scatter plot with color defined by third column

SCairns · Post by **SCairns** » Tue Jul 10, 2012 4:49 am

I am looking for a way to plot data I have collected serially (in time) changing one parameter then repeating, such as measuring frequency response then changing temperature and measuring it again x N. I would like the data to be formatted based on the changed parameter, such as blue curves for -30°, green for 25° and red for 85°. The closest existing feature I have found is using the bubble plot, however I don’t see any way to specify the color for more than 2 parameters, my data may have a million points per curve, so changing the size of the bubble isn’t an option. Any thoughts?

Thanks

Post by **DPlotAdmin** » Tue Jul 10, 2012 9:15 am

A 3D scatter plot with both the azimuth and elevation angles set to 90.

A better solution would be for me to add more control to the colors on a bubble plot, though.

SCairns · Post by **SCairns** » Thu Jul 12, 2012 4:28 am

Yes, the Bubble plot allows me to have more than one Y axis, and of course more control on the colors would be good. I found the 3D scatter plot option shortly after I posted the above, however the Zparameter Min/Max control seemed odd. I have values of 1.2, 1.3 and 1.4. If I set the number of intervals for 2, with Min=1.2 and Max1.4 I get (results) of 1.3 and 1.4. If I set interval to 3, I get 1.267,1.33 and 1.4. Setting the interval to 3 but the lower limit at 1.1 gives me what I want, 1.2, 1.3 & 1.4. However I am having difficulty getting more than 2 colors. (2.3.2.9) Trial and error is made more difficult as each of the 3 curves has about 1.2 million points and my computer takes a while to respond to my changes. (Excel stopped partway through the first series and gave up.) The contour line seems to be working well here.

Post by **DPlotAdmin** » Thu Jul 12, 2012 11:10 am

I admit it is a bit confusing. The limits are the lower and upper bounds for each color. So if you use 3 intervals with the low/high set to 1.2-1.4, you'll get ranges of 1.2-1.26667,1.26667-1.3333,1.3333-1.4. I think what you probably want in your case is 3 intervals with low/high set to 1.15-1.45. That places the values you care about (1.2,1.3,1.4) in the middle of each band. The problem with that is the labels on the legend will be 1.15,1.25,1.35, and 1.45, which I'm sure is not what you want. I should probably add an option to label the middle of each band rather than the extremes.

maynarde · Post by **maynarde** » Thu Oct 09, 2014 1:03 pm

The issue is to have this a feature of the 2D scatter plot so a background image can be used. For example, plot lat/lon data with the color being velocity and using a picture from google earth as the background.

Post by **DPlotAdmin** » Thu Oct 09, 2014 6:09 pm

For 3D data the view is always 3D, even if you manipulate the view angles such that is appears as 2D.

You CAN do what you want, though, with latitude and velocity vs. longitude on a 2D plot, then use Options>Bubble Plot and select the velocity curve for the bubble magnitudes.