GeoDjango: Move a coordinate a fixed distance in a given direction (e.g. move a point east by one mile)

Question

Given a Point (django.contrib.gis.geos.Point) how do I find another point 1 mile east from that Point object?

(A) ---[ 1 mile ]---> (B)

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My failed attempts:

• I've considered trying to go hardcode the 1 mile east point but due to the curvature of the earth. The miles per degree change.

• Copius googling on SO and Geo Info Exchange. I assume I cannot find the terminology?

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• Python 3.6
• Django 1.11

Answer 1

You can accomplish this using the Geod class of pyproj.

from pyproj import Geod
geoid = Geod(ellps='WGS84')

def add_distance(lat, lng, az, dist):
    lng_new, lat_new, return_az = geoid.fwd(lon, lat, az, dist)
    return lat_new, lng_new

• lng: starting longitude
• lat: starting latitude
• az: azimuth, the direction of movement
• dist: distance in meters

So for your specific question, you could do the following:

from django.contrib.gis.geos import Point

def move_point_mile_east(point):
    dist = 1609.34
    lat, lng = add_distance(point.y, point.x, 90, dist)
    return Point(lng, lat)