/**
* Given that the center point and the axis are set, calculate the new lat/lon points all around
* the ellipse from the center.
*/
public float[] createLatLonPoints() {
// First, need to calculate the lat/lon points for the
// ellipse.
int i;
int nMax = 72;
double angle = -Math.PI;
double angleInc = 2.0 * Math.PI / nMax;
double[] distance = new double[nMax + 1];
double x;
double y;
double a;
double b;
float[] azimuth = new float[nMax + 1];
float[] llPoints = new float[2 * (nMax + 1)];
a = majorAxisSpan / 2.0;
b = minorAxisSpan / 2.0;
for (i = 0; i < nMax; i++) {
x = Math.sqrt((a * a * b * b) / ((b * b) + ((a * a) * Math.pow(Math.tan(angle), 2))));
double yt = (x * x) / (a * a);
if (yt > 1.0) {
yt = 1.0;
}
y = Math.sqrt((1.0 - yt) * (b * b));
distance[i] = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
azimuth[i] = (float) angle + com.bbn.openmap.MoreMath.HALF_PI + (float) getRotationAngle();
if (Debug.debugging("ellipse")) {
Debug.output(
" "
+ i
+ " "
+ (azimuth[i] * 180 / Math.PI)
+ " ( "
+ distance[i]
+ " ) "
+ (Debug.debugging("ellipsedetail")
? ("[from x:" + x + ", y:" + y + ", a:" + a + ", b:" + b + "]")
: ""));
}
angle += angleInc;
}
distance[nMax] = distance[0];
azimuth[nMax] = azimuth[0];
int nCounter = 0;
for (i = 0; i < nMax + 1; i++) {
LatLonPoint llPt =
GreatCircle.spherical_between(
center.radlat_, center.radlon_, (float) distance[i], azimuth[i]);
llPoints[nCounter++] = llPt.radlat_;
llPoints[nCounter++] = llPt.radlon_;
}
return llPoints;
}