Thursday, November 22, 2007

Experiences with Chronoscope

The Chronoscope online documentation is a bit thin at the moment. I am sure the guys over at Timepedia are working on the documentation, so this is likely to be improved quite soon. Here is a list of things that stroked my attention while using Chronoscope, things that are not documented but one should be aware of. Note that the Traceurl Google Gadget is a plain JSP and I have not been using the GWT or JavaScript but the Microformats version of Chronoscope instead.

  • Apparently the missing IE support is issue number one. On the Chronoscope Group Ray Cromwell said that they are 'targeting IE support in the next month or so.'

  • supports two languages (English and German) and the Traceurl Google Gadget even three languages (English, German and French), thus a proper solution for internationalization is very important for me. At the moment Chronoscope's I18N/L10N support is weak, respectively close to non existent. Ray Cromwell comment about I18N was 'We plan to support it. [..] I view I18N/L10N very important, and we will most likely be using GWT's builtin L10N features to do this efficiently.'.

  • Related to the currently missing internationalization support is the problem that the axis identifiers are not interpreted correctly. Using microformats the first row of the THEAD element specifies the axis labels. The label for the value label is set correctly, but the name of time axis is ignored. Setting the German word 'Zeit' instead of 'Time' the chart is still displaying 'Time.'

  • In the first attempt I used a HashMap to keep track of the number of accesses per day. With the effect that the generated TBODY element contained unsorted rows. That does not work, Chronoscope needs its input to be sorted by time.

  • The second thing I realized is that the input should not have gaps. The time line has to contain all dates, setting the value of the dates without accesses to zero. Otherwise Chronoscope kind of interpolates the missing values, which is obviously wrong for my accesses per day use case. For example, say we have the date 06/09/07 with 12 accesses and the date 06/11/07 with 6 accesses to a traceable URL, not setting the 10th to 0 will result in a wrong graph with an interpolated value of 9 accesses for the date 06/10/07. That is not necessarily an error, but just the way Chronoscope handles its input and something the developer needs to be aware of.

The latest release is a beta version and I am sure things will be improved with upcoming versions. The above list is not meant as criticism, but as assistance to people who want to get their hands dirty with the beta release. I am a programmer myself, so I am well aware of the tremendous amount of work that went into Chronoscope. Chronoscope rocks and I am going to use it further on. In one of the next post I will give you some insight into my implementation. A short cook-book style abstract to get you (in case you are a developer) up and running with your own Chronoscope time series chart.

Wednesday, November 21, 2007

Time series visualization in Google Gadget

I included the access time series visualization into the Traceurl Google Gadget. There is a new icon chart.gif right next to the Google Map operation in the Traceurl Google Gadget. Click on the new icon and a new window with a time series chart for the respective traceable URL is displayed.

As mentioned in the previous post the Chronoscope platform does not yet support Internet Explorer, using IE you are getting a blank page. For this reason I'm not going to add the time series functionality to the main application for now. I'll keep you up to date about future progress.

Tuesday, November 20, 2007

Time series chart

Okay, I finally got some new functionality up and running. It is not yet fully featured, because it relies on a beta version framework. The point of the new functionality is to visualize the accesses to a traceable URL on a time series chart. This is done with the help of the Chronoscope platform. Timepedia announce the first beta release of Chronoscope a couple of days ago and I have been playing around with it over the last weekend. The first shot of an access time series looks like this:

One of the coolest feature of Chronoscope can not be seen on the screenshot, it is the possibility to zoom and pan within the chart. Have a look at the demo page to see a live version, is really impressive! Chronoscope currently lacks IE support, thus the charts only work on Firefox, Safari and Opera. I hope they can fix that soon, because that is kind of a show-stopper :-(