/**
* Convert lat/lon coordinates to projection coordinates.
*
* @param from array of lat/lon coordinates: from[2][n], where (from[0][i], from[1][i]) is the
* (lat,lon) coordinate of the ith point
* @param to resulting array of projection coordinates: to[2][n] where (to[0][i], to[1][i]) is the
* (x,y) coordinate of the ith point
* @return the "to" array
*/
public double[][] projToLatLon(double[][] from, double[][] to) {
int cnt = from[0].length;
double[] fromXA = from[INDEX_X];
double[] fromYA = from[INDEX_Y];
double[] toLatA = to[INDEX_LAT];
double[] toLonA = to[INDEX_LON];
double toLat, toLon;
for (int i = 0; i < cnt; i++) {
double fromX = fromXA[i];
double fromY = fromYA[i];
double rho = Math.sqrt(fromX * fromX + fromY * fromY);
double c = Math.asin(rho / R);
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c) * sinLat0 + (fromY * Math.sin(c) * cosLat0 / rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho * cosLat0 * Math.cos(c) - fromY * sinLat0 * Math.sin(c);
toLon = lon0 + Math.atan(fromX * Math.sin(c) / temp);
} else if (lat0 == PI_OVER_4) {
toLon = lon0 + Math.atan(fromX / -fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX / fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat = Math.toDegrees(toLat);
toLon = Math.toDegrees(toLon);
if (temp < 0) {
toLon += 180;
}
toLon = LatLonPointImpl.lonNormal(toLon);
toLatA[i] = toLat;
toLonA[i] = toLon;
}
return to;
}
/**
* Convert projection coordinates to a LatLonPoint Note: a new object is not created on each call
* for the return value.
*
* @param world convert from these projection coordinates
* @param result the object to write to
* @return LatLonPoint convert to these lat/lon coordinates
*/
public LatLonPoint projToLatLon(ProjectionPoint world, LatLonPointImpl result) {
double toLat, toLon;
double fromX = world.getX();
double fromY = world.getY();
double rho = Math.sqrt(fromX * fromX + fromY * fromY);
double c = Math.asin(rho / R);
toLon = lon0;
double temp = 0;
if (Math.abs(rho) > TOLERANCE) {
toLat = Math.asin(Math.cos(c) * sinLat0 + (fromY * Math.sin(c) * cosLat0 / rho));
if (Math.abs(lat0 - PI_OVER_4) > TOLERANCE) { // not 90 or -90
temp = rho * cosLat0 * Math.cos(c) - fromY * sinLat0 * Math.sin(c);
toLon = lon0 + Math.atan(fromX * Math.sin(c) / temp);
} else if (lat0 == PI_OVER_4) {
toLon = lon0 + Math.atan(fromX / -fromY);
temp = -fromY;
} else {
toLon = lon0 + Math.atan(fromX / fromY);
temp = fromY;
}
} else {
toLat = lat0;
}
toLat = Math.toDegrees(toLat);
toLon = Math.toDegrees(toLon);
if (temp < 0) {
toLon += 180;
}
toLon = LatLonPointImpl.lonNormal(toLon);
result.setLatitude(toLat);
result.setLongitude(toLon);
return result;
}