Java Swing - 在 JPanel 上使用 GPS 坐标绘制站点名称

Question

我正在做一项作业，但在某个时候卡住了。我得到了一个包含一系列站点的 .txt 文件，我应该使用给我的 GPS 坐标绘制站点名称，但我无法将这些坐标转换为 JPanel 使用。此外，GPS 坐标以 doubles 写入，但 XY 坐标以 ints 写入。我怎样才能做到这一点？

这是无效的代码。

     void extents() {
 minLong = Double.MAX_VALUE;
 minLat = Double.MAX_VALUE;
 maxLong = -Double.MIN_VALUE;
 maxLat = -Double.MIN_VALUE;

for(Station station : stations){

    if(station.getLatitude()>maxLat){
        maxLat = station.getLongitude();
        maxLong = station.getLongitude();
    }
    if(station.getLatitude()<minLat){
        minLat = station.getLongitude();
        minLong = station.getLongitude();
    }
    if(station.getLongitude()>maxLong){
        maxLong = station.getLongitude();
    }
    if(station.getLongitude()<minLong){
        minLong = station.getLongitude();
    }
}

我正在尝试使用以下方法绘制它们：

 for (int i = 0; i < stations.size(); i++) {

       double scalingFactorx = width/(maxLat - minLat);
double scalingFactory = height/(maxLong - minLong);
double scalingFactor = Math.min(scalingFactorx, scalingFactory);

double drawingX = stations.get(i).getLatitude() * scalingFactor;
double drawingY = stations.get(i).getLongitude() * scalingFactor;
double drawingY2 = height - drawingY; 
gr.drawString(stations.get(i).getName(), (int)drawingX/100, (int)drawingY2/200);
      }

我现在得到每个站的不同坐标，但是，它们仍然太近，这意味着它们没有按比例缩放到 JPanel。

谢谢！

Answer 1

嗯，
首先，你应该让最小值和最大值成为站点的实际最小值和最大值：

double minLong = Double.MAX_VALUE;
double minLat = Double.MAX_VALUE;
double maxLong = -Double.MIN_VALUE;
double maxLat = -Double.MIN_VALUE;

for(Station station : stations){

    if(station.getLatitude()>maxLat){
        maxLat = station.getLongitude();
        maxLong = station.getLongitude();
    }
    if(station.getLatitude()<minLat){
        minLat = station.getLongitude();
        minLong = station.getLongitude();
    }
    if(station.getLongitude()>maxLong){
        maxLong = station.getLongitude();
    }
    if(station.getLongitude()<minLong){
        minLong = station.getLongitude();
    }
}

然后您可以在绘制方法中执行此操作：

for (int i = 0; i < stations.size(); i++) {

    double scalingFactorx = width/(maxLat - minLat);
    double scalingFactory = height/(maxLong - minLong);
    double scalingFactor = Math.min(scalingFactorx, scalingFactory);

    double drawingX = (stations.get(i).getLatitude() - minLat)/(maxLat-minLat);
    double drawingY = (stations.get(i).getLongitude() - minLong)/(maxLong-minLong);
    //double drawingY2 = height - drawingY; This line isn't needed. It causes the text to be drawn outside the jpanel.
    gr.drawString(stations.get(i).getName(), (int)drawingX, (int)drawingY);

}

现在，它所做的是找到最右边和最左边的站点以及最高和最低的位置，然后缩放所有内容以适合。

Answer 2

   for (int i = 0; i < stations.size(); i++) {

    extents();

    scalingFactorx = width/(maxLat - minLat);
    scalingFactory = height/(maxLong - minLong);
    scalingFactor = Math.min(scalingFactorx, scalingFactory);

    drawingX = (stations.get(i).getLatitude() - minLat)   * scalingFactorx;
    drawingY = (stations.get(i).getLongitude() - minLong)  * scalingFactory;
    drawingY2 = height - drawingY; 
    gr.drawString(stations.get(i).getName(), (int)drawingX, (int)drawingY2);

像这样应该可以解决问题。

Java Swing - 在 JPanel 上使用 GPS 坐标绘制站点名称

Java Swing - Draw Station Names using GPS Coordinates on JPanel

java

graphics

swing

jpanel