# gcMaxLat: Highest latitude on a great circle In geosphere: Spherical Trigonometry

## Description

What is northern most point that will be reached when following a great circle? Computed with Clairaut's formula. The southern most point is the antipode of the northern-most point. This does not seem to be very precise; and you could use optimization instead to find this point (see examples)

## Usage

 1 gcMaxLat(p1, p2)

## Arguments

 p1 longitude/latitude of point(s). Can be a vector of two numbers, a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialPoints* object p2 as above

## Value

A matrix with coordinates (longitude/latitude)

## Author(s)

Ed Williams, Chris Veness, Robert Hijmans

## Examples

 1 2 3 4 5 gcMaxLat(c(5,52), c(-120,37)) # Another way to get there: f <- function(lon){gcLat(c(5,52), c(-120,37), lon)} optimize(f, interval=c(-180, 180), maximum=TRUE)

### Example output

lon      lat
[1,] -49.82544 65.76869
\$maximum
[1] -49.82544

\$objective
[1] 65.76869

geosphere documentation built on May 26, 2019, 9:01 a.m.