I am working with the R programming language.
I am interested in learning about how to calculate the driving distance (e.g. based on road networks) between two sets of coordinates.
For example:
- CN Tower: 290 Bremner Blvd, Toronto, ON M5V 3L9 (-79.61203, 43.68312)
- Toronto Airport: 6301 Silver Dart Dr, Mississauga, ON L5P 1B2 (-79.61203, 43.64256)
To solve this problem, I tried to download the shapefile for the Canadian Road Network and subset it for the Province of Ontario:
library(sf)
library(rgdal)
library(sfnetworks)
# Set the URL for the shapefile
url <- "https://www12.statcan.gc.ca/census-recensement/2011/geo/RNF-FRR/files-fichiers/lrnf000r22a_e.zip"
# Create a temporary folder to download and extract the shapefile
temp_dir <- tempdir()
temp_file <- file.path(temp_dir, "lrnf000r22a_e.zip")
# Download the shapefile to the temporary folder
download.file(url, temp_file)
# Extract the shapefile from the downloaded zip file
unzip(temp_file, exdir = temp_dir)
# Read the shapefile using the rgdal package
a = st_read(file.path(temp_dir, "lrnf000r22a_e.shp"), query="select * from lrnf000r22a_e where PRUID_R ='35'")
When imported into R, the file looks something like this:
Simple feature collection with 570706 features and 21 fields
Geometry type: LINESTRING
Dimension: XY
Bounding box: xmin: 5963148 ymin: 665490.8 xmax: 7581671 ymax: 2212179
Projected CRS: NAD83 / Statistics Canada Lambert
First 10 features:
OBJECTID NGD_UID NAME TYPE DIR AFL_VAL ATL_VAL AFR_VAL ATR_VAL CSDUID_L CSDNAME_L CSDTYPE_L CSDUID_R CSDNAME_R CSDTYPE_R PRUID_L PRNAME_L PRUID_R PRNAME_R RANK
1 4 3434819 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 3526003 Fort Erie T 3526003 Fort Erie T 35 Ontario 35 Ontario 5
2 5 1358252 South LINE <NA> <NA> <NA> <NA> <NA> 3551027 Gordon/Barrie Island MU 3551027 Gordon/Barrie Island MU 35 Ontario 35 Ontario 5
3 8 1778927 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 3512054 Wollaston TP 3512054 Wollaston TP 35 Ontario 35 Ontario 5
4 11 731932 Albion RD <NA> <NA> <NA> 2010 2010 3520005 Toronto C 3520005 Toronto C 35 Ontario 35 Ontario 3
5 18 3123617 County 41 RD <NA> 640 708 635 709 3511015 Greater Napanee T 3511015 Greater Napanee T 35 Ontario 35 Ontario 3
6 20 4814160 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 3553005 Greater Sudbury / Grand Sudbury CV 3553005 Greater Sudbury / Grand Sudbury CV 35 Ontario 35 Ontario 5
7 21 1817031 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 3537028 Amherstburg T 3537028 Amherstburg T 35 Ontario 35 Ontario 5
8 24 4825761 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 3554094 Timiskaming, Unorganized, West Part NO 3554094 Timiskaming, Unorganized, West Part NO 35 Ontario 35 Ontario 5
9 25 544891 Dunelm DR <NA> 1 9 2 10 3526053 St. Catharines CY 3526053 St. Catharines CY 35 Ontario 35 Ontario 5
10 28 1835384 Seven Oaks DR <NA> 730 974 731 975 3515005 Otonabee-South Monaghan TP 3515005 Otonabee-South Monaghan TP 35 Ontario 35 Ontario 5
CLASS _ogr_geometry_
1 23 LINESTRING (7269806 859183,...
2 23 LINESTRING (6921247 1133452...
3 23 LINESTRING (7320857 1089403..
Then, by consulting different references (e.g. 1. The sfnetwork data structure) - I tried to calculate the distance between these two points:
# convert the shapefile to an sfnetwork object
net <- as_sfnetwork(a)
# define your start and end points
q1 <- st_point(c(-79.61203, 43.68312))
q2 <- st_point(c(-79.38709, 43.64256))
# set the CRS of the points to match the CRS of your shapefile
q1 <- st_sfc(q1, crs = st_crs(a))
q2 <- st_sfc(q2, crs = st_crs(a))
# find the shortest path between the two points
path <- st_network_paths(net, q1, q2)
# calculate the distance of the path in meters
distance <- sum(st_length(path))
But I get the following error: Error in UseMethod("st_geometry") : no applicable method for 'st_geometry' applied to an object of class "c('tbl_df', 'tbl', 'data.frame')"
Can someone please show me how to fix this problem?
Thanks!