resource.

The XML Tab

All virtual observatory information is stored in XML or Extensible Markup Language. This information is translated to a more digestable format on the "Information tab" and the "Table Metadata" tabs but if one wishes to view the source XML of the selected resource, click the "XML tab".

Actions and About Pane

The Actions and About pane is split into two sections, the "Actions Panel" and the "About Panel". Both panels may be "collapsed" by pressing and expanded again by pressing .

The Actions Panel

The actions panel displays a list of (clickable) actions that can be invoked on the current selected resources. Typical resources and the actions that may be invoked on them are:

• Cone Search/SIAP/SSAP: Query - will launch the Astroscope for the user to perform a position search against the selected resource or resources (if multiple Cone Search/SIAP/SSAP resources have been selected).

• STAP: Query - will launch the HelioScope/AstroScope interface but configured to perform a time-range search against the selected resource or resources.

• Table Metadata: Build ADQL - for table services which support ADQL queries. Clicking "Build ADQL" will launch the Task Runner configured for the ADQL query builder. Execute Task - will launch the Task Runner enabling the user to query the service using any provided interfaces (including "ADQL" and "Cone") if supported.

• Remote Application: Execute Task - launches the Task Runner to configure and execute the task.

The About Panel

The about panel displays the service type of the currently selected resource and, links for Further Information and emailing the Curator of the resource.