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I have a density plot, for example
DensityPlot[Sin[x*y],{x,0,2pi},{y,0,2pi}].
Then I would like to collect points from this densityplot into a file so that I can always use ListDensityPlot to draw these points again, or I may draw these points by some other software.
I read several posts on how to do that for Plot, but how can I generalize them to DensityPlot?
data = Reap[DensityPlot[Sin[x*y], {x, 0, 2 Pi}, {y, 0, 2 Pi},
EvaluationMonitor :> Sow[{x, y, Sin[x*y]}]]][[2, 1]];
ListPlot3D[data]
compare to
DensityPlot[Sin[x*y], {x, 0, 2 Pi}, {y, 0, 2 Pi}]
{x,y} your solution evaluate the function f[x,y]' to DensityPlot` twice: one time for the DensityPlot value itself, and one for the Sow, as you put back f[x,y] in Sow. Is there a way to call f[x,y] on time only ?
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Jul 13, 2016 at 22:36
Table command, then use DensityPlot but the reason for doing the above, is to use the same sampling as that used by DensityPlot which can be different and not uniform as what one might pick using Table. Sometimes Plot uses an adaptive sampling. I
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DensityPlot cannot return easily the values on the grid with the plot itself.
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Jul 15, 2016 at 16:14
how about this?
lists = Table[
Sin[x*y], {x, 0, 2 \[Pi], \[Pi]/20}, {y, 0, 2 \[Pi], \[Pi]/20}];
ListDensityPlot[lists, Mesh -> None]
Or like this
lists = DensityPlot[Sin[x*y], {x, 0, 2 \[Pi]}, {y, 0, 2 \[Pi]}][[1,
1]];
ListDensityPlot[{#1, #2, Sin[#1 #2]} & @@@ lists, Mesh -> None]
Though DensityPlot only contains color info for z value.
However, you could obtain data from equivalent Plot3D
plot=Plot3D[Sin[x*y], {x, 0, 2 Pi}, {y, 0, 2 Pi}]
If you see the plot//FullForm, you can find point data contained in GraphicsComplex[list of data,__]
So to extract data, it is as simple as
plot[[1,1]]
You can check this by
ListDensityPlot[plot[[1,1]]]
