# dofry: Fry Estimation In geophys: Geophysics, Continuum Mechanics, Gravity Modeling

## Description

Calculate the Fry diagram for estimating shear on random point patterns

## Usage

 `1` ```dofry(x, y, PLOT = FALSE) ```

## Arguments

 `x` x-coordinates `y` y-coordinates `PLOT` logical, TRUE=plot

## Details

The number of points returned can be large and plotting can take a long time, so when plotting can restrict the points by using plotfry.

## Value

List:

 `X` x-coordinates `Y` y `mx` mean X `my` mean Y

## Author(s)

Jonathan M. Lees<jonathan.lees@unc.edu>

## 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.

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17``` ```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') ```