Fixed #18

DESCRIPTION

@@ -22,6 +22,7 @@ Depends:
 Imports: 
     dplyr (>= 0.7.4),
     leaflet (>= 1.1.0),
+    lwgeom (>= 0.1-4),
     magrittr (>= 1.5),
     miniUI (>= 0.1.1),
     purrr (>= 0.2.4),

NAMESPACE

@@ -15,6 +15,7 @@ import(miniUI)
 import(rlang)
 import(sf)
 import(shiny)
+importFrom(dplyr,arrange)
 importFrom(dplyr,everything)
 importFrom(dplyr,filter)
 importFrom(dplyr,if_else)
@@ -23,6 +24,7 @@ importFrom(dplyr,matches)
 importFrom(dplyr,mutate)
 importFrom(dplyr,right_join)
 importFrom(dplyr,select)
+importFrom(dplyr,slice)
 importFrom(jpmesh,coords_to_mesh)
 importFrom(jpmesh,fine_separate)
 importFrom(jpmesh,mesh_to_coords)
@@ -31,12 +33,12 @@ importFrom(magrittr,extract)
 importFrom(magrittr,use_series)
 importFrom(purrr,map)
 importFrom(purrr,pmap)
+importFrom(purrr,pmap_dbl)
 importFrom(purrr,reduce)
 importFrom(purrr,set_names)
 importFrom(sf,st_buffer)
 importFrom(sf,st_contains)
 importFrom(sf,st_intersects)
-importFrom(sf,st_is)
 importFrom(sf,st_point)
 importFrom(sf,st_read)
 importFrom(sf,st_sf)

R/find_city.R

@@ -1,9 +1,9 @@
 #' Detect prefecture by coordinates
 #'
 #' @inheritParams find_city
-#' @importFrom dplyr mutate select right_join
-#' @importFrom purrr set_names
-#' @importFrom sf st_is st_point
+#' @importFrom dplyr arrange mutate select slice right_join
+#' @importFrom purrr pmap_dbl set_names
+#' @import sf
 #' @note The `find_pref` function was added in version 0.3.0
 #' @examples
 #' \dontrun{
@@ -15,7 +15,7 @@
 #' }
 #' @export
 find_pref <- function(longitude, latitude, geometry = NULL, ...) {
-  pref_code <- prefecture <- city_code <- NULL
+  . <- pref_code <- prefecture <- city_code <- dist <- NULL
 
   if (!is.null(geometry)) {
     if (sf::st_is(geometry, "POINT")) {
@@ -28,6 +28,23 @@ find_pref <- function(longitude, latitude, geometry = NULL, ...) {
 
   res <- find_city(longitude, latitude, ...)
   if (!is.null(res)) {
+    if (nrow(res) > 1) {
+      res <-
+        res %>%
+        dplyr::mutate(dist = purrr::pmap_dbl(
+          ., ~
+            sf::st_distance(sf::st_centroid(..4) %>%
+                              sf::st_sfc(crs = 4326),
+                                             sf::st_point(c(longitude, latitude)) %>%
+                                               sf::st_sfc(crs = 4326), by_element = TRUE)))
+
+      res <-
+        res %>%
+        dplyr::arrange(dist) %>%
+        dplyr::slice(1L) %>%
+        dplyr::select(-dist)
+    }
+
     df_tmp <- res %>%
       dplyr::mutate(pref_code = substr(city_code, 1, 2)) %>%
       dplyr::select(pref_code, prefecture)

tests/testthat/test-find_city.R

@@ -19,6 +19,12 @@ test_that("prefecture", {
   expect_equal(test$pref_code, "24")
   test <- find_prefs(geometry = sf::st_point(c(136.6833, 35.05)))
   expect_equal(dim(test), c(6, 4))
+
+  skip_if_not_installed("lwgeom")
+  test <-
+    find_pref(135.8167, 35.3)
+  expect_equal(dim(test), c(1, 3))
+
 })
 
 test_that("Failed", {