绘制 xy 平面上两点之间的航向

发布于 2024-11-26 21:26:23 字数 771 浏览 0 评论 0原文

我正在尝试实现一个小型雷达，它根据纬度和经度坐标绘制目标，类似于 Layar AR iPhone 应用程序中的雷达。我有指南针和位置管理器来获取纬度/经度、航向和两点之间的距离。但是我在将点绘制到 xy 平面上时遇到问题。你能指出我正确的方向吗（可以这么说）？

这是我用来绘图的方法，但结果不正确：

-(void) addTargetIndicatorWithHeading:(float)heading andDistance:(float)distance{
    //draw target indicators
    //need to convert radians and distance to cartesian coordinates
    float radius = 50;
    float x0 = 0.0; 
    float y0 = 0.0;

    //convert heading from radians to degrees
    float angle = heading * (180/M_PI);

    //x-y coordinates
    float x1 = (x0 + radius * sin(angle)); 
    float y1 = (y0 + radius * cos(angle)); 

    TargetIndicator *ti = [[TargetIndicator alloc] initWithFrame:CGRectMake(x1, y1, 5, 5)];
    [self addSubview:ti];
    [ti release];

}

原文

I'm trying to implement a small radar that plots targets based on latitude and longitude coordinates similar to the radar in the Layar AR iPhone app. I have the compass and locationManager working to get the lat/lon, heading and distance between two points. However I'm having trouble plotting the points onto the x-y plane. Could you point me in the right direction(so-to-speak)?

This is the method that I am using to plot but the results are not correct:

-(void) addTargetIndicatorWithHeading:(float)heading andDistance:(float)distance{
    //draw target indicators
    //need to convert radians and distance to cartesian coordinates
    float radius = 50;
    float x0 = 0.0; 
    float y0 = 0.0;

    //convert heading from radians to degrees
    float angle = heading * (180/M_PI);

    //x-y coordinates
    float x1 = (x0 + radius * sin(angle)); 
    float y1 = (y0 + radius * cos(angle)); 

    TargetIndicator *ti = [[TargetIndicator alloc] initWithFrame:CGRectMake(x1, y1, 5, 5)];
    [self addSubview:ti];
    [ti release];

}

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墟烟 2024-12-03 21:26:23

我猜问题在于当前视图的原点坐标未添加到您的坐标中。
只需通过添加当前视图（将 ti 添加为子视图）的 origin.x 和 origin.y 来修改 x1 和 y1 。

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分开我的手 2024-12-03 21:26:23

我弄清楚出了什么问题，但我不知道其背后的原因。首先，我不应该将弧度转换为度数。这给了我正确的定位，但它旋转了 180 度。因此，为了解决这个问题，我从 PI 中减去弧度。

这是解决方案：

-(void) addTargetIndicatorWithHeading:(float)heading andDistance:(float)distance{
    //draw target indicators
    //need to convert radians and distance to cartesian coordinates
    float radius = 50;

    //origin offset
    float x0 = 50.0; 
    float y0 = 50.0;

    //convert heading from radians to degrees and rotate by 180 deg
    float angle = M_PI - heading; 

    float x1 = (x0 + radius * sin(angle));   
    float y1 = (y0 + radius * cos(angle)); 

    TargetIndicator *ti = [[TargetIndicator alloc] initWithFrame:CGRectMake(x1, y1, 5, 5)];
    [self addSubview:ti];
    [ti release];


}

I figured out what was wrong but I'm don't know the reasoning behind it. First I should not have been converting the radians to degrees. This gives me the correct positioning but it is rotated 180 degrees. So to fix it, I subtract the radians from PI.

Here is the solution:

-(void) addTargetIndicatorWithHeading:(float)heading andDistance:(float)distance{
    //draw target indicators
    //need to convert radians and distance to cartesian coordinates
    float radius = 50;

    //origin offset
    float x0 = 50.0; 
    float y0 = 50.0;

    //convert heading from radians to degrees and rotate by 180 deg
    float angle = M_PI - heading; 

    float x1 = (x0 + radius * sin(angle));   
    float y1 = (y0 + radius * cos(angle)); 

    TargetIndicator *ti = [[TargetIndicator alloc] initWithFrame:CGRectMake(x1, y1, 5, 5)];
    [self addSubview:ti];
    [ti release];


}

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