Translating JavaScript to Python

Javascript isn't too hard to understand.
Perhaps you can give us the javascript code.

Actually, I think mappersas should do the work.

Suggest: Look at the numeric and math package for python. With that plus the javascript code that I found with a quick google search: http://www.movable-type.co.uk/scripts/latlong.html#rhumb , you should be able to get the result very easily.

http://www.movable-type.co.uk/scripts/latlon.js

That is the js?

If you study the .rhumbDistanceTo method, that should give you an idea.
You can use the math module for sin, log, PI, etc

OK there are a couple of different functions I need, so here's the whole thing

# Given a start point and a distance d along constant bearing ?, this will calculate the destination point. If you maintain a constant bearing along a rhumb line, you will gradually spiral in towards one of the poles. # Latitude/longitude spherical geodesy formulae & scripts (c) Chris Veness 2002-2010 # http://www.movable-type.co.uk/scripts/latlong.html Def rhumbLine: # Returns the distance from this point to the supplied point, in km, travelling along a rhumb line * # see http://williams.best.vwh.net/avform.htm#Rhumb * # input tLatLon Latitude/longitude of destination point # returns Distance in km between this point and destination point LatLon.prototype.rhumbDistanceTo = function(point) var R = this._radius var lat1 = this._lat.toRad(), lat2 = point._lat.toRad() var dLat = (point._lat-this._lat).toRad(); var dLon = Math.abs(point._lon-this._lon).toRad(); var dPhi = Math.log(Math.tan(lat2/2+Math.PI/4)/Math.tan(lat1/2+Math.PI/4)); var q = (!isNaN(dLat/dPhi)) ? dLat/dPhi : Math.cos(lat1); # E-W line gives dPhi=0 # if dLon over 180° take shorter rhumb across 180° meridian: if (dLon > Math.PI) dLon = 2*Math.PI - dLon; var dist = Math.sqrt(dLat*dLat + q*q*dLon*dLon) * R; return dist.toPrecisionFixed(4);#// 4 sig figs reflects typical 0.3% accuracy of spherical model}/** #* Returns the bearing from this point to the supplied point along a rhumb line, in degrees * #* @param {LatLon} point: Latitude/longitude of destination point #* @returns {Number} Bearing in degrees from North */ LatLon.prototype.rhumbBearingTo = function(point) { var lat1 = this._lat.toRad(), lat2 = point._lat.toRad(); var dLon = (point._lon-this._lon).toRad(); var dPhi = Math.log(Math.tan(lat2/2+Math.PI/4)/Math.tan(lat1/2+Math.PI/4)); if (Math.abs(dLon) > Math.PI) dLon = dLon>0 ? -(2*Math.PI-dLon) : (2*Math.PI+dLon); var brng = Math.atan2(dLon, dPhi); return (brng.toDeg()+360) % 360;}/** * Returns the destination point from this point having travelled the given distance (in km) on the * given bearing along a rhumb line * @param {Number} brng: Bearing in degrees from North * @param {Number} dist: Distance in km * @returns {LatLon} Destination point LatLon.prototype.rhumbDestinationPoint = function(brng, dist) { var R = this._radius; var d = parseFloat(dist)/R; # d = angular distance covered on earth's surface var lat1 = this._lat.toRad(), lon1 = this._lon.toRad(); brng = brng.toRad(); var lat2 = lat1 + d*Math.cos(brng); var dLat = lat2-lat1; var dPhi = Math.log(Math.tan(lat2/2+Math.PI/4)/Math.tan(lat1/2+Math.PI/4)); var q = (!isNaN(dLat/dPhi)) ? dLat/dPhi : Math.cos(lat1); #E-W line gives dPhi=0 var dLon = d*Math.sin(brng)/q; check for some daft bugger going past the pole if (Math.abs(lat2) > Math.PI/2) lat2 = lat2>0 ? Math.PI-lat2 : -(Math.PI-lat2); lon2 = (lon1+dLon+3*Math.PI)%(2*Math.PI) - Math.PI; return new LatLon(lat2.toDeg(), lon2.toDeg());}

you guys are fast (& Im not because Im also trying to work)
yes http://www.movable-type.co.uk/scripts/latlon.js .
is where I am picking up the code.

is the rhumbDistanceTo method in the math module?

never mind the last question - figured out where the method is -
problem with trying to do 2 things at the same time

for the rhumbDistanceTo
this is basically what the javascript is doing

import math EARTHS_RADIUS = 6371 #Earth's mean radius in km def rhumb_distance(point1, point2, radius=EARTHS_RADIUS): R = radius lat1 = math.radians(point1[0]) #could also be point1.latitude lat2 = math.radians(point2[0]) #depends on if point1 is tuple or an object you define dLon = math.radians(abs(point2[1]-point1[1])) dLat = math.radians(poitn2[0]-point1[0]) dPhi = math.log(math.tan(lat2/2+math.pi/4)/math.tan(lat1/2+math.pi/4)) if dPhi: #make sure its nonzero q = dLat/dPhi else: q = math.cos(lat1) if dLon < math.pi: dLon = 2*math.pi - dLon dist = math.sqrt(dLat**2 + q**2*dLon*dLon) * R return dist

thank-you thank-you thank-you!

Use Js2Py ( https://github.com/PiotrDabkowski/Js2Py ). Translation from JavaScript to Python is fully automatic.