Calculate the azimuth between pairs of points
Calculates the (planar!) azimuth between pairs in two sequences of points x and y. When point sequence length doesn't match, the shorter one is recycled.
st_azimuth(x, y)
x |
Object of class |
y |
Object of class |
A numeric vector, of the same length as (the longer of) x and y, with the azimuth values from x to y (in decimal degrees, ranging between 0 and 360 clockwise from north). For identical points, an azimuth of NA is returned.
The function currently calculates planar azimuth, ignoring CRS information. For bearing on a sphere, given points in lon-lat, see function geosphere::bearing.
# Two points x = st_point(c(0, 0)) y = st_point(c(1, 1)) st_azimuth(x, y) # Center and all other points on a 5*5 grid library(stars) m = matrix(1, ncol = 5, nrow = 5) m[(nrow(m)+1)/2, (ncol(m)+1)/2] = 0 s = st_as_stars(m) s = st_set_dimensions(s, 2, offset = ncol(m), delta = -1) names(s) = "value" pnt = st_as_sf(s, as_points = TRUE) ctr = pnt[pnt$value == 0, ] az = st_azimuth(ctr, pnt) plot(st_geometry(pnt), col = NA) plot(st_connect(ctr, pnt, k = nrow(pnt), progress = FALSE), col = "grey", add = TRUE) plot(st_geometry(pnt), col = "grey", add = TRUE) text(st_coordinates(pnt), as.character(round(az)), col = "red")
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