
Re: How to extract data points from a plot (can't use 'ginput')
Posted:
Aug 25, 2008 11:12 AM


"Forrest " <Remove.this@yahoo.com> wrote in message news:g8uhe3$go8$1@fred.mathworks.com... > "Steven Lord" <slord@mathworks.com> wrote in message > <g8ug33$u1$1@fred.mathworks.com>... >> >> "Forrest " <Remove.this@yahoo.com> wrote in message >> news:g8uf2j$j5s$1@fred.mathworks.com... >> > I'm using the 'psd' function to take the power spectral >> > density of a waveform. Afterwards I can view the plot > of >> > the psd, however, I can't seem to find the data that is >> > being plotted from the psd. I have the plot, but I > can't >> > find the x and y coordinates. I can't use ginput > because >> > there are 5000 data points. >> >> Get a handle to the line that PSD plotted using > FINDOBJ. Once you have that >> handle, GET the XData and YData properties. >> >>  >> Steve Lord >> slord@mathworks.com >> >> > Steve, > > I'm not very familiar with 'findobj'. Can you walk me > through how to do this.
The first example from DOC FINDOBJ should do it, as long as the line created by PSD is the only line on the current axes:
h = findobj(gca,'Type','line')
If it isn't, you'll need to specify another property that distinguishes the PSDcreated lines from the others. Take a look at the other documentation examples for ideas of some of the properties you can use for that purpose.
 Steve Lord slord@mathworks.com

