Update [May 2019]: cyvincenty now uses multiple cores by default.

cyvincenty is a simple Cython implementation of Vincenty's inverse formula to find the distance between two latitude-longitude points. Rough testing shows that cyvincenty is 1000 to 2000 times faster than ArcPy 10.3 (cyvincenty calculates 1000 distances in .0016 seconds vs. ArcPy's 3.2 seconds).

This package contains two functions, vincenty and vincenty_cross.

vincenty finds the distance between two points:

from cyvincenty import vincenty

x1, y1 = -118, 32
x2, y2 = -117, 31

dist_km = vincenty(x1, y1, x2, y2)

vincenty_cross finds the all the distances between two sets of points (like scipy.spatial.distance.cdist).

import numpy as np
from cyvincenty import vincenty_cross

x1 = np.linspace(-118, -117, 100, dtype=np.float32)
y1 = np.linspace(32, 34, 100, dtype=np.float32)

x2 = np.linspace(-112, -110, 35, dtype=np.float32)
y2 = np.linspace(35, 37, 35, dtype=np.float32)

# A 100-by-35 numpy array
dist_km = vincenty_cross(x1, y1, x2, y2)

• Python 3 (tested with 3.6)
• Cython (tested with 0.27)
• NumPy (tested with 1.13)
• C compiler (tested with Visual Studio Community 2017)

Just clone the repository and run

$ python setup.py install

If you're using Windows, you will need to jump through the necessary hoops so Python can find your C compiler. Installing Visual Studio is the most straightforward route, but make sure you install the C/C++ command line interface (CLI) tools! If you're using Visual Studio, the easiest route is to run setup.py in a Visual Studio Developer console.