Similar to plot line, but now the grid shows angular increments. See example below:
var PI = Math.PI,
cos = Math.cos,
sin = Math.sin,
pow = Math.pow;
var graph = new Graph({
appendTo : "container",
canvasWidth : 800,
canvasHeight : 800/Math.sqrt(2),
barPosition : "center",
title : "Half-wave Dipole Antenna Radiation",
yAxisTitle : "y",
xAxisTitle : "x",
polarAxisNumFormat : "deg",
polarGridNumLines : 24
});
var px = [],
py = [];
for (var theta = 0; theta <= 2*PI; theta += 0.01) {
r = 1-pow(sin(theta), 2);
r = r/2;
px.push(r*cos(theta));
py.push(r*sin(theta));
}
graph.polar(py, px);