geophys (version 1.2-1)

TriangleInfo: Triangle Information

Description

Given a triangle (three non-colinear points, return info that is useful

Usage

TriangleInfo(P1, P2 = c(0, 1), P3 = c(1, 0), add = FALSE)

Arguments

P1

vector or list(x,y) of 2D point 1

P2

vector or list(x,y) of 2D point 2

P3

vector or list(x,y) of 2D point 3

add

logical, if TRUE add a variety of lines to the plot

Value

• list
• BI
  x,y location of center of inscribed circle
• CIRCUM
  x,y location of center of circumscribed circle
• IH
  x,y location of Intersection of bisectors
• CEN
  centroid location
• r
  radius of inscribed circle
• R
  radius of circumscribed circle
• AngBis
  loci of vectors bisecting each corner on opposite leg
• H
  lengths of altitudes
• M
  lengthsof medians
• TEE
  lengths of perpendiculars
• Area
  Area of triangle

Details

If either P1 P2 or P3 are an x,y list, they are converted to vectors. If P2 and P3 are missing, P1 contains all the points. Input can be list of 3 x,y values, a 3 by 2 matrix .

References

http://en.wikipedia.org/wiki/Triangle_center

http://en.wikipedia.org/wiki/Encyclopedia_of_Triangle_Centers

See Also

Intersect2points, Sect2vex, AXB.prod, TriangleCenter, rot2Zplane

Examples

P1 = runif(2)
P2 = runif(2)
P3 = runif(2)

  

theX = c(P1[1],P2[1], P3[1])
theY = c(P1[2],P2[2], P3[2])


        plot(theX , theY, asp=1)
        
        
        points(theX , theY)
        text(theX , theY, labels=1:3, pos=3)
        lines(c(theX, theX[1]), c(theY, theY[1]) )

TriangleInfo(P1, P2, P3, add=TRUE)
#####    TriangleInfo(rbind(P1, P2, P3),   add=TRUE)