What R packages are available to calculate the minimum bounding box for a great circle?
For example:
box <- polycirc( c( longitude, latitude ), distance=35 )
This would return the bounding box for the circle with a radius of 35 kilo开发者_StackOverflow社区metres from the central point at the given coordinates (on Earth). Where:
box.longitude_min = The longitude of the circle's western-most point.
box.longitude_max = The longitude of the circle's eastern-most point.
box.latitude_min = The latitude of the circle's southern-most point.
box.latitude_max = The latitude of the circle's northern-most point.
Something like this should already exist in R, but I cannot find it. The closest I've found (from SO), which I am currently transmogrifying to R, is:
http://janmatuschek.de/LatitudeLongitudeBoundingCoordinates
Also, what is the word (if any) for minimum bounding rectangle of a circle? (The opposite of circumscribed.)
Given to me:
library( geosphere )
p <- c( longitude, latitude )
box <- apply( destPoint( p, c(0, 90, 180, 270), distance ), 2, range )
print( box )
Use the polycirc
function to generate the points of the circle and then min
and max
to found the bounding box :)
require(pgirmess)
circle <- polycirc(20, c(10, 20))
plot(circle, type = "l")
rect(min(circle[,1]), min(circle[,2]), max(circle[,1]), max(circle[,2]))
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