| smooth_densify {smoothr} | R Documentation |
Densify lines or polygons
Description
This function adds additional vertices to lines or polygons via linear interpolation, always while keeping the original vertices. Each line segment will be split into equal length sub-segments. This densification algorithm treats all vertices as Euclidean points, i.e. new points will not fall on a great circle between existing vertices, rather they'll be along a straight line.
Usage
smooth_densify(x, wrap = FALSE, n = 10L, max_distance)
Arguments
x |
numeric matrix; matrix of coordinates. |
wrap |
logical; whether the coordinates should be wrapped at the ends, as for polygons and closed lines, to ensure a smooth edge. |
n |
integer; number of times to split each line segment. Ignored if
|
max_distance |
numeric; the maximum distance between vertices in the resulting matrix. This is the Euclidean distance and not the great circle distance. |
Details
This function works on matrices of points and is generally not called
directly. Instead, use smooth() with method = "densify" to apply this
smoothing algorithm to spatial features.
Value
A matrix with the coordinates of the densified curve.
Examples
# smooth_densify works on matrices of coordinates
# use the matrix of coordinates defining a line as an example
m <- jagged_lines$geometry[[2]][]
m_dense <- smooth_densify(m, n = 5)
class(m)
class(m_dense)
plot(m, type = "b", pch = 19, cex = 1.5, axes = FALSE, xlab = NA, ylab = NA)
points(m_dense, col = "red", pch = 19, cex = 0.5)
# max_distance can be used to ensure vertices are at most a given dist apart
m_md <- smooth_densify(m, max_distance = 0.05)
plot(m, type = "b", pch = 19, cex = 1.5, axes = FALSE, xlab = NA, ylab = NA)
points(m_md, col = "red", pch = 19, cex = 0.5)
# smooth is a wrapper for smooth_densify that works on spatial features
library(sf)
l <- jagged_lines$geometry[[2]]
l_dense <- smooth(l, method = "densify", n = 2)
class(l)
class(l_dense)
plot(l, lwd = 5)
plot(l_dense, col = "red", lwd = 2, lty = 2, add = TRUE)
plot(l_dense %>% st_cast("MULTIPOINT"), col = "red", pch = 19,
add = TRUE)