McSpatial (version 1.1.1)

geodistance: Calculates distances using the great circle formula

Description

geodistance calculates distances in miles between a set of observations and a location. Distances are calculated in miles using the great circle formula. Geographic coordinates must be expressed in latitudes and longitudes.

Usage

geodistance(longvar, latvar, lotarget, latarget, dcoor = TRUE)

Arguments

longvar

Longitude variable, in degrees.

latvar

Latitude variable, in degrees.

lotarget

Target longitude.

latarget

Target latitude.

dcoor

If dcoor = T, also calculates the distance east (deast) and north (dnorth) of the target point.

Value

• dist
  A vector with the distance in miles between each data point and the target point.
• dnorth
  A vector with the number of miles north of the target point for each data point. dnorth < 0 for observations that are south of the target point.
• deast
  A vector with the number of miles east of the target point for each data point. deast < 0 for observations that are west of the target point.

See Also

geodensity geoshape

Examples

data(cookdata)
dmat <- geodistance(longvar=cookdata$LONGITUDE ,latvar=cookdata$LATITUDE,  lotarget=-87.627800, 
	latarget=41.881998)
cookdata$dcbd <- dmat$dist
cookdata$dnorth <- dmat$dnorth
cookdata$deast <- dmat$deast