How to create value over time chart with Kibana 3?

Question

I use logstash to store log files containing the speed of vehicles over time.

In Kibana 3, how can I generate a panel which displays a value over time, i.e. the x axis displays the time and the y axis the related value, e.g. vehicle speed.

Most panels I found count the occurrence of events in a given time span and display it on the y axis. My goal however is to directly print a value from the json log entry (wheelSpeed_m_s), which looks as follows:

{
  "_index": "logstash-2013.05.07",
  "_type": "vehicle_odometry",
  "_id": "Q3b58Pi7RUKuPon0s_ihlA",
  "_score": null,
  "_source": {
    "message": " ",
    "wheelSpeed_m_s": 0.91,
    "@timestamp": "2013-05-07T17:50:04.099+02:00",
    "angularVelocity_rad_s": 0,
    "type": "vehicle_odometry",
    "@version": "1",
    "ts_ms": 1367934604099
  },
}

Any help is highly appreciated.

Solution

In the histogram panel, click the "Configure" (gear) icon, then select the "Panel" tab.

On that tab, you can select the "Chart value". This defaults to count, but can be any of the basic math set functions (mean, max, min, total). Select the function, and you'll be asked to enter the field to which the function should be applied:

OP: please don't accept this answer (rutter deserves the points for getting you straight). I leave the info here to complete the question so it's not marked as 'unanswered'.