Tailoring a Coordinate Mapping

When converting rectangular to polar coordinates, you can choose to map only one of the dimensions. Use the PolarCoord Type property to do this.

Mapping just a single dimension is useful for pie charts. See Example: Pie Chart.

The example below is the same as that in Converting Rectangular to Polar Coordinates, except that here only the angle dimension is mapped:

Note: Script that modifies 'graph' should be placed at the element level. See Adding Element-Level Script in Report Scripting and Adding Component Script in Dashboard Scripting for more information.

dataset = [["Direction", "Score"],[(Math.PI/2),20],[(Math.PI/4),30],[(Math.PI),35]];

graph = new EGraph();

var elem = new PointElement("Direction", "Score");

var xscale = new LinearScale("Direction");

var yscale = new LinearScale("Score");

yscale.setMin(0);

yscale.setMax(40);

var yaxis = new AxisSpec();

yaxis.setGridStyle(GraphConstants.DOT_LINE);

yscale.setAxisSpec(yaxis);

 

xscale.setMin(0);

xscale.setMax(1.95*Math.PI);

xscale.setIncrement(Math.PI/8);

var xaxis = new AxisSpec();

var tspec = new TextSpec();

tspec.setFormat(new java.text.DecimalFormat("0.0"));

xaxis.setTextSpec(tspec);

xaxis.setGridStyle(GraphConstants.DOT_LINE);

xscale.setAxisSpec(xaxis);

 

graph.setScale("Direction",xscale);

graph.setScale("Score",yscale);

var rect = new RectCoord(xscale,yscale);

var polar = new PolarCoord(rect);

polar.setType(PolarCoord.THETA);

graph.setCoordinate(polar);

graph.addElement(elem);

 

The result is that all points have the same magnitude, with variation only along the angle dimension. To reverse a mapping, use the Coordinate object's transpose() method.

<< Converting Rectangular to Polar Coordinates © 1996-2013 InetSoft Technology Corporation (v11.4) Example: Pie Chart >>