choice filter

[asiripanich]

• spatial filter using nearest distance
  • https://rdrr.io/cran/nngeo/man/st_nn.html
  • https://github.com/jefferis/nabor
• group filter
• score filter

related to #80, #6

[asiripanich]

nabor is 100 times faster than nngeo.

library(nngeo)
#> Warning: package 'nngeo' was built under R version 3.6.2
#> Loading required package: sf
#> Warning: package 'sf' was built under R version 3.6.2
#> Linking to GEOS 3.7.2, GDAL 2.4.2, PROJ 5.2.0
library(nabor)
library(sf)

points <- towns

points_coords <- st_coordinates(points)
points_geo <- st_geometry(points)

rbenchmark::benchmark(
  nn_nngeo = st_nn(points_geo, points_geo, maxdist = 1000, k = c(20), progress = FALSE),
  nn_nabor = knn(data=points_coords, k=20, radius=1000)
)
#>       test replications elapsed relative user.self sys.self user.child
#> 2 nn_nabor          100   0.044    1.000     0.042    0.001          0
#> 1 nn_nngeo          100   4.436  100.818     4.344    0.062          0
#>   sys.child
#> 2         0
#> 1         0

^{Created on 2020-06-02 by the reprex package (v0.3.0)}