Question

I'm trying to visualize sensor data in real time using C++. The sensor has an output of up to 1kHz, but gnuplot is only plotting the data at about 10Hz.

I'm using gnuplot-iostream (http://stahlke.org/dan/gnuplot-iostream/) to pipe the data to gnuplot from my C++ script, which is simple and easy. But it seems like the plotting process is slow, and takes 1/10th of a second to update the plot. Is there any way of increasing this frequency?

EDIT: Here's an example of a simple code

#include <vector>
#include <utility>
#include <gnuplot-iostream/gnuplot-iostream.h>

typedef std::pair<double, double> Point;

int main() {
  std::vector<Point> data;

  double x = 0.0;
  double y = 0.0;
  double c = 0.0;

  Gnuplot gp;
  gp << "set terminal wxt size 800, 400\n";

  while (x < 10000) {
    x += 0.01;
    y = sin(x);
    c += 0.01;
    data.push_back(Point(x,y));
    //std::cout <<  x << std::endl;
    if (c > 0.1) {
      gp << "plot '-' with lines title 'sin(x)'\n";
      gp.send1d(data);
      c = 0.0;
    }
  }

  return 0;
}

Answer 1

如果传感器以1 kHz的采样率输出数据，那绝对不意味着您应该以该频率进行绘制。太疯狂了！如果您的眼睛看不到以该频率绘制数据，那么绘制数据的重点是什么？

您应该像每隔0.1秒一样对要绘制的点进行分组，然后将它们与所有数据一起绘制。要清楚：

收集一些数据，将其放入要绘制的数组中
绘制数组的数据
在0.1秒（或0.2或0.5，或也许每100个样本中收集更多数据；这是您的要求）
将其添加到要绘制的数据数组中
可选：如果数组太大，则从前面修剪数据
绘制数据
回到3

How to increase plot frequency of gnuplot with c++ real-time data?

1 个答案: