generate spherical arc coordinates

0
votes

I want to generate a vector of spherical (Earth) coordinates that would draw an arc given center location (in longitude latitude), radius (in meters), azimuth, and angle width (in radians).

My code:

double left = azimuth - width * .5;
double right = azimuth + width * .5;
double angleStep = 0.05;
std::vector<double> arcPointsX, arcPointsY;

for (double f = left; f <= right; f += angleStep) {   
    arcPointsX.push_back(x + radius * (double)cos(f));
    arcPointsY.push_back(y + radius * (double)sin(f));
}

This produces arcs however, these arcs are not facing the correct direction when I draw them though.

Thanks for help!

1
c++mathcoordinatescomputational-geometry
How are you using xa1, ya1, xa2, and ya2? – R Sahu
same way as arcPointsX and arcPointsY, they should not really be there, I will modify the code. – Jana
What are X and Y? You seem to be drawing an arc in the plane passing through the equator, not the surface of the Earth. – Beta
X,Y is the circle center location in longitude latitude – Jana
You're trying to do too much at once. Are you comfortable with coordinate conversions between spherical (lat, lon) and Cartesian (x,y,z)? – Beta

1 Answers

1
votes

It turned out the problem was I had sin/cos the other way around. Using this gives me correct arcs:

arcPointsX.push_back(x + radius * (double)sin(f));
arcPointsY.push_back(y + radius * (double)cos(f));