calculate new coordinates based on Point, bearing and distance

[Jo]

Hi,

If I have a node, does JOSM have the possibility to calculate how to
move/displace it a given distance in meters in the direction of a given
compass bearing in degrees?

I tried a bit, based on formulas found on the internet. But the point is
always moved the same distance along the same bearing, somewhat to the
northeast, regardless of distance or bearing.


Polyglot


from math import asin, cos, sin, atan2, radians, degrees, pi

from javax.swing import JOptionPane
from org.openstreetmap.josm.gui import MainApplication

import org.openstreetmap.josm.command as Command

def displace2(coor, bearing, distance):
    _bearing = radians(float(bearing))
    _lat = radians(coor.lat())
    _lon = radians(coor.lon())
    earthRadiusInMetres = 6371000.0
    dist_over_ER =  float(distance) / earthRadiusInMetres
    cos_dist_over_ER = cos(dist_over_ER)
    sin_dist_over_ER = sin(dist_over_ER)
    lat2 = asin(sin(_lat) * cos_dist_over_ER + cos(_lat) * sin_dist_over_ER
* cos(_bearing))
    a = atan2(sin(_bearing) * sin_dist_over_ER * cos(_lat),
cos_dist_over_ER - sin(_lat) * sin(lat2))
    lon2 = (_lon + a + 3*pi) % (2*pi) - pi
    return degrees(lon2), degrees(lat2)

def displace(coor, bearing, distance):
    earth_radius = 6371000.0  # earth's radius in meter
    print bearing, distance
    _bearing = radians(bearing)
    print _bearing, cos(_bearing), sin(_bearing)
    lat1 = radians(coor.lat())
    lon1 = radians(coor.lon())
    distoverER = float(distance) / earth_radius
    cosdistoverER = cos(distoverER)
    sindistoverER = sin(distoverER)
    print distoverER, cosdistoverER, sindistoverER
    print sin(lat1) * cosdistoverER
    print cos(lat1) * sindistoverER * cos(_bearing)
    print sin(_bearing) * sindistoverER * cos(lat1)

    lat2 = asin(sin(lat1) * cosdistoverER +
                cos(lat1) * sindistoverER * cos(_bearing))

    print cosdistoverER - sin(lat1) * sin(lat2)
    print asin(sin(lat1) * cosdistoverER +
               cos(lat1) * sindistoverER * cos(_bearing))
    print atan2(sin(_bearing) * sindistoverER * cos(lat1),
                        cosdistoverER - sin(lat1) * sin(lat2))
    print lon1 + atan2(sin(_bearing) * sindistoverER * cos(lat1),
                        cosdistoverER - sin(lat1) * sin(lat2))

    lon2 = lon1 + atan2(sin(_bearing) * sindistoverER * cos(lat1),
                        cosdistoverER - sin(lat1) * sin(lat2))

    return degrees(lon2), degrees(lat2)

editLayer = MainApplication.getLayerManager().getEditLayer()
print '==== Fresh run ===='
if editLayer and editLayer.data:
    selected_nodes = editLayer.data.getSelectedNodes()
    print selected_nodes

    if not(selected_nodes):
        JOptionPane.showMessageDialog(MainApplication.parent, "Please
select node(s) to displace")
    else:
        for node in selected_nodes:
            b = int(node.get("bearing")) + 90
            if b > 360: b = b - 360
            print b
            lon, lat = displace2(coor = node.getCoor(),
                                 bearing=b,
                                 distance = 100.0)
            print node.getCoor().lon(), node.getCoor().lat()
            print lon, lat
            commandsList = []
            commandsList.append(Command.MoveCommand(node, lon, lat))
            MainApplication.undoRedo.add(Command.SequenceCommand(
                        "Move node", commandsList))