Flot add marker to line on graph

Im trying to draw a graph which represents a persons weight(y axis) over time(x axis). I also need to show a marker for an event such as a change in medication on a specific day. Is it possible to add a point to the dataseries with only a time value that gets included in the line drawing but do开发者_StackOverflow中文版esnt change the drawing of the line?

You can use markings to display a line or a interval in the chart

Here is an example: http://people.iola.dk/olau/flot/examples/annotating.html

Basicly you just add this to add a vertical line:

var myPlot = $.plot(element, data, {
  grid: {
    markings: [
      { color: '#000', lineWidth: 1, xaxis: { from: 2, to: 2 } },
    ]
  }
});

This will draw a black vertical line with width 1px at x=2

There is a Flot Symbols plugin that allows you to customize the shape of the point via a callback. You could then just plot that in a second series on the same axis, and set show lines = false.

Symbols plugin: http://code.google.com/p/flot/source/browse/trunk/jquery.flot.symbol.js?r=263 Please note this this link provides the source code for the flot symbol plugin.So please search under the source link until you find the jquery.flot.symbol.js file.

Here is the example from the current Flot website: Using other symbols than circles for points (with symbol plugin). Investigating it's sourcecode might be a start point to the right direction.

Why don't you just add another series for markers and set the points to be x = the marker date, y = 0?

I needed the y value to be on the line not on the bottom of the graph. i ended up getting the two closest dates before and after the marker and working out the y intercept and then adding that as the y value and it shows up exactly where it should