geophys (version 1.4-1)

xtractlip: Extract Convex Hull Ellipse from fry

Description

Extract Convex Hull Ellipse from fry-diagram

Usage

xtractlip(AF)

Arguments

AF

x-y List out put of plotfry

Value

List: see output of ellipsoidhull: an object of class '"ellipsoid"', basically a 'list' with several components

Details

To get closest points to center, program cycles around in a circular manner pulling out the closest points. These points are used to estimate the chull ellipse.

References

Fry, N., (1979) <http://dx.doi.org/10.1016/0040-1951(79)90135-5> Random point distributions and strain measurement in rocks Tectonophysics, 60:89-105.

See Also

ellipsoidhull

Examples

# NOT RUN {
RDAT = randFRY(400, LIM=c(0,0, 200, 200) , rlen=5   )
length(RDAT$x)
plot(RDAT$x, RDAT$y, asp=1, pch=".", cex=2)
flag = sqrt( (RDAT$x-mean(RDAT$x))^2  + (RDAT$y-mean(RDAT$y))^2)<75

DAT = list(x=RDAT$x[flag], y=RDAT$y[flag])
 x = DAT$x
    y = DAT$y
 plot(x,y, asp=1, pch=21, col='red', bg='gold', ann=FALSE, axes=FALSE)

FF = dofry(DAT$x, DAT$y )
AF = plotfry(FF, dis=30)

Z = xtractlip(AF)

lines(cluster::predict.ellipsoid(Z$hull), col='red')  
   

# }