extract points over time

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muxav
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extract points over time

Postby muxav » Fri Feb 18, 2011 1:48 am

Hi there,
I wonder if anybody could help me with a very simple task, I just can't figure out. I have a set of transient data and want to show the development of a certain variable at specific points over time. Therefore I'd like to print the value of the variable to a file for each time step. I already tried to do this using the time series addon, which doesn't seem to work though.
Any help would be appreciated.

muxav

Ben

Re: extract points over time

Postby Ben » Fri Feb 18, 2011 12:55 pm

What about the time series add-on did not work?

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salter
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Re: extract points over time

Postby salter » Tue Feb 22, 2011 7:34 am

I've done this with a macro in the past, and even had the macro create a new zone of the data. It depends on what you want to do.

I too am curious what did not work with the addon.
Steve...

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muxav
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Re: extract points over time

Postby muxav » Thu Mar 03, 2011 2:24 am

Thanks for your replies,
I'll try to explain what is happening when I use the time series plugin.
Most likely I just don't know what it is supposed to do, but nevertheless i don't get usable results.
As described above, I have multiple result files, that form a transient data set. When I select "Probe to Create Time Seies Plot", a new frame is created showing an empty XY-Plot. When the mouse pointer is driven across the diagram, it is followed by a vertical line. Clicking into the diagram pops up the probe dialog, showing the value of the variable I'm interested in.
I wonder why I have to click to see the value at a specific time. I really can't find any option there to export a time series to a file. Maybe you can help me find it.
Regards,

muxav

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salter
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Re: extract points over time

Postby salter » Thu Mar 03, 2011 11:35 am

When you probe an X-Y plot, I assume you have a curve through the data that you are probing. In that case, only the data exists at specific solution times. If you want data between those times, that's where life gets tricky. In the probe function, probing at a location where no data but the line between points occurs, the probe function generally uses weighted averaging to obtain the data if the linear curve option is active (default). If you want something more smooth, you can change the curve type to a polynomial and then output the coefficients or equation that recreates the line. This does not necessarily prevent over or under shooting the data. You can also use an integration method of your own to interpolate the data. I typically use an Akima style spline because it is better behaved through data and produces the least over/under shoots between known data points. In that mode, you can write a macro that takes the known data points and generates the additional locations or specific locations between known data.

Basically, you either use a function built-in Tecplot to generate a continuous line, or implement one yourself with a macro.

Hope this helps.
Steve...



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Re: extract points over time

Postby gwf12 » Thu Mar 03, 2011 2:18 pm

Muxav,
It is possible that the add-on works just fine, but you are seeing an empty x-y plot because the Y-axis limits are not set right. The vertical line is because you are still in the probe mode; switch to "select" mode (selector tool), and select, then double-click the Y-axis, then in Range, reset limits to min/max values. When I use the add-on, min/max values are way off, so I have to reset them.

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Re: extract points over time

Postby muxav » Fri Mar 04, 2011 1:48 am

Thanks a lot guys!
The line was indeed outside the visible area. CTRL-F helped a lot here ;)
Changing the line type to akima spline then and exporting the data points is a perfectly working solution for me.

Regards,
muxav

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Re: extract points over time

Postby azysaeedi » Mon Nov 10, 2014 1:43 pm

salter wrote:When you probe an X-Y plot, I assume you have a curve through the data that you are probing. In that case, only the data exists at specific solution times. If you want data between those times, that's where life gets tricky. In the probe function, probing at a location where no data but the line between points occurs, the probe function generally uses weighted averaging to obtain the data if the linear curve option is active (default). If you want something more smooth, you can change the curve type to a polynomial and then output the coefficients or equation that recreates the line. This does not necessarily prevent over or under shooting the data. You can also use an integration method of your own to interpolate the data. I typically use an Akima style spline because it is better behaved through data and produces the least over/under shoots between known data points. In that mode, you can write a macro that takes the known data points and generates the additional locations or specific locations between known data.

Basically, you either use a function built-in Tecplot to generate a continuous line, or implement one yourself with a macro.

Hope this helps.


hello Salter,

Does these method also work for writing the charts which you could get from the probe solution over the time? I need data over the time by probe, but it only provide me with the figure, I couldnt have the specific numbers. I try .add but did not work for what i want
Thanks

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salter
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Re: extract points over time

Postby salter » Wed Nov 12, 2014 1:36 pm

Yes. If you generated a curve over time, you have the physical coordinates, other variables in your data set, and a time. Interpolating w.r.t. time will generate additional data between known points. All of the data can be extracted and put into a chart.
Steve...



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antonm5012
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Re: extract points over time

Postby antonm5012 » Mon Mar 20, 2017 7:22 am

I am having problem with this addon: time series data does not seem to get extracted when using "Probe to Create time Series Plot".

The "timeseries" plot shows only 1 point (correct though) corresponding to the first time-strand.

Has anyone encountered the same issue?
What could be the reason?

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Re: extract points over time

Postby sindyciaray » Mon Sep 18, 2017 5:42 am

The data points is is a perfectly working solution for me.


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