Skip to main content

plotting - Extracting the coordinate of a particular point of interest from a ListPlot


Is there a way to obtain the coordinate of a point of interest in a ListPlot?


As an example, I have a list containing many sets of 2D coordinates and the plot drawn is discontinuous at one point (the first derivative is not continuous and the gradient increases suddenly).


Can I extract the location of that point interactively? Otherwise, I have to search through the list of data myself to determine the change of gradient, which defeats the whole purpose of drawing a plot. Also, using the Get Coordinates function from the right click menu does not give very accurate results.



Answer



ListPlot accepts data wrappers besides Tooltip


(although I could not find any mention of this feature in the docs).


So, @Jens' method can be achieved without post-processing:


 data = Table[{Sin[n], Sin[2 n]}, {n, 50}];
 ListPlot[PopupWindow[Tooltip[#], #] & /@ data]


enter image description here


On mouseover:


enter image description here


Click on a point:


enter image description here


Note: Thought this was a new feature added in Version-9, but as @Alexey Popkov noted it also works in version 8.0.4, so it has been around for some time.


Update: A simpler version of @Mr.Wizard's printTip can also be used as a wrapper directly inside ListPlot:


 ListPlot[Button[Tooltip@#, Print[#]] & /@ N@data]


enter image description here


Update 2: Collecting point coordinates:


 clicks = {};
 Column[{ListPlot[Button[Tooltip@#, AppendTo[clicks, #]] & /@ N@data,
   ImageSize -> 300],
  "\n\t", Row[{"clicks = " , Dynamic[clicks // TableForm]}]}]

enter image description here


Comments

Post a Comment

Popular posts from this blog

plotting - How to draw lines between specified dots on ListPlot?

I would like to create a plot where I have unconnected dots and some connected. So far, I have figured out how to draw the dots. My code is the following: ListPlot[{{1, 1}, {2, 2}, {3, 3}, {4, 4}, {1, 4}, {2, 5}, {3, 6}, {4, 7}, {1, 7}, {2, 8}, {3, 9}, {4, 10}, {1, 10}, {2, 11}, {3, 12}, {4,13}, {2.5, 7}}, Ticks -> {{1, 2, 3, 4}, None}, AxesStyle -> Thin, TicksStyle -> Directive[Black, Bold, 12], Mesh -> Full] I have thought using ListLinePlot command, but I don't know how to specify to the command to draw only selected lines between the dots. Do have any suggestions/hints on how to do that? Thank you. Answer One possibility would be to use Epilog with Line : ListPlot[ {{1, 1}, {2, 2}, {3, 3}, {4, 4}, {1, 4}, {2, 5}, {3, 6}, {4, 7}, {1, 7}, {2, 8}, {3, 9}, {4, 10}, {1, 10}, {2, 11}, {3, 12}, {4, 13}, {2.5, 7}}, Ticks -> {{1, 2, 3, 4}, None}, AxesStyle -> Thin, TicksStyle -> Directive[Black, Bold, 12], Mesh -> Full, Epilog -> { Line[ ...
Post a Comment
Read more

equation solving - Invert and fit implicitly defined curve

I need to fit an implicitly defined curve. I thought I could get some data out of Solve , and then using FindFit . Therefore, I would like to find the relation the parametric curve defined by $F(x,y)=0$: Solve[-(1/2) + 1/2 (0.41202 BesselK[0, 0.1 Sqrt[x^2 + y^2]] + (0.101483 x BesselK[1, 0.1 Sqrt[x^2 + y^2]])/Sqrt[x^2 + y^2]) == 0, y] But I can't get an output: Solve was unable to solve the system with inexact coefficients or the system obtained by direct rationalization of inexact numbers present in the system. Since many of the methods used by Solve require exact input, providing Solve with an exact version of the system may help. >> Edit: In particular, I would like to fit the data coming from the curve with the expression of another curve, and not with a function $f(x)$. In particular, since this clearly looks like a cardioid , I would like it to fit to something like it. What other strategies could I try?
Post a Comment
Read more

dynamic - How can I make a clickable ArrayPlot that returns input?

I would like to create a dynamic ArrayPlot so that the rectangles, when clicked, provide the input. Can I use ArrayPlot for this? Or is there something else I should have to use? Answer ArrayPlot is much more than just a simple array like Grid : it represents a ranged 2D dataset, and its visualization can be finetuned by options like DataReversed and DataRange . These features make it quite complicated to reproduce the same layout and order with Grid . Here I offer AnnotatedArrayPlot which comes in handy when your dataset is more than just a flat 2D array. The dynamic interface allows highlighting individual cells and possibly interacting with them. AnnotatedArrayPlot works the same way as ArrayPlot and accepts the same options plus Enabled , HighlightCoordinates , HighlightStyle and HighlightElementFunction . data = {{Missing["HasSomeMoreData"], GrayLevel[ 1], {RGBColor[0, 1, 1], RGBColor[0, 0, 1], GrayLevel[1]}, RGBColor[0, 1, 0]}, {GrayLevel[0], GrayLevel...
Post a Comment
Read more