将lon / lat向量缩放为一定长度（以米为单位）

不确定我要哪种格式的输出，但这可能会让您入门...

产生两个新列；new_s和new_e，lon，lat-格式。

library( tidyverse )  
library( geosphere )

coords <- coords %>%
  #calculate bearing from center ppint to s-point
  mutate( bearing_c_to_s = pmap( list ( a = c_lon,
                                        b = c_lat,
                                        x = s_lon,
                                        y = s_lat ),
                                 ~ geosphere::bearing( c(..1, ..2), c(..3, ..4) ) 
                                 )
          ) %>%
  #calculate bearing from center ppint to s-point
  mutate( bearing_c_to_e = pmap( list ( a = c_lon,
                                        b = c_lat,
                                        x = e_lon,
                                        y = e_lat ),
                                 ~ geosphere::bearing( c(..1, ..2), c(..3, ..4) )  
                                 )
          ) %>%
  #calculate new point s coordinates, 25 meters from c using bearing c_to_s
  mutate( new_s = pmap( list ( a = c_lon,
                               b = c_lat,
                               x = bearing_c_to_s,
                               y = 25 ),
                        ~ geosphere::destPoint( c(..1, ..2), ..3, ..4 ) 
                        )
          ) %>%
  #calculate new point e coordinates, 25 meters from c using bearing c_to_e
  mutate( new_e = pmap( list ( a = c_lon,
                               b = c_lat,
                               x = bearing_c_to_e,
                               y = 25 ),
                        ~ geosphere::destPoint( c(..1, ..2), ..3, ..4 ) 
                        )
  )

在地图上输出

library( sf )
library( data.table )
setDT(coords)
coords_old <- data.table::melt(coords, measure.vars = patterns( lat = "^[a-z]_lat", lon = "^[a-z]_lon" ) )[, c("lon","lat")]
coords_old <- sf::st_as_sf( coords_old, coords = c("lon", "lat"), crs = 4326 )
coords[, c("new_s_lon", "new_s_lat") := ( as.list( unlist( new_s ) ) ) ]
coords[, c("new_e_lon", "new_e_lat") := ( as.list( unlist( new_e ) ) ) ]
coords_new <- data.table::melt(coords, measure.vars = patterns( lat = "^(c|new_[se])_lat", lon = "^(c|new_[se])_lon" ) )[, c("lon","lat")]
coords_new <- sf::st_as_sf( coords_new, coords = c("lon", "lat"), crs = 4326 )

library( leaflet )
leaflet() %>% 
  addTiles() %>% 
  addCircleMarkers( data = coords_old, color = "red" ) %>%
  addCircleMarkers( data = coords_new, color = "blue" )

旧点是红色，新点是蓝色..中心点保持不变..