CODEWITHSUNDEEP
gnuplotheatmap
user1539090
user1539090

Reputation: 75

Plotting 3D heatmap in gnuplot

I have a 4D data. The forth column is needed to be represented as color intensity. The other three columns will represent three different axes. I want to generate 3D heatmap using gnuplot. How can I do this?

Data Sample:

0 0 0 16

0 0 1 25

0 1 0 27

0 1 1 29

1 0 0 8

1 0 1 44

1 1 0 50

1 1 1 27

Upvotes: 0

Views: 4120

Answers (1)

mgilson
mgilson

Reputation: 310227

generating a 3D heatmap in gnuplot is the same as generating a 2D heatmap except you add an additional column to using. In other words, the datafile lays out a series of "scans" and adjacent "scans" are connected with quadrilaterals. e.g.

x1 y1 z11 c11
x1 y2 z12 c12
x1 y3 z13 c13
...
x1 yN z1N c1N
                 #blank line here
x2 y1 z21 c21
x2 y2 z22 c22
...
x2 yN z2N c2N
                 #blank line here
.
.
.
                 #blank line here
xN y1 zN1 cN1
xN y2 zN2 cN2
...
xN yN zNN cNN

Now you can plot this using splot 'datafile' u 1:2:3:4 w pm3d.

*Note that the x-values along a particular "scan" don't need to be constant -- It's just easier to visualize it that way at first.

As a very simple example, we can use the ++ special file:

set xrange [0:2*pi]
set yrange [0:2*pi]
splot '++' using 1:2:2:(sin($1)*sin($2)) with pm3d

You could make the same datafile via the following pseudocode:

do iy=0, ny
   y = (2*pi/ny)*iy
   do ix=0, nx
      x = (2*pi/nx)*ix
      z = y
      write x,y,z,sin(x)*sin(y)
   enddo
   write blank space
enddo

Upvotes: 1

Related Questions