OP要求“最有效”,所以给定
geosphere
当您想在大量数据上使用它时非常慢
apply
本质上是一个循环函数,通常可以使用矢量化代码来击败
我提出了一个完全矢量化的解决方案,使用data.table
和library(geodist)
#dataframe need to be character arrays or the else the leading zeros will be dropped causing errors
df <- data.frame("ZIP_START" = c(95051, 94534, 60193, 94591, 94128, 94015, 94553, 10994, 95008),
"ZIP_END" = c(98053, 94128, 60666, 73344, 94128, 73344, 94128, "07105", 94128),
stringsAsFactors = FALSE)
library(zipcodeR)
library(data.table)
library(geodist)
## Convert the zip codes to data.table so we can join on them
## I'm using the centroid of the zipcodes (lng and lat).
## If you want the distance to the endge of the zipcode boundary you'll
## need to convert this into a spatial data set
dt_zips <- as.data.table( zip_code_db[, c("zipcode", "lng", "lat")])
## convert the input data.frame into a data.talbe
setDT( df )
## the postcodes need to be characters
df[
, `:=`(
ZIP_START = as.character( ZIP_START )
, ZIP_END = as.character( ZIP_END )
)
]
## Attach origin lon & lat using a join
df[
dt_zips
, on = .(ZIP_START = zipcode)
, `:=`(
lng_start = lng
, lat_start = lat
)
]
## Attach destination lon & lat using a join
df[
dt_zips
, on = .(ZIP_END = zipcode)
, `:=`(
lng_end = lng
, lat_end = lat
)
]
## calculate the distance
df[
, distance_metres := geodist::geodist_vec(
x1 = lng_start
, y1 = lat_start
, x2 = lng_end
, y2 = lat_end
, paired = TRUE
, measure = "haversine"
)
]
## et voila - note the missing zipcode 6066 and 73344
df
# ZIP_START ZIP_END lng_start lat_start lng_end lat_end distance_metres
# 1: 95051 98053 -121.98 37.35 -122.02 47.66 1147708.60
# 2: 94534 94128 -122.10 38.20 -122.38 37.62 69090.01
# 3: 60193 60666 -88.09 42.01 NA NA NA
# 4: 94591 73344 -122.20 38.12 NA NA NA
# 5: 94128 94128 -122.38 37.62 -122.38 37.62 0.00
# 6: 94015 73344 -122.48 37.68 NA NA NA
# 7: 94553 94128 -122.10 38.00 -122.38 37.62 48947.02
# 8: 10994 07105 -73.97 41.10 -74.15 40.72 44930.17
# 9: 95008 94128 -121.94 37.28 -122.38 37.62 54263.61
另请注意,返回的距离以米为单位。