distNode: Computes the distances between each nodes of a polyline.
Description
Computes the distances between each nodes of a polyline.
Usage
distNode(pts,decdeg=FALSE)
Value
A vector of distances
Arguments
pts
A matrix or data.frame of the node coordinates column 1 = x,column 2 = y.
decdeg
TRUE if point coordinates are longitude-latitude decimal degrees, in which case distances are measured in meters
Details
If degdec is FALSE (default), distance computed is Euclidian. Units depends on the coordinate systems.
If decdeg = TRUE, D = 1852 * 60 * (180/pi) * acos ( sin(la1) * sin(la2) + cos(la1) * cos(la2) * cos(abs(lg1 - lg2)).
This method calculates the great circle distance, is based on spherical trigonometry, and assumes that: