A "Fan" Line chart

This is an example of the filled range chart being used to create a "Fan" chart. Fan charts are used, for example, to illustrate growing uncertainty of future values.

This goes in the documents header:

<script src="RGraph.common.core.js"></script>
<script src="RGraph.common.dynamic.js"></script>
<script src="RGraph.common.tooltips.js"></script>
<script src="RGraph.line.js"></script>

Put this where you want the chart to show up:

<canvas id="cvs" width="600" height="250">
    [No canvas support]
</canvas>

This is the code that generates the chart:

<script>
    window.onload = function ()
    {
        /**
        * Starting with the February 2013 release you'll be able to chain Set() calls
        */
        var central_line_data = [10,13,15,15,24,19,18,16,17,18,12,11];
        
        var variance1 = [0,0,1,1,2,3,4,4,4,5,5,5];
        var variance2 = [0,0,1,1,3,4,5,5,5,6,6,6];
        var variance3 = [0,0,1,1,3,4,6,6,6,7,7,7];
        
        var d1 = [];
        var d2 = [];
        var d3 = [];
        var d4 = [];
        var d5 = [];
        var d6 = [];
        
        for (var i=0; i<central_line_data.length; ++i) {
            d1.push(central_line_data[i] + variance1[i]);
            d2.push(central_line_data[i] - variance1[i]);
            
            d3.push(central_line_data[i] + variance2[i]);
            d4.push(central_line_data[i] - variance2[i]);
            
            d5.push(central_line_data[i] + variance3[i]);
            d6.push(central_line_data[i] - variance3[i]);
        }

        var line1 = new RGraph.Line({
            id: 'cvs',
            data: [d5, d6],
            options: {
                noxaxis: true,
                textSize: 14,
                filled: true,
                filledRange: true,
                fillstyle: 'rgba(255,0,0,0.1)',
                colors: ['rgba(0,0,0,0)'],
                linewidth: 0,
                ymax: 30,
                ylabels: false,
                noaxes: true,
                backgroundGridAutofitNumvlines: 11,
                hmargin: 5,
                tickmarks: null,
                textAccessible: true
            }
        }).draw()

        var line2 = new RGraph.Line({
            id: 'cvs',
            data: [d3, d4],
            options: {
                noxaxis: true,
                textSize: 14,
                filled: true,
                filledRange: true,
                fillstyle: 'rgba(255,0,0,0.2)',
                colors: ['rgba(0,0,0,0)'],
                linewidth: 0,
                ymax: 30,
                ylabels: false,
                noaxes: true,
                backgroundGridAutofitNumvlines: 11,
                hmargin: 5,
                tickmarks: null,
                textAccessible: true
            }
        }).draw()


        var line3 = new RGraph.Line({
            id: 'cvs',
            data: [d1, d2],
            options: {
                noxaxis: true,
                textSize: 14,
                filled: true,
                filledRange: true,
                fillstyle: 'rgba(255,0,0,0.4)',
                colors: ['rgba(0,0,0,0)'],
                linewidth: 3,
                ymax: 30,
                ylabels: false,
                noaxes: true,
                backgroundGrid: false,
                hmargin: 5,
                tickmarks: null,
                textAccessible: true
            }
        }).draw()

        var line4 = new RGraph.Line({
            id: 'cvs',
            data: central_line_data,
            options: {
                noxaxis: true,
                textSize: 14,
                backgroundGrid: false,
                labels: ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'],
                tooltips: ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'],
                colors: ['black'],
                linewidth: 3,
                ymax: 30,
                numxticks: 11,
                tickmarks: null,
                hmargin: 5,
                shadow: false,
                textAccessible: true
            }
        }).draw();
    };
</script>