[rrd-users] tagging a chart's data?

[Bart Van Der Meerssche]

Hello everybody,

At Jokamajo we're currently developing a social metering application 
called Flukso. Participants to the trial have a DIN-rail energy meter 
installed in their electricity cabinet. A modded wireless router reports 
measurements in 5 minute intervals to the site. Flukso then lets you 
compare your total electricity consumption to that of other households. 
With Flukso, we're trying to turn those abstract watts and kWh's into 
something more tangible. You can display time-series charts covering the 
most recent hour, day, month or year. You can also dynamically add or 
remove other Fluksonians to the chart. You can check it out here: 
www.flukso.net. Note: Due to privacy reasons, we're only showing my 
consumption pattern.

You've probably noticed we're making ample use of rrdtool in the 
application. Thank you for developing such a great tool in open-source 
mode! We're doing likewise for Flukso.

We're now looking into ways to allow users to add annotations to the 
charts. One display option involves tagging the data like they do in 
google finance: http://finance.google.com/finance?client=ob&q=GOOG. We 
did find a way to add a vertical line at a certain timestamp through 
VRULE. But is there a way to add a label to the VRULE like they did in 
this flex chart: 
http://tomgutz.wordpress.com/2007/12/17/flex-custom-chart? Or does 
someone know of a better solution for tagging a chart's data?

Best regards,
Bart Van Der Meerssche.