Question

When working with the pie chart in Google Charts it seems to ignore items with a value of zero. I would really like to get these items to show up in the legend even though their value is zero so that the users knows that it was a possible answer to the question. Is there a way to have a zero value item still show up in the legend?

Answer 1

Setting the slice visibility threshold to 0 solved it for me. Notice the last option sliceVisibilityThreshold.

var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
chart.draw(data, {
    title:'How Much Pizza I Ate Last Night',
    width:400,
    height:300,
    sliceVisibilityThreshold:0
});

(taken from the sample pie chart).

By default, the threshold is set to 1/720, which means (from the docs):

The slice relative part, below which a slice will not show individually. All slices that
have not passed this threshold will be combined to a single slice, whose size is the sum
of all their sizes. Default is not to show individually any slice which is smaller than
half a degree.