Calculate distance from one point to all others

Question

I am working with a list of ID, X, and Y data for fire hydrant locations. I am trying to find the three closest fire hydrants for each fire hydrant in the list.

a =

Answer 1

If you have geolocation, we can perform simple distance calculation(https://en.m.wikipedia.org/wiki/Haversine_formula) to get kilometers distance between two locations. This code is NOT meant to be efficient. If this is what you want we can use numpy to speed it up:

import math

def distance(lat,lon, lat2,lon2):

    R = 6372.8  # Earth radius in kilometers

    # change lat and lon to radians to find diff

    rlat = math.radians(lat)
    rlat2 = math.radians(lat2)
    rlon = math.radians(lon)
    rlon2 = math.radians(lon2)

    dlat = math.radians(lat2 - lat)
    dlon = math.radians(lon2 - lon)


    m = math.sin(dlat/2)**2 + \
        math.cos(rlat)*math.cos(rlat2)*math.sin(dlon/2)**2

    return 2 * R * math.atan2(math.sqrt(m),
                               math.sqrt(1 - m))

a = [['ID1', 52.5170365, 13.3888599],
     ['ID2', 54.5890365, 12.5865499],
     ['ID3', 50.5170365, 10.3888599],
    ]

b = []  
for id, lat, lon in a:
    for id2, lat2, lon2 in a:
        if id != id2:
            d = distance(lat,lon,lat2,lon2)
            b.append([id,id2,d])

print(b)