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Technology behind the chart

  • Perl:  The data in the chart is collected from the HMS web page (http://hms.pnl.gov/stainfo.htm) and a NOAA web page (http://iwin.nws.noaa.gov/iwin/wa/hourly.html ).  A Perl script runs every 5 minutes and collects all the text from these pages and then parses out wind, temperature, and pressure data.  Perl has powerful features for manipulating text data.  This data is inserted into a MS access database on the Physics web server.  The charting application then gets its data from the database.
  • Python: The new MN data added in 2006 uses a Python script to fetch and parse XML data from this experimental (METAR) source that is provided by the developers of the ADDS interface that NOAA uses.
  • MS Access:  The Perl script populates a local MS Access database (mdb file) on the Waconia server.  The database stores the HMS data in a resolution of 15-minutes and the NOAA data in a resolution of 1 hour.  One of the charting options, delta-P, makes use of stored queries in the database that serve to join the pressure records from different sites and calculate their differential pressures.
  • NT Scheduling Service:  The Perl script is scheduled to run every ten minutes throughout the day.
  • ODBC (Open Database Connectivity):  Database connections provide the linkages for the Perl script and the ASP code to read and write to the MS Access database.
  • MDAC (Microsoft Data Access Components):  This package of components, once installed, gives you the option to use ADO, ODBC, and OLE DB.
  • Active X Data Objects (ADO):  ADO objects were used in both the Perl script and the ASP code.  The data objects support queries and manipulation of the data in the Access database.
  • ASP (Active Server Pages):  This is what makes the dynamic chart possible.  It collects the form parameters and runs queries on the local MS Access database.  It then creates a chart image (JPG file), using ASPChart.  The ASP code then acts to write the HTML code (for the web page), which includes a needed reference to the image file.
  • ASP Chart:  This is a freeware charting component for ASP.
  • VB (Visual Basic) Script:  The ASP code is primarily written in VB Script.  It's basically a subset of VBA (Visual Basic for Applications).
  • JavaScript: A small segment of the server sided ASP code (and some client side) is written in Javascript.
  • IIS:  Internet Information Server.  This is Microsoft's web server and executes the server side code of the charting (ASP) page.
  • Adobe GoLive CS2:  Editor for laying out static html pages.
  • Visual InterDev and VIM: Editors for ASP code
  • Web Browser:  The user runs the charting tool through a web browser.  The Waconia site has been tested in MS Internet Explorer and Netscape.
  • Windows 2000 Server:  This is the operating system that it all runs on.