distSeg {pgirmess} | R Documentation |
Computes the distances between the top coordinates of segments.
distSeg(mydata,decdeg=FALSE)
mydata |
A matrix or data frame of 4 columns giving the coordinates of each segment tops x1, y1, x2, y2 |
decdeg |
TRUE if point coordinates are longitude-latitude decimal degrees, in which case distances are measured in meters |
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:
A vector of distances
Patrick Giraudoux <pgiraudo@univ-fcomte.fr>
distNode
, distTot
, distShp
, distPolylines
x1<-rnorm(20) y1<-rnorm(20) x2<-rnorm(20) y2<-rnorm(20) mydata<-cbind(x1,y1,x2,y2) distSeg(mydata)