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Reports until 15:24, Wednesday 01 July 2026
H1 CDS
erik.vonreis@LIGO.ORG - posted 15:24, Wednesday 01 July 2026 - last comment - 11:52, Thursday 02 July 2026(90862)
ndscope-test now has scatter plots

ndscope-test can now show "scatter" plots.

Plot one channel against others.  Each plot can have one channel giving the X value, and any number of channels giving Y values.  The plot will show one trace per Y value channel using the color of that channel.

Create a scatter plot from the command line by running "ndscope-test --scatter <x-channel> <y-channel-1> <y-channel-2> ..."

Create a scatter plot from a time domain plot.
1. Right click to get the pop up menu.
2. Select configure channels.
3. Select at least two of the channel names in the window with Control + click or Shift + click. The first selected channel is always the X channel
4. Press the Add Scatter Plot button at the bottom of the screen.
5. Press the OK button.


The timespan of the traces matches the time span of the traditional time-domain plots. Pan and zoom a time domain plot to 
change how much is shown on the scatter plot.

WARNING: This is a development release.  

There may be bugs.

Some bits are not working for scatter plots.  For example, the configure channels window does not appear for these plots.

Some needed interface is not yet included.  There's no way to change the X channel for a scatter plot yet, other than to 
open a new window and add the new X channel to the command line.  Scatter plots cannot be saved to or configured in yaml files.  Many more bits aren't done.

Comments related to this report
arnaud.pele@LIGO.ORG - 11:52, Thursday 02 July 2026 (90878)

Thank you Erik, this is going to be a useful feature for the CRS commissioning. 

I tested it with the following channels and confirmed that it works well (looking back in time when the CRS was online) : 

ndscope-test --scatter H1:ISI-HAM3_CRSRY_HOQI1_QUAD1_OUT_DQ H1:ISI-HAM3_CRSRY_HOQI1_QUAD2_OUT_DQ

The only feature request that I have is to set the X-Y to the same dimensions (or force the figure to be a square). In our application, we are evaluating how circular is the scatter plot, so having the X-Y different dimensions distorts the circle to an ellipse. For the same reasons, we would always set both axis limits to the same values, so having a way to do this quickly would be helpful.  

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