This HOWTO covers the use of the structured Data Query Interface as implemented in version 0.8.5. Newer version of the interface may differ in functionality but this document will always be updated to cover the latest version.

Preparing a Query

• Navigate to the query interface. Hover over the Data Query link on the top taskbar, then scroll down to the GSFC Interface menu item.
• The Query Builder
  

  When you have selected the GSFC Interface link, you will be sent to the Query Builder panel. The Query Builder comprises the Query Term Tree in the gray box and the Current Query listed between two buttons that submit a query to the VMO server. If this is your first time using Query Builder, it will look like in the figure where the tree is mostly collapsed and the current query lists Any data, indicating that the server would return any data available in the VMO database.

  
  
• Selecting Query Terms
  

  The plus and minus signs in the Query Term Tree expand and collapse given branches so you can display only the terms of interest. The question marks next to data products provide quick access to detailed description extracted from SPASE metadata. To select a query term or a constraint, simply click on it.

  
  
• The Query
  

  Let's build a query that will find WIND MFI data available in January 2000 that were measured at X_GSM < 0 and -5 R_E <= Y_GSM <= 5 R_E. First, to select the query constraints, click on the WIND Magnetic Field Investigation (MFI), Date/Time and Position GSM links (the order is unimportant). The Current Query now lists the selected terms.

  
  

  Next, fill in the desired time and position.All field values are reset to default when a new constraint is selected. Therefore, select constraints first and then fill in field values, i.e. just before you press the Submit button.

  
  

  The [-] and [+] links next to the selected query terms remove the constraint or add another one of the same type, respectively. The special value INF or -INF stands for positive or negative infinity, respectively. The use of INF or -INF effectively allows you to disable a minimum/maximum position check for a specific component.

• Query Submission
  

  Press either of the Submit buttons, one is located at the top of the query listing while the second button is at the bottom of the page. A message Searching database is displayed while the query is processed.

Query Results

• The Results Table

  Query results are displayed in a table with several columns. The first field holds a file number in the result set. Next field lists time intervals within the file that match the query. Then follows the file name as a direct link for downloading the data. The [?] link leads to detailed description of the data file and its origin. This information is extracted from SPASE metadata. The last column provides the name of a data product to which the data file belongs.

  
  

  To modify the query, it is best to use the Back to Query Builder link at the top of the results page. When the Back button on the web browser is used instead, a constraint (time, position, etc.) may be automatically added to the query.