<!DOCTYPE HTML> <html> <head> <title>Graph2d | Interpolation</title> <link href="../../dist/vis.css" rel="stylesheet" type="text/css" /> <style type="text/css"> body, html { font-family: sans-serif; } </style> <script src="../../dist/vis.js"></script> <script>(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)})(window,document,'script','//www.google-analytics.com/analytics.js','ga');ga('create', 'UA-61231638-1', 'auto');ga('send', 'pageview');</script></head> <body> <h2>Graph2d | Interpolation</h2> <div style="width:700px; font-size:14px; text-align: justify;"> The Graph2d makes use of <a href="http://en.wikipedia.org/wiki/Centripetal_Catmull%E2%80%93Rom_spline" target="_blank">Catmull-Rom spline interpolation</a>. The user can configure these per group, or globally. In this example we show all 4 possiblities. The differences are in the parametrization of the curves. The options are <code>uniform</code>, <code>chordal</code> and <code>centripetal</code>. Alternatively you can disable the Catmull-Rom interpolation and a linear interpolation will be used. The <code>centripetal</code> parametrization produces the best result (no self intersection, yet follows the line closely) and is therefore the default setting. <br /><br /> For both the <code>centripetal</code> and <code>chordal</code> parametrization, the distances between the points have to be calculated and this makes these methods computationally intensive if there are very many points. The <code>uniform</code> parametrization still has to do transformations, though it does not have to calculate the distance between point. Finally, the linear interpolation is the fastest method. For more on the Catmull-Rom method, <a href="http://www.cemyuksel.com/research/catmullrom_param/catmullrom.pdf" target="_blank">C. Yuksel et al. have an interesting paper titled ″On the parametrization of Catmull-Rom Curves″</a>. </div> <br /> <div id="visualization"></div> <script type="text/javascript"> // create a dataSet with groups var names = ['centripetal', 'chordal', 'uniform', 'disabled']; var groups = new vis.DataSet(); groups.add({ id: 0, content: names[0], options: { drawPoints: false, interpolation: { parametrization: 'centripetal' } }}); groups.add({ id: 1, content: names[1], options: { drawPoints: false, interpolation: { parametrization: 'chordal' } }}); groups.add({ id: 2, content: names[2], options: { drawPoints: false, interpolation: { parametrization: 'uniform' } } }); groups.add({ id: 3, content: names[3], options: { drawPoints: { style: 'circle' }, interpolation: false }}); var container = document.getElementById('visualization'); var dataset = new vis.DataSet(); for (var i = 0; i < names.length; i++) { dataset.add( [ {x: '2014-06-12', y: 0 , group: i}, {x: '2014-06-13', y: 40, group: i}, {x: '2014-06-14', y: 10, group: i}, {x: '2014-06-15', y: 15, group: i}, {x: '2014-06-15', y: 30, group: i}, {x: '2014-06-17', y: 10, group: i}, {x: '2014-06-18', y: 15, group: i}, {x: '2014-06-19', y: 52, group: i}, {x: '2014-06-20', y: 10, group: i}, {x: '2014-06-21', y: 20, group: i} ]); } var options = { dataPoints: false, dataAxis: {visible: false}, legend: true, start: '2014-06-11', end: '2014-06-22' }; var graph2d = new vis.Graph2d(container, dataset, groups, options); </script> </body> </html>