Radius are now stored in meters, to easily account for different

radiuses on X and Y axes.
This commit is contained in:
Phyks (Lucas Verney) 2018-12-04 15:54:50 +01:00
parent df9767b65e
commit d621964863
9 changed files with 60 additions and 67 deletions

View file

@ -17,10 +17,10 @@ public final class CheapRulerSingleton {
public final static int KILOMETERS_TO_METERS = 1000;
public final static double DEG_TO_RAD = Math.PI / 180.;
// Cosine cache constants
// Scale cache constants
private final static int SCALE_CACHE_LENGTH = 1800;
private final static int SCALE_CACHE_INCREMENT = 100000;
// COS_CACHE_LENGTH cached values between 0 and COS_CACHE_MAX_DEGREES degrees.
// SCALE_CACHE_LENGTH cached values between 0 and COS_CACHE_MAX_DEGREES degrees.
private final static double[][] SCALE_CACHE = new double[SCALE_CACHE_LENGTH][];
/**
@ -33,7 +33,7 @@ public final class CheapRulerSingleton {
}
private static double[] calcKxKyFromILat(int ilat) {
double lat = DEG_TO_RAD*(ilat-90000000)/1000000.;
double lat = DEG_TO_RAD*ilat*ILATLNG_TO_LATLNG - 90;
double cos = Math.cos(lat);
double cos2 = 2 * cos * cos - 1;
double cos3 = 2 * cos * cos2 - cos;
@ -50,8 +50,8 @@ public final class CheapRulerSingleton {
/**
* Calculate the degree->meter scale for given latitude
*
* @result [lon->meter,lat->meter]
*
* @result [lon->meter,lat->meter]
*/
public static double[] getLonLatToMeterScales( int ilat ) {
return SCALE_CACHE[ ilat / SCALE_CACHE_INCREMENT ];
@ -65,12 +65,13 @@ public final class CheapRulerSingleton {
* @param ilat1 Integer latitude for the start point, this is (latitude + 90) * 1e6.
* @param ilon2 Integer longitude for the end point, this is (longitude + 180) * 1e6.
* @param ilat2 Integer latitude for the end point, this is (latitude + 90) * 1e6.
* @return The distance between the two points, in meters.
*
* @note Integer longitude is ((longitude in degrees) + 180) * 1e6.
* Integer latitude is ((latitude in degrees) + 90) * 1e6.
*/
public static double distance(int ilon1, int ilat1, int ilon2, int ilat2) {
double[] kxky = getLonLatToMeterScales( ( ilat1 + ilat2 ) >> 1 );
double[] kxky = getLonLatToMeterScales( ( ilat1 + ilat2 ) >> 1 );
double dlon = (ilon1 - ilon2) * kxky[0];
double dlat = (ilat1 - ilat2) * kxky[1];
return Math.sqrt(dlat * dlat + dlon * dlon); // in m