Excel – How to add a vertical line in a horizontal bar chart

The problem here is that if there are too many data bars the labels will not show.

To fix this, under the "Chart Axis" properties set the Interval value to "=1". Then all the labels will be shown.

Usually comes down to how you pass the data. With arrayToDataTable your dates are just strings. If you instantiate a JS date object and build the dataTable you should get better results. This code works for me (see it live):

function drawVisualization() {

var data = new google.visualization.DataTable();

data.addColumn('datetime', 'Time of Day');
data.addColumn('number', 'Some Measurement');

data.addRows([
  [new Date(2012,10,3,11,30,0), 12],
  [new Date(2012,10,3,11,45,0), 2],
  [new Date(2012,10,3,12,1,0), 16],
  [new Date(2012,10,3,12,15,0), 3],
  [new Date(2012,10,3,12,30,0), 12],
  [new Date(2012,10,3,12,45,0), 7]
]);


new google.visualization.LineChart(document.getElementById('visualization')).
  draw(data, {curveType: "function",
              width: 500, height: 400,
              vAxis: {maxValue: 10}}
      );
}

I used to be a fan of Google Visualization but have been burned too many times by their unannounced updates. It also has a lot of limitations. Check out Dygraph which handles time series very well.