曾經嘗試用Excel做三維散點圖，但發現Excel繪制出來的實質還是一個二維圖表，無法滿足需求，后來下載了Web圖表控件ChartDirector，剛好它支持三維散點圖樣式，做出來的效果還不錯。今天就跟大家演示一下如何用ChartDirector創建三維散點圖。

三維散點圖效果：

主要有以下幾個步驟：

1、用ThreeDScatterChart.ThreeDScatterChart創建一個ThreeDScatterChart對象
2、用ThreeDChart.setPlotRegion指定繪圖區域的位置和大小
3、用ThreeDScatterChart.addScatterGroup向圖表添加一組散點。在本例中，標記顏色設置為SameAsMainColor，顏色會根據Z坐標的顏色軸進行變化，顏色軸的訪問可以用ThreeDChart.colorAxis。
4、用ThreeDChart.setColorAxis設置顏色軸的位置
5、分別用BaseChart.addTitle 和 Axis.setTitle添加圖表和軸標題
6、最后用BaseChart.makeChart生成圖表

下面是ChartDirector生成三維散點圖的部分代碼：

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The XYZ data for the 3D scatter chart as 3 random data series
    RanSeries *r = new RanSeries(0);
    DoubleArray xData = r->getSeries(100, 100, -10, 10);
    DoubleArray yData = r->getSeries(100, 0, 0, 20);
    DoubleArray zData = r->getSeries(100, 100, -10, 10);

    // Create a ThreeDScatterChart object of size 720 x 600 pixels
    ThreeDScatterChart *c = new ThreeDScatterChart(720, 600);

    // Add a title to the chart using 20 points Times New Roman Italic font
    c->addTitle("3D Scatter Chart (1)  ", "timesi.ttf", 20);

    // Set the center of the plot region at (350, 280), and set width x depth x
    // height to 360 x 360 x 270 pixels
    c->setPlotRegion(350, 280, 360, 360, 270);

    // Add a scatter group to the chart using 11 pixels glass sphere symbols, in
    // which the color depends on the z value of the symbol
    c->addScatterGroup(xData, yData, zData, "", Chart::GlassSphere2Shape, 11,
        Chart::SameAsMainColor);

    // Add a color axis (the legend) in which the left center is anchored at (645,
    // 270). Set the length to 200 pixels and the labels on the right side.
    c->setColorAxis(645, 270, Chart::Left, 200, Chart::Right);

    // Set the x, y and z axis titles using 10 points Arial Bold font
    c->xAxis()->setTitle("X-Axis Place Holder", "arialbd.ttf", 10);
    c->yAxis()->setTitle("Y-Axis Place Holder", "arialbd.ttf", 10);
    c->zAxis()->setTitle("Z-Axis Place Holder", "arialbd.ttf", 10);

    // Output the chart
    c->makeChart("threedscatter.png");

    //free up resources
    delete r;
    delete c;
    return 0;
}