[R] persp( ) Question
Martin Maechler
maechler at stat.math.ethz.ch
Sat May 14 16:25:11 CEST 2005
>>>>> "DavidB" == Brahm, David <David.Brahm at geodecapital.com>
>>>>> on Fri, 6 May 2005 14:16:19 -0400 writes:
DavidB> Greg, Assign the output of "persp" to a variable
DavidB> "pmat":
R> pmat <- persp(X.grid, Y.grid, pred.loess1, theta=0,
R> phi=12)
DavidB> Now you can add points to your plot with the usual
DavidB> "points" command. But you have to translate your 3D
DavidB> coordinates (x,y,z) into 2D coordinates for "points"
DavidB> to understand, and that's what "trans3d" does:
R> points(trans3d(x,y,z, pmat), col="red")
DavidB> You supply the (x,y,z) values, of course. It's a
DavidB> mystery to me why "trans3d" is not included in the
DavidB> graphics package (where "persp" lives). HTH.
Yes, I had similar thoughts many weeks ago, and already then
prepared to add to trans3d(). Will do this now (for R 2.2.0).
Martin
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