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I want to calculate the Euclidean distance between (2000) points scattered on an island and the shoreline. I have the points, a polygon of the island and also a polyline file of the coast in separate shapefiles. All files are georeferenced and all points are marked with x and y coordinates.

Is there a way to easily do this, preferably in a for loop so I get all the distances with a single code.

I already read that the package mapstat is useful, but I am somehow not able to install it.

Any tips will be welcome!

3

You could use gDistance from the rgeos package:

library("rgeos")
line <- readWKT("LINESTRING(1 0, 0.2 0, 0 0.2, 0 1)")
pt <- readWKT("GEOMETRYCOLLECTION(POINT(1.1 0.1), POINT(0.2 0.2), POINT(0.1 1))")

class(pt)
# [1] "SpatialPoints"
# attr(,"package")
# "sp"
class(line)
# [1] "SpatialLines"
# attr(,"package")
# [1] "sp"


plot(pt, axes=TRUE, xlim=c(-0.1, 1.2))
plot(line, add=TRUE)

plot

# distances between the two geometries in the units of the current projection;
# use planar coordinates for euclidean distances;
# byid=TRUE calculate distance for every point

gDistance(pt, line, byid=TRUE)
#        1      2   3
# 1 0.1414 0.1414 0.1
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