Re: 3d contour and surface plots from z,y and z data
- From: "Richard Willey" <rwilley@xxxxxxxxxxxxx>
- Date: Wed, 25 Mar 2009 09:21:11 -0400
As an alternative to using gridfit, you might want to take a look at Curve
Fitting Toolbox 2.0 which ships with the 9a release of MATLAB.
The toolbox has a new surface fitting Graphical User Interface which is
great for these types of problems.
Coincidentially, on Tuesday May 12th, I'm going to be delivering a webinar
titled Tip and Tricks: Data Analysis and Surface Fitting with MATLAB.
One of the main examples that we'll be working with is modeling Brake
Specific Fuel Consumption as a function of Engine Speed and Load.
We'll also be talking about the new surface fit objects that store the
results of this type of fitting operation.
Lets assume that I have three 200 x 1 vectors named BSFC, SPEED, and LOAD
I can create a fit object named Surface using the following command
Surface = fit( [SPEED, LOAD], BSFC, 'LOWESS', 'Span', .2 );
Once I create this fit object, I can operate it using a standard set of
methods.
For example, I can create a plot of the fit object as follows
plot(Surface)
Alternatively, I can create a residual vector as such
Residuals = BSFC - Surface(SPEED, LOAD);
"ilya holt" <ilya30@xxxxxxxxx> wrote in message
news:gqbi5e$9op$1@xxxxxxxxxxxxxxxxxxxxx
"John D'Errico" <woodchips@xxxxxxxxxxxxxxxx> wrote in message
<gqb4vh$a0i$1@xxxxxxxxxxxxxxxxxx>...
"ilya holt" <ilya30@xxxxxxxxx> wrote in message
<gqb3q1$ham$1@xxxxxxxxxxxxxxxxxx>...
i have some data collected from an ic engine, namely engine speed, bmep
and bsfc. i am required to create a contour plot of engine speed vs
bmep along the x and y axis respectively, and bsfc as height along the
z axis. im having great trouble getting the data into the correct
format, and then plotting it. from reading help files i understand i
need to make z into a matrix.. ? ive tried everything i could find but
haven't yet got anywhere with it.
i'm very new to matlab, can anyone tell me the steps i need to take to
do this?
Use gridfit. Find it on the file exchange.
http://www.mathworks.com/matlabcentral/fileexchange/8998
It will turn your scattered data into data on a
regular lattice of points. Then you can do
either a surf or a contour with no problems.
HTH,
John
Hi John, thanks for the reply.
can you tell me how to install this into matlab? i can't find instructions
anywhere as to how to make it work in the program
.
- References:
- 3d contour and surface plots from z,y and z data
- From: ilya holt
- Re: 3d contour and surface plots from z,y and z data
- From: John D'Errico
- Re: 3d contour and surface plots from z,y and z data
- From: ilya holt
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