[R-SIG-Mac]Draw a curve, get a function?

[Peter Paul Sint]

At 11:05 Uhr +0200 13.06.2001, Richard D. Gill wrote:
>   
>I would like, in an elementary probability class, to draw by freehand
>a curve and import it into R as a function (e.g. as a bezier curve with
>knots). Does anyone know a quick and easy way to do this
>preferably using some freeware or cheap shareware drawing programme?
>The aim is to do it "live", quickly and easily.
>
>Yours
>Richard Gill.  gill@math.uu.nl       http://www.math.uu.nl/people/gill
>________

It may not be quite what you want but here my bit:
I used dataThief for similar things (translating scanned diagrams into tables).
You could follow a curve in any PICT-graph and catch coordinates pointwise (but not slopes). In R you would need a spline function or something similar.
My version (1.08) is from 1992 (and I have not tried it on my current 9.04).
I could forward it but you want to test it try first to find a more recent version.
http://www.nikhef.nl/~keeshu/datathief/
(there are links to similar Quictrace which may suit you better)
Commercial
http://www.curvuspro.ch/english/


-- 
Peter Sint
sint@oeaw.ac.at