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Technology behind the chart

This describes the components used in the original Rosy.asp charting page (see related discussion in the installation guide).

• Data-Collection Scripts
  • Perl: Some of the data behind the chart is gleaned (screen scraped) from web pages. Please refer to the FAQ on data sources. This includes the HMS web page and the two NOAA web pages. 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 useful features for manipulating text data. This data is inserted into a MS Access database on the server. The charting application then gets its data from the database.
  • Python: The MN data added in 2006 uses a scheduled Python script to download and parse METAR data from an XML data feed.
• Database Connectivity
  • MDAC (Microsoft Data Access Components): This package of components, once installed, gives you the option to use ODBC and ADO.
    • ODBC (Open Database Connectivity): Database connections provide the linkages for the Perl and Python scripts and the ASP code to read and write to the MS Access database.
    • 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.
• MS Access: The Perl script populates a local MS Access database (mdb file) on the 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 SQL queries that serve to join the pressure records from different sites and calculate their differential pressures.
• Charting Scripts
  • Server-Sided
    • 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.
    • VBScript (Visual Basic Scripting Edition): The ASP code is primarily written in VBScript which is a subset of VBA (Visual Basic for Applications).
    • ASP Chart: This is a freeware charting component for ASP. It produces the chart image.
    • JavaScript: A portion of the server sided ASP code is written in Javascript.
  • Client-Sided
    • JavaScript: Client code that runs in the browser is written in JavaScript. An example of this is the code that supports the timer function.
• Editors
  • Microsoft Expression Web: Editor for laying out static HTML pages.
  • Notepad++ and VIM: Editors for the code.
• Operating System: It all runs on MS Windows 7, 8 or 10.
  • IIS: Internet Information Server. This is Microsoft's web server and executes the server-sided code of the charting page (ASP).
  • MS Window's Scheduling Service: The Perl and Python gleaner scripts are scheduled to run every five minutes throughout the day.