ChartDirector 6.0 (C++ Edition)

Polar Vector Chart

This example demonstrates a polar vector chart.

A vector chart is like a scatter chart, but the symbols are arrows which can be of arbitrary lengths pointing to arbitrary directions. Thus each symbol in a vector chart is specified by 4 values - the radial and angular coordinates, and the length and the direction.

In ChartDirector, a polar vector layer is created using PolarChart.addVectorLayer.

Source Code Listing

[The following code is available in "cppdemo/polarvector". A MFC version of the code is available in "mfcdemo/mfcdemo" (Windows edition only). A QT version of the code is available in "qtdemo/qtdemo".]
 ```#include "chartdir.h" int main(int argc, char *argv[]) { // Coordinates of the starting points of the vectors double radius[] = {5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25}; double angle[] = {0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330}; // Magnitude and direction of the vectors double magnitude[] = {5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}; double direction[] = {60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 0, 30}; // 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 15pt Arial Bold Italic font c->addTitle("Polar Vector Chart Demonstration", "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); // Set angular axis as 0 - 360, with a spoke every 30 units c->angularAxis()->setLinearScale(0, 360, 30); // Add a polar vector layer to the chart with blue (0000ff) vectors c->addVectorLayer(DoubleArray(radius, (int)(sizeof(radius) / sizeof(radius[0]))), DoubleArray( angle, (int)(sizeof(angle) / sizeof(angle[0]))), DoubleArray(magnitude, (int)(sizeof( magnitude) / sizeof(magnitude[0]))), DoubleArray(direction, (int)(sizeof(direction) / sizeof(direction[0]))), Chart::RadialAxisScale, 0x0000ff); // Output the chart c->makeChart("polarvector.png"); //free up resources delete c; return 0; }```