Hello Wei-Ming,

Thanks for posting your question in the Support Forum.

To change the default sort order you will want to modify the sort operator on the haloLayout and/or the haloSliceLayout. These are both d3.layout.pie objects and here is a link on how to modify the sorts

https://github.com/d3/d3/wiki/Pie-Layout

The code in vizuly can be found at lines 151 and 157 in “src/viz/halo.js” function measure();

` // Set our halo layout properties
haloLayout.padAngle(scope.padAngle*radian)
.startAngle(0)
.endAngle(360*radian)
.value(function (d) { return d.value; });

// Set our halo slice layout properties
haloSliceLayout.value(scope.value).padAngle(0);`

– Tom