4.2. MultiGraphlet Station Specification

In order to display data from a network, MultiGraphlet needs information about the stations in the network. It uses this station information to create a drop-down selection box to allow the user to choose which station to graph data from, and in constructing the requests that it sends to the data server when requesting data for that station.

MultiGraphlet gets this station information by sending an HTTP request over the internet to a "station server". The station server is a program that responds with a list of the stations in an XML format. The format of the list is like the following:

  <stationlist>
    <station>
      <id>1007</id>
      <name>AK Barrow 4 ENE</name>
      <timezone>US/Alaska</timezone>
    </station>
    ...
  </stationlist>

There can be any number of stations in the list; each one is delimited by <station> and </station>. Each station has an "id", a "name", and a "timezone". The "id" is an integer that uniquely identifies a station, the "name" is a name for the station that MultiGraphlet displays at the top of the graph in the legend, and in the drop-down station selection box, and "timezone" is the time zone that the station is in. MultiGraphlet uses the time zone to determine what time zone to display times in. (The user can change this with the time zone drop-down box.)

The time zone should be specified using a "long" time zone name, like "US/Eastern", rather than a short 3-letter abbreviation, like "EST". The list of US time zones in this format is: "US/Alaska", "US/Arizona", "US/Central", "US/East-Indiana", "US/Eastern", "US/Mountain", and "US/Pacific". Greenwich Mean Time may be specified as either "UTC" or "GMT". For a complete list of time zone names, see Appendix B.

The station server is specified to MultiGraphlet in the "station_url" applet parameter; see Section 4.5 for details.

The station server URL takes no parameters --- it simply produces a list of stations in the above XML format. If the list of stations never changes, it can be the URL of a static file.

If your "network" consists of just one station, or of too many (hundreds, or thousands) to practically display in a drop-down box, you can use the applet parameters to tell MultiGraphlet to omit the drop-down box and simply display data from one station. See Section 4.5 for details.