Thread Subject: How to make my graph smooth

I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.

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"Alex Jin" <limyijin@googlemail.com> wrote in message <ho7mh6$8r0$1@fred.mathworks.com>...
> I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.

instead of simply and tediously copy/paste-ing thousands of useless, meaningless data points, tell CSSM this:
which sequence of ML commands have YOU come up so far to solve YOUR particular problem...

us

"Alex Jin" <limyijin@googlemail.com> wrote in message <ho7mh6$8r0$1@fred.mathworks.com>...
> I have a graph. How can i make it smooth? The graph i have goes up and down while decreasing.. I would like to make it as smooth as possible.
>

As us points out, this is meaningless data, without
the understanding that comes along with it.

There are many tools to do smoothing in matlab and
on the file exchange. You might do something as
simpel as convolve it with a gaussian, to blur it. That
is a completely valid smoothing technique.

Or you might use smooth, or supersmoother, or lowess.

http://www.mathworks.com/matlabcentral/fileexchange/17986

http://www.mathworks.com/matlabcentral/fileexchange/22470

Or use the splines toolbox tools, or my own slm tools.

http://www.mathworks.com/matlabcentral/fileexchange/24443

Or you might use a Savitsky-Golay tool. There are several
of them on the FEX.

What really matters though, is what you know about this
curve. That will drive your result, as well as the method
you might use to do the smoothing.

The one thing I would suggest avoiding, is polyfit. Do NOT
use polyfit for this!

John

Hi Alex,

As an appendix to the rich set of smoothing options John has indicated: You could also use medfilt1 [or medfilt2 if your data is 2D].

Best.

"Sadik " <sadik.hava@gmail.com> wrote in message <ho7t3a$3ps$1@fred.mathworks.com>...
> Hi Alex,
>
> As an appendix to the rich set of smoothing options John has indicated: You could also use medfilt1 [or medfilt2 if your data is 2D].
>
> Best.

Good additions there. There are many tools to be found.
Knowing your problem, your data, and knowing what
are your goals for this are all important things before
you start.

A very important part of this is knowing the noise
structure in your data. If the noise can be assumed to
be random, uncorrelated, and normally distributed, then
you would use a different tool than if your noise has
other structure to it.

John