OSRM areas

Installation

# install.packages('remotes')
# remotes::install_github('d2cml-ai/osrmareas')

Usage

library(osrmareas)
library(ggplot2)
library(dplyr)

The osrmareas package provides functions for working with OSRM routes and generating area polygons. Here’s an example of how to use the package:

lat <- -9.0686007
lon <- -78.5891182

# Get routes inside a specified radius
routes <- get_routes_inside(lat, lon, radius_km = 2, grid_size = 0.300)

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routes

Simple feature collection with 49 features and 6 fields
Geometry type: LINESTRING
Dimension:     XY
Bounding box:  xmin: -78.60491 ymin: -9.08677 xmax: -78.57216 ymax: -9.04581
Geodetic CRS:  WGS 84
First 10 features:
             duration distance         x         y
src_dst...1  4.546667   2.6409 -78.60481 -9.084138
src_dst...2  4.078333   2.1288 -78.59959 -9.084138
src_dst...3  3.378333   1.7461 -78.59437 -9.084138
src_dst...4  3.096667   1.8123 -78.58915 -9.084138
src_dst...5  4.255000   2.3772 -78.58393 -9.084138
src_dst...6  4.213333   2.7717 -78.57871 -9.084138
src_dst...7  5.561667   3.7278 -78.57349 -9.084138
src_dst...8  4.618333   2.6891 -78.60481 -9.078958
src_dst...9  4.155000   2.3272 -78.59959 -9.078958
src_dst...10 3.891667   2.0509 -78.59437 -9.078958
                                   geometry  x_origin  y_origin
src_dst...1  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...2  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...3  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...4  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...5  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...6  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...7  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...8  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...9  LINESTRING (-78.58915 -9.06... -78.58912 -9.068601
src_dst...10 LINESTRING (-78.58915 -9.06... -78.58912 -9.068601

The get_routes_inside function retrieves routes within a given radius from a specified latitude and longitude. It returns a dataframe with the routes information.

# Plot the routes on a map
p1 <- 
  ggplot(routes) + 
  geom_sf() + 
  coord_sf() +
  theme_minimal()
p1

You can visualize the routes using ggplot2 and the geom_sf function.

Filter points inside 2km radius:

km_max <- 2
routes_km <- routes |> 
  dplyr::filter(distance < km_max) 

p2 <- 
  routes_km |> 
  ggplot() +
  geom_sf() +
  theme_minimal()
p2

This code filters the routes within a maximum distance of 2km and plots them on a map.

Generate a polygon shapefile:

area1 <- 
  get_area(routes_km, km_max, concavity = 1) 
area2 <- 
  get_area(routes_km, km_max, concavity = 2)

area1 |> 
  ggplot() +
  geom_sf()

area2 |> 
  ggplot() +
  geom_sf()

The get_area function generates a polygon shapefile based on the filtered routes within a specified maximum distance and concavity level.

Routes inside the area:

bind_rows(area1, area2) |> 
  mutate(concavity = row_number() |> factor()) |> 
  ggplot() +
  geom_sf(aes(color = concavity), fill = NA) +
  geom_sf(data = routes_km, color = "grey80") +
  geom_point(aes(lon, lat)) +
  labs(title = "Area between 2km (car)") +
  theme_minimal() 

This code plots the generated area polygons along with the filtered routes inside the area. The concavity level is used to differentiate the polygons, and the original routes are shown in grey.

Please note that you need to have the necessary packages installed and loaded (osrmareas, ggplot2, dplyr) in order to run the code successfully.