Graduate Civil Engineering Student
2 vues (au cours des 30 derniers jours)
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I have a really trivial question, is it possible for MATLAB to trace a line or a curve and recreate its mathematical equation? We use very complicated old charts from the 1960s that have no data, and have to interpolate giving recurring errors and inconsistent results.
My question is basically this, is is possible to trace the curves via some computer program and have matlab convert it into an equation?
3 commentaires
Oleg Komarov
le 2 Mai 2011
Change the title of your thread to something related to question rather than leaving "Graduate Civil Engineering Student"
Réponses (5)
Walter Roberson
le 2 Mai 2011
There is the Curve Fitting Toolbox.
Generally speaking, if you do not have a good idea of what the form of the equation is, then you cannot determine the equation with any certainty: there are an infinite number of equations that fit any given set of data points perfectly. Indeed, if you get a perfect fit, chances are that you have over-fit.
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Kevin O'Hara
le 2 Mai 2011
MatLab has two function to create a curve through your data. [r1,m1,b1] = regression(xydata1(:,1)',xydata1(:,3)') and p1 = polyfit(xydata1(:,1)',xydata1(:,3)',2);
The coefficients m1 and b1 can be used for linear plots and the equation, whereas, p1 has the coefficients for a 2 or 3 or 4th order polynomial. I am using a 2nd order. See MatLab help function for more info on regression and ployfit functions.
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