dtDist2gc: Dist 2 gc

In SymbolixAU/spatial.data.table:

Description

Finds the distance of a point to a great-circle path

Usage

dtDist2gc(latFrom, lonFrom, latTo, lonTo, pointLat, pointLon,
  tolerance = 1e+09, r = earthsRadius())

Arguments

latFrom	latitude value for the start of the path
lonFrom	longitude value for the sttart of the path
latTo	lattitude value for the end of the path
lonTo	longitude value for the end of the path
pointLat	latitude value for the point
pointLon	longitude value for the point
r

Details

Sometimes called 'cross-track' distance

Value

distance in metres. The sign of the result indicates if the point is to the left (negative) or right (positive) of the line when traveling from 'latFrom,lonFrom' to 'latTo,lonTo'.

Examples

dt <- data.table(lat1 = c(0, 0),
                 lon1 = c(0, 0),
                 lat2 = c(20, -20),
                 lon2 = c(0, 0),
                 plat = c(10, -10),
                 plon = c(22, 22))

dt[, dist := dtDist2gc(lat1, lon1, lat2, lon2, plat, plon)]

SymbolixAU/spatial.data.table documentation built on May 9, 2019, 3:30 p.m.