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Re: Plot scatter points with transparency [message #94581 is a reply to message #94580]

Sat, 15 July 2017 09:24

Nikola
Messages: 53
Registered: November 2009

Member

On Friday, July 14, 2017 at 11:00:31 PM UTC+1, ChengYu Xi wrote:
> Is there a way to do transparent scatter plots? (Usually I use cgScatter2D.pro to do scatter plots)
>
> I need to overlay a large number of scatter points in one plot, which consist of several groups. I want to assign different groups with different colors. The problems is they just tend to block each other due to the large number. Is a way to plot them with transparency or any other good solution?
>
> Thanks,
> Chengyu

A nice solution is to replace the central dense (all-black) cloud of points with a contour. An example is Fig.7 of
http://iopscience.iop.org/article/10.1086/590237/pdf

To make it, plot the contours of the 2D distribution/histogram, extract the data of the plotted contours using keywords path_xy = path_xy and /path_data_coords and then over-plot only those points that are out of the outermost contour line. I have a routine to do it, but I should prepare it a bit for sharing.

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[Message index]

		Plot scatter points with transparency By: chengyuxi34 on Fri, 14 July 2017 15:00
		Re: Plot scatter points with transparency By: Nikola on Sat, 15 July 2017 09:24
		Re: Plot scatter points with transparency By: Med Bennett on Sun, 16 July 2017 22:14
		Re: Plot scatter points with transparency By: Markus Schmassmann on Mon, 17 July 2017 03:56
		Re: Plot scatter points with transparency By: dg86 on Mon, 17 July 2017 18:56

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