Calculate latitude and longitude having meters distance from another latitude/longitude point

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失恋的感觉
失恋的感觉 2020-12-31 12:29

I need to calculate latitude and longitude of a given point.

I know latitude and longitude of a reference point, and an value indicating meters on x and y axis fro

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  • 2020-12-31 13:01

    Here is the best starting point for such questions: Aviation Formulary. They have all the formulas for doing such kinds of things.

    From these formulary, I created my own Java util class. It uses a lot of internal stuff, so I cannot post the actual class here but to give you some examples on how to convert the knowledge from the formulary into Java code.

    Here're some basic methods:

    /**
     * the length of one degree of latitude (and one degree of longitude at equator) in meters.
     */
    private static final int DEGREE_DISTANCE_AT_EQUATOR = 111329;
    /**
     * the radius of the earth in meters.
     */
    private static final double EARTH_RADIUS = 6378137; //meters
    /**
     * the length of one minute of latitude in meters, i.e. one nautical mile in meters.
     */
    private static final double MINUTES_TO_METERS = 1852d;
    /**
     * the amount of minutes in one degree.
     */
    private static final double DEGREE_TO_MINUTES = 60d;
    
    
    /**
     * This method extrapolates the endpoint of a movement with a given length from a given starting point using a given
     * course.
     *
     * @param startPointLat the latitude of the starting point in degrees, must not be {@link Double#NaN}.
     * @param startPointLon the longitude of the starting point in degrees, must not be {@link Double#NaN}.
     * @param course        the course to be used for extrapolation in degrees, must not be {@link Double#NaN}.
     * @param distance      the distance to be extrapolated in meters, must not be {@link Double#NaN}.
     *
     * @return the extrapolated point.
     */
    public static Point extrapolate(final double startPointLat, final double startPointLon, final double course,
                                    final double distance) {
        //
        //lat =asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc))
        //dlon=atan2(sin(tc)*sin(d)*cos(lat1),cos(d)-sin(lat1)*sin(lat))
        //lon=mod( lon1+dlon +pi,2*pi )-pi
        //
        // where:
        // lat1,lon1  -start pointi n radians
        // d          - distance in radians Deg2Rad(nm/60)
        // tc         - course in radians
    
        final double crs = Math.toRadians(course);
        final double d12 = Math.toRadians(distance / MINUTES_TO_METERS / DEGREE_TO_MINUTES);
    
        final double lat1 = Math.toRadians(startPointLat);
        final double lon1 = Math.toRadians(startPointLon);
    
        final double lat = Math.asin(Math.sin(lat1) * Math.cos(d12)
            + Math.cos(lat1) * Math.sin(d12) * Math.cos(crs));
        final double dlon = Math.atan2(Math.sin(crs) * Math.sin(d12) * Math.cos(lat1),
            Math.cos(d12) - Math.sin(lat1) * Math.sin(lat));
        final double lon = (lon1 + dlon + Math.PI) % (2 * Math.PI) - Math.PI;
    
        return new Point(Math.toDegrees(lat), Math.toDegrees(lon));
    }
    
    /**
     * calculates the length of one degree of longitude at the given latitude.
     *
     * @param latitude the latitude to calculate the longitude distance for, must not be {@link Double#NaN}.
     *
     * @return the length of one degree of longitude at the given latitude in meters.
     */
    public static double longitudeDistanceAtLatitude(final double latitude) {
    
        final double longitudeDistanceScaleForCurrentLatitude = Math.cos(Math.toRadians(latitude));
        return DEGREE_DISTANCE_AT_EQUATOR * longitudeDistanceScaleForCurrentLatitude;
    }
    
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  • 2020-12-31 13:03

    This isn't really an answer, but the comments box is too short for what I want to post, and this result came up quite high when I was googling around for an answer. BertNase code above is good, and I'm using it. However, there's some weirdness around the edge cases. I'm not 100% sure the code is wrong, as I'm still learning geo stuff, but I'm adding the parameters from my junit test case I wrote around it. For example longitude goes from 180 to -90 when I move south for 100m (case 10)

    /*0*/   { inputOf(0.0, 0.0), NORTH, shouldGiveAnswerOf(0.0009, 0.0) },
    /*1*/   { inputOf(0.0, 0.0), SOUTH, shouldGiveAnswerOf(-0.0009, 0.0) },
    /*2*/   { inputOf(0.0, 0.0), WEST, shouldGiveAnswerOf(0.0, -0.0009) },
    /*3*/   { inputOf(0.0, 0.0), EAST, shouldGiveAnswerOf(0.0, 0.0009) },
    
    /*4*/   { inputOf(90.0, 180.0), NORTH, shouldGiveAnswerOf(89.9991, -180.0) },
    /*5*/   { inputOf(0.0, 180.0), NORTH, shouldGiveAnswerOf(0.0009, -180.0) },
    /*6*/   { inputOf(-90.0, 180.0), NORTH, shouldGiveAnswerOf(-89.9991, -180.0) },
    /*7*/   { inputOf(90.0, -180.0), NORTH, shouldGiveAnswerOf(89.9991, -180.0) },
    /*8*/   { inputOf(0.0, -180.0), NORTH, shouldGiveAnswerOf(0.0009, -180.0) },
    /*9*/   { inputOf(-90.0, -180.0), NORTH, shouldGiveAnswerOf(-89.9991, -180) },
    
    /*10*/  { inputOf(90.0, 180.0), SOUTH, shouldGiveAnswerOf(89.9991, -90.0) },
    /*11*/  { inputOf(0.0, 180.0), SOUTH, shouldGiveAnswerOf(-0.0009, -180.0) },
    /*12*/  { inputOf(-90.0, 180.0), SOUTH, shouldGiveAnswerOf(-89.9991, -90.0) },
    /*13*/  { inputOf(90.0, -180.0), SOUTH, shouldGiveAnswerOf(89.9991, -90.0) },
    /*14*/  { inputOf(0.0, -180.0), SOUTH, shouldGiveAnswerOf(-0.0009, -180.0) },
    /*15*/  { inputOf(-90.0, -180.0), SOUTH, shouldGiveAnswerOf(-89.9991, -90) },
    
    /*16*/  { inputOf(90.0, 180.0), EAST, shouldGiveAnswerOf(89.9991, -90.0) },
    /*17*/  { inputOf(0.0, 180.0), EAST, shouldGiveAnswerOf(0.0, -179.9991) },
    /*18*/  { inputOf(-90.0, 180.0), EAST, shouldGiveAnswerOf(-89.9991, -90.0) },
    /*19*/  { inputOf(90.0, -180.0), EAST, shouldGiveAnswerOf(89.9991, -90.0) },
    /*20*/  { inputOf(0.0, -180.0), EAST, shouldGiveAnswerOf(0.0, -179.9991) },
    /*21*/  { inputOf(-90.0, -180.0), EAST, shouldGiveAnswerOf(-89.9991, -90) },
    
    /*22*/  { inputOf(10.0, 5.0), NORTH, shouldGiveAnswerOf(10.0009, 5.0) },
    /*23*/  { inputOf(10.0, 5.0), SOUTH, shouldGiveAnswerOf(9.9991, 5.0) },
    /*24*/  { inputOf(10.0, 5.0), WEST, shouldGiveAnswerOf(10.0, 4.999086) },
    /*25*/  { inputOf(10.0, 5.0), EAST, shouldGiveAnswerOf(10.0, 5.000914) },
    
    /*26*/  { inputOf(10.0, 5.0), NORTH_EAST, shouldGiveAnswerOf(10.000636, 5.000646) },
    
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