Highlighting a region containing a scatter plot

Question

I have obtained the plot shown below using

ListLogLogPlot[Table[{Abs[a1[[i]]], Abs[a2[[i]]]}, {i, 400}]

I want to fill the whole region containing the scattered points as shown by the lines I have drawn by hand. Is it possible?

The appearance of the scattered points, themselves, is not mandatory in the plot.

I want to produce a similar kind of smooth plot like this.

You are much more likely to get help if you supplied the data that can be used to reproduce your plot. Also, unless you can describe how to generate the boundary line mathematically or in code, there is no answer. — m_goldberg, Mar 27 '19 at 12:41
I can share data file if you want. Can I give an error to each boundary points and plot it as a boundary line? — Not_Today, Mar 27 '19 at 13:07
You know the boundary points? Edit your question to include your method for determining them. — m_goldberg, Mar 27 '19 at 13:30
Well, that is the crux of the matter. There is no solution unless the boundary can be specified in a form that Mathematica understands.. — m_goldberg, Mar 27 '19 at 13:37
here 'a2' is a function of 'a1' other parameters. I have varied 'a1' from '10^-6' to '10' and plotted them against 'a2'. — Not_Today, Mar 27 '19 at 13:38
can I use other plot comments to get the filling region rathar than ListLogLogPlot. ? — Not_Today, Mar 27 '19 at 13:40
Is your problem filling in between the borders on your plot, or is it finding the borders? — Chris K, Mar 27 '19 at 13:53
Possible duplicate of DelaunayMesh in a specified closed region - creating a concave hull from a set of points — corey979, Mar 27 '19 at 14:08
filling the whole region that is scattered is the objective. so filling in between the borders might help — Not_Today, Mar 27 '19 at 14:21
@corey979 , nope that does hot help. I want it within the frame — Not_Today, Mar 27 '19 at 14:28
If there was any data to work with I might (a) replace each point by a small disk and (b) fiddle around with Dilation and Erosion until I got either a pleasing result or so frustrated I opened a bottle of scotch. — High Performance Mark, Mar 27 '19 at 15:21
Your added, vague, constraint requiring smoothness only makes your question harder to answer without precise specification of what is acceptable boundary curve. — m_goldberg, Mar 27 '19 at 15:22

score 1 · Answer 1 · answered Mar 27 '19 at 14:31

Given what you have said, the only thing I can think of is to use Mathematica's graphics drawing tools to draw the boundary freehand, extract the boundary points from the modified graphic, and convert it into a polygon. Here is an example.

Contrived data and plot for example.

SeedRandom[42]; data = RandomInteger[99, {100, 2}];
ListPlot[data, AspectRatio -> 1, PlotStyle -> AbsolutePointSize[5]]

I now use the drawing tools to draw a boundary around some points.

I then assign the marked plot to a variable.

Finally, I make a new plot with boundary line converted to a polygon.

markedPlot /. Line[pts___] -> {Blue, Opacity[.4], Polygon[pts]}

Thank you for ur effort. I have modified the question and added another image which might help you understand my problem. — Not_Today, Mar 27 '19 at 14:45

Highlighting a region containing a scatter plot

1 Answers1