I have 2 lists (list1, list2) with latitude / longitudes of various locations. One list (list2) has locality names that list1
I add below a solution using the spatialrisk package. The key functions in this package are written in C++ (Rcpp), and are therefore very fast.
The function spatialrisk::points_in_circle() calculates the observations within radius from a center point. Note that distances are calculated using the Haversine formula. Since each element of the output is a data frame, purrr::map_dfr is used to row-bind them together:
ans <- purrr::map2_dfr(list1$longitude,
list1$latitude,
~spatialrisk::points_in_circle(list2, .x, .y,
lon = longitude,
lat = latitude,
radius = 2000000)[1,])
cbind(list1, ans)
longitude latitude longitude latitude locality distance_m
1 80.15998 12.90524 77.76180 13.02212 D 260484.0591
2 72.89125 19.08120 72.89537 19.07726 A 616.6369
3 77.65032 12.97238 77.64214 13.00954 C 4230.7216
4 77.60599 12.90927 77.58415 12.92079 D 2694.4566
5 72.88120 19.08225 72.89537 19.07726 A 1590.8723
6 76.65460 12.81447 76.65460 12.81447 E 0.0000
7 72.88232 19.08241 72.89537 19.07726 A 1487.8028
8 77.49186 13.00984 77.58415 12.92079 D 14089.1051
9 72.82228 18.99347 72.89537 19.07726 A 12089.6454
10 72.88871 19.07990 72.89537 19.07726 A 759.8012