Dear mailing list,
I have following array:
X2 Y2
[1,] 422.7900 6.0
[2,] 469.8007 10.5
[3,] 483.9428 11.0
[4,] 532.4917 25.5
[5,] 596.1942 33.5
[6,] 630.8496 40.5
[7,] 733.2996 45.0
[8,] 946.4779 32.0
[9,] 996.8068 35.5
[10,] 1074.3310 23.0
I do afterwards the following:
plot.new()
plot.window(xlim=c(min(X1)-50,max(X1)+50),
ylim=c(min(Y1)-25,max(Y1)+25))
axis(2, cex.axis=1.2)
axis(1, cex.axis=1.2)
points(X2, Y2, type="p", pch=0, cex=1.2, col="black")
title(main="Dyke Geometry Along Strike", cex.main=1.2, font.main=4)
title(xlab="distance [m]", cex.lab=1.2)
title(ylab="half-thickness [m]", cex.lab=1.2)
box()
I would like curve fitting where I proceeded with a non
linear-regression with the according function below:
nls(formula = Y2 ~ abs(b*abs(1-X2^2/a^2)^(1/2)), start = list( a=282,
b=40))
The formula should give the y-positive part of an ellipse in my opinion
or I might be completely wrong.
In the end I would like to fit a curve of half an ellipse through the
data. I might could do this as well with a 2nd order polynomial fit. I
am grateful for any suggestions and comments to my problem.
Cheers
--
Niklaus Hürlimann
Doctorant-PhD
Université de Lausanne
Institut de Minéralogie et Géochimie
L'Anthropole
CH-1015 Lausanne
Suisse
E-mail: [email protected]
Tel:+41(0)21 692 4452
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