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11.1.1 Usage

The best way to see how the plot service can be used is to run the service (most simply by executing stilts server), and look at the running plot examples, along with their HTML source code, served from the server endpoint.

However this section gives a brief independent overview of how the service can be used. The PlotServlet itself exposes a RESTful API as described in Section 11.1.2. This offers the services required for client HTML/JavaScript code running in a browser to set up a plot based on server-side (or at least server-accessible) table data, and to make updates to it following user activity like mouse gestures.

A basic client JavaScript library named plot2Lib.js, that facilitates this plot setup is included with STILTS; it can be found in the stilts.jar file at uk/ac/starlink/ttools/server/plot2Lib.js, and is available from the running server at <plot-service-base>/plot2Lib.js. It exports some variables in the plot2 namespace; see comments in the file itself for documentation of how to use it. A minimal web page using this to present an interactive plot might look like:

   <html>
   <script src="plot2Lib.js"></script>
   <script>
      var serverUrl = "http://localhost:2112/stilts/plot/";
      onload = function() {
         var plotTxt = plot2.wordsToPlotTxt([
            "plot2sky",
            "layer1=mark",
            "in1=/data/catalogue.fits",
            "lon1=RA",
            "lat1=DEC"
         ]);
         var plotNode = plot2.createPlotNode(serverUrl, plotTxt);
         document.getElementsByTagName("body")[0].appendChild(plotNode);
      };
   </script>
   </html>
In this case the data file "/data/catalogue.fits" has to be available to the servlet; how this is arranged depends on the way the service is deployed.

JavaScript clients don't have to use the plot2Lib.js library; it's also possible to write custom code that talks to the RESTful API described in Section 11.1.2.


Next Previous Up Contents
Next: RESTful API
Up: Plot Service
Previous: Plot Service

STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page: http://www.starlink.ac.uk/stilts/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@jiscmail.ac.uk