Source code for astromodels.utils.vincenty

import numpy as np

[docs] def vincenty(lon0, lat0, a1, s): """ Returns the coordinates of a new point that is a given angular distance s away from a starting point (lon0, lat0) at bearing (angle from north) a1), to within a given precision Note that this calculation is a simplified version of the full vincenty problem, which solves for the coordinates on the surface on an arbitrary ellipsoid. Here we only care about the surface of a sphere. Note: All parameters are assumed to be given in DEGREES :param lon0: float, longitude of starting point :param lat0: float, latitude of starting point :param a1: float, bearing to second point, i.e. angle between due north and line connecting 2 points :param s: float, angular distance between the two points :return: coordinates of second point in degrees """ lon0 = np.deg2rad(lon0) lat0 = np.deg2rad(lat0) a1 = np.deg2rad(a1) s = np.deg2rad(s) sina = np.cos(lat0) * np.sin(a1) num1 = np.sin(lat0) * np.cos(s) + np.cos(lat0) * np.sin(s) * np.cos(a1) den1 = np.sqrt( sina**2 + (np.sin(lat0) * np.sin(s) - np.cos(lat0) * np.cos(a1)) ** 2 ) lat = np.rad2deg(np.arctan2(num1, den1)) num2 = np.sin(s) * np.sin(a1) den2 = np.cos(lat0) * np.cos(s) - np.sin(lat0) * np.sin(s) * np.cos(a1) L = np.arctan2(num2, den2) lon = np.rad2deg(lon0 + L) return lon, lat