ChartDirector Ver 3.0 (C++ Edition)

Polar Scatter Chart




A polar scatter chart can be created as a polar line chart with data symbols enabled. The line width is set to 0, so only the symbols can be seen. This will create the effects of a scatter chart.

The detail steps are:

Source Code Listing

[The following project is available in "cppdemo/polarscatter".]
#include "chartdir.h" int main(int argc, char *argv[]) { //The data for the chart double data0[] = {43, 89, 76, 64, 48, 18, 92, 68, 44, 79, 71, 85}; double angles0[] = {45, 96, 169, 258, 15, 30, 330, 260, 60, 75, 110, 140}; double data1[] = {50, 91, 26, 29, 80, 53, 62, 87, 19, 40}; double angles1[] = {230, 210, 240, 310, 179, 250, 244, 199, 89, 160}; double data2[] = {88, 65, 76, 49, 80, 53}; double angles2[] = {340, 310, 340, 210, 30, 300}; //The labels on the angular axis (spokes) const char *labels[] = {"North", "North\nEast", "East", "South\nEast", "South", "South\nWest", "West", "North\nWest"}; //Create a PolarChart object of size 460 x 460 pixels PolarChart *c = new PolarChart(460, 460); //Add a title to the chart at the top left corner using 15pts Arial Bold //Italic font c->addTitle(TopLeft, "<*underline=2*>Plants in Wonderland", "arialbi.ttf", 15); //Set center of plot area at (230, 240) with radius 180 pixels c->setPlotArea(230, 240, 180); //Set the grid style to circular grid c->setGridStyle(false); //Add a legend box at the top right corner of the chart using 9 pts Arial //Bold font c->addLegend(459, 0, true, "arialbd.ttf", 9)->setAlignment(TopRight); //Set angular axis as 0 - 360, either 8 spokes c->angularAxis()->setLinearScale(0, 360, StringArray(labels, sizeof(labels)/sizeof(*labels))); //Set the radial axis label format c->radialAxis()->setLabelFormat("{value} km"); //Add a blue (0xff) polar line layer to the chart using (data0, angle0) PolarLineLayer *layer0 = c->addLineLayer(DoubleArray(data0, sizeof(data0)/sizeof(*data0)), 0xff, "Immortal Weed"); layer0->setAngles(DoubleArray(angles0, sizeof(angles0)/sizeof(*angles0))); layer0->setLineWidth(0); layer0->setDataSymbol(TriangleSymbol, 11); //Add a red (0xff0000) polar line layer to the chart using (data1, angles1) PolarLineLayer *layer1 = c->addLineLayer(DoubleArray(data1, sizeof(data1)/sizeof(*data1)), 0xff0000, "Precious Flower"); layer1->setAngles(DoubleArray(angles1, sizeof(angles1)/sizeof(*angles1))); //Disable the line by setting its width to 0, so only the symbols are //visible layer1->setLineWidth(0); //Use a 11 pixel diamond data point symbol layer1->setDataSymbol(DiamondSymbol, 11); //Add a green (0x00ff00) polar line layer to the chart using (data2, //angles2) PolarLineLayer *layer2 = c->addLineLayer(DoubleArray(data2, sizeof(data2)/sizeof(*data2)), 0xff00, "Magical Tree"); layer2->setAngles(DoubleArray(angles2, sizeof(angles2)/sizeof(*angles2))); //Disable the line by setting its width to 0, so only the symbols are //visible layer2->setLineWidth(0); //Use a 9 pixel square data point symbol layer2->setDataSymbol(SquareSymbol, 9); //output the chart c->makeChart("polarscatter.png"); //free up resources delete c; return 0; }