Pandas数据帧中的每一行包含2个点的lat/lng坐标.使用下面的Python代码,计算许多(数百万)行的这两个点之间的距离需要很长时间!
考虑到2点相距不到50英里并且准确性不是很重要,是否可以更快地进行计算？
from math import radians, cos, sin, asin, sqrt
def haversine(lon1, lat1, lon2, lat2):
"""
Calculate the great circle distance between two points
on the earth (specified in decimal degrees)
"""
# convert decimal degrees to radians
lon1, lat1, lon2, lat2 = map(radians, [lon1, lat1, lon2, lat2])
# haversine formula
dlon = lon2 - lon1
dlat = lat2 - lat1
a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
c = 2 * asin(sqrt(a))
km = 6367 * c …我有一个.csv文件,其中包含以下格式的城市,纬度和经度数据:
CITY|LATITUDE|LONGITUDE
A|40.745392|-73.978364
B|42.562786|-114.460503
C|37.227928|-77.401924
D|41.245708|-75.881241
E|41.308273|-72.927887
我需要以下面的格式创建一个距离矩阵(请忽略虚拟值):
A B C D E
A 0.000000 6.000000 5.744563 6.082763 5.656854
B 6.000000 0.000000 6.082763 5.385165 5.477226
C 1.744563 6.082763 0.000000 6.000000 5.385165
D 6.082763 5.385165 6.000000 0.000000 5.385165
E 5.656854 5.477226 5.385165 5.385165 0.000000
我已将数据加载到pandas数据框中,并创建了一个交叉连接,如下所示:
import pandas as pd
df_A = pd.read_csv('lat_lon.csv', delimiter='|', encoding="utf-8-sig")
df_B = df_A
df_A['key'] = 1
df_B['key'] = 1
df_C = pd.merge(df_A, df_B, on='key')