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rgisr-sf

Filter polygons on coordinates

I'm currently working with a shapefile that does not contain explicit latitude and longitude coordinates. My goal is to filter out areas with latitudes above 60 degrees. I want to delete the small area in the lower right corner, but I don't have the latitude and longitude. Can anyone suggest a code to achieve this?

The shapefile look like this:

enter image description here

This is my current code:

shapefile_path <- "/Users/langbai/Desktop/lcsd000b16a_e/lcsd000b16a_e.shp"

shapefile_data <- st_read(shapefile_path)

convex_hulls_inset <- convex_hulls_with_farms %>%
  filter(lat < 60)

shapefile_inset <- shapefile_data %>%
  filter(st_coordinates(st_centroid(geometry))[, 2] < 80)
Solution

  • First, create a new column using mutate(), then filter() that column. Here's an example using the built-in nc dataset:

    library(sf)
library(dplyr)
library(ggplot2)

# Example data
nc <- st_read(system.file("shape/nc.shp", package = "sf"))

shapefile_inset <- nc %>%
  mutate(y = st_coordinates(st_centroid(geometry))[, 2]) %>%
  filter(y < 35) %>%
  select(-y)

ggplot() + 
  geom_sf(data = nc) +
  geom_sf(data = shapefile_inset, fill = "#DF536B")

    result