gcd.slc: Distance based on spherical law of cosines

In ejanalysis/proxistat: Create a Proximity Score in Each Census Unit, Based on Distances to Specified Points (as in EPA's EJScreen tool, for example)

Distance based on spherical law of cosines

Description

Calculates the geodesic distance between two points (or multiple pairs of points) specified by radian latitude/longitude.

Usage

gcd.slc(long1, lat1, long2, lat2)

Arguments

long1	longitude(s) in radians, vector of one or more numbers
lat1	latitude(s) in radians, vector of one or more numbers
long2	longitude(s) in radians, vector of one or more numbers
lat2	latitude(s) in radians, vector of one or more numbers

Details

long1 and lat1 must be same length. long2 and lat1 must be same length. All four must be the same length, defining pairs of points. Alternatively long1 and lat1 can define a single point while long2 and lat2 define a series of points, or vice versa. Taken from http://www.r-bloggers.com/great-circle-distance-calculations-in-r/ but use pmin instead of min to vectorize it to handle at least pairs.

Value

Distance in kilometers

See Also

convert, gcd, get.distances, get.distances.all

ejanalysis/proxistat documentation built on April 2, 2024, 10:13 a.m.