maxEarthDist | R Documentation |
Maximum great-circle distance between points at lat-long coordinates. This is not computationally efficient. For large datasets, consider pages like https://stackoverflow.com/a/16870359.
maxEarthDist(
lat,
long,
data,
r = 6371,
fun = max,
each = TRUE,
quiet = FALSE,
...
)
lat, long, data |
Coordinates for |
r |
Earth Radius for |
fun |
Function to be applied. DEFAULT: |
each |
Logical: give max dist to all other points for each point separately?
If FALSE, will return the maximum of the complete distance matrix,
as if |
quiet |
Logical: suppress non-df warning in |
... |
Further arguments passed to fun, like na.rm=TRUE |
Single number
Berry Boessenkool, berry-b@gmx.de, Jan 2017
earthDist
d <- read.table(header=TRUE, text="
x y
14.9 53.73
1.12 53.12
6.55 58.13
7.71 71.44
")
plot(d, asp=1, pch=as.character(1:4), xlab="lon", ylab="lat")
for(i in 1:4) segments(d$x[-i], d$y[-i], d$x[i], d$y[i], col=2)
text(x=c(7,10,11), y=c(53,56,64), round(earthDist(y,x,d )[-1]), col=2)
text(x=c(4,4), y=c(56,61), round(earthDist(y,x,d,i=2)[3:4]), col=2)
text(x=7, y=64, round(earthDist(y,x,d,i=4)[3]), col=2)
round( earthDist(y,x,d, i=2) )
round( earthDist(y,x,d, i=3) )
round( maxEarthDist(y,x,d) )
round( maxEarthDist(y,x,d, each=FALSE) )
round( maxEarthDist(y,x,d, fun=min) )
maxEarthDist(y,x, d[1:2,] )
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