Plot a list of matrices at heights in 3d scatter plot

Question

I have a file with a number of matrices separated by a newline. I can plot any one of these matrices as a heatmap as shown in http://gnuplot.sourceforge.net/demo/heatmaps.html

However, now I would like to visualize all the matrices together on the same graph by plotting each matrix at increasing values of z, where each point is a coloured dot. I am trying to achieve something similar to the following question,

Plot 3D Grid Data as Heat Map using gnuplot

but without the cubes, as dots are sufficient.

This is the data for one matrix:

 7.606193E-01 -2.706752E-01  1.605924E-01  9.973101E-01  6.646065E-01 -4.177295E-01 -5.101588E-01 -5.338852E-01 -9.443505E-01  6.273689E-01  4.401633E-01  9.428387E-01 -1.783963E-01  1.702644E-01 -9.304313E-01  3.995178E-01 
-1.574189E-01 -3.911715E-01 -5.581077E-01 -3.719385E-02  7.144460E-01 -3.147125E-01  4.237802E-01  6.533050E-01  5.385187E-01  8.391651E-02 -5.773817E-01  1.456075E-01  6.028832E-01  5.313966E-01  3.894490E-01  7.329324E-01 
 8.147309E-01 -8.286917E-01 -9.708381E-01 -6.634787E-02  8.603123E-01  8.952920E-01  6.777392E-01  4.347730E-01 -9.271995E-01  8.899992E-01  5.525438E-01 -7.496139E-01  7.592094E-01  3.412833E-01  1.220876E-01  7.281239E-01 
 6.915789E-01  3.365000E-01 -4.771788E-01  7.674200E-01  8.059295E-01  3.545558E-01  2.764826E-01  3.801301E-01 -6.679796E-01  1.163551E-01 -5.292152E-01 -3.500514E-01 -8.614216E-01 -8.356531E-02 -8.391827E-01  7.258298E-01 
 1.219247E-01  5.344889E-01  8.977039E-01 -5.708083E-01 -6.809624E-01 -5.687558E-01  3.830947E-01  9.990373E-01 -6.038938E-01  9.162573E-01 -4.214753E-01  4.186414E-01 -4.224649E-01 -9.376176E-01 -1.170071E-01  3.825447E-01 
-1.046988E-01  5.206562E-01 -9.832160E-01 -6.588389E-01  6.122716E-01  2.926736E-01 -8.736564E-01  9.977460E-01  8.937872E-01 -8.719974E-02 -7.742046E-01 -9.490100E-01  6.090313E-01  8.220433E-01  7.705420E-01  5.937839E-01 
 8.668659E-01 -5.811435E-01 -4.980876E-01 -5.458175E-02 -1.702000E-01 -9.681295E-01 -9.898823E-01  8.014537E-01  6.852101E-01  3.412942E-01 -4.313660E-01  6.886256E-01 -8.974125E-01  8.012120E-01  7.893018E-01 -1.869330E-01 
-1.168977E-01 -8.988775E-01 -2.580437E-01 -8.019403E-02  4.935626E-01  3.774684E-01  5.609375E-02  8.018482E-01 -9.803250E-01 -8.223162E-01 -7.441623E-02  7.592162E-01 -3.084599E-01  2.728176E-01 -7.114622E-01 -4.335231E-01 
 9.071215E-01  7.551532E-01  1.640213E-02 -2.627113E-01 -1.102158E-01 -3.576760E-02  7.584369E-02  3.586933E-01  9.412469E-01 -7.919924E-01 -7.883645E-01 -4.693788E-01 -1.549372E-01  1.823575E-01  4.206510E-01 -4.489097E-01 
 2.449895E-01 -4.566137E-02  5.805491E-01  3.808071E-01  4.885185E-01  9.662528E-01 -9.306209E-02  2.467101E-02  2.380986E-01 -9.053143E-01 -3.499831E-01 -4.224079E-01 -2.420047E-01  1.568254E-01 -1.696076E-01 -2.344714E-01 
-1.045739E-01 -2.254802E-01 -5.760012E-01  7.194423E-01  9.792110E-01 -7.514746E-01 -1.239218E-01 -3.922474E-01 -6.499553E-01  5.908898E-01  8.695512E-01 -6.576686E-01  7.101708E-01  6.389254E-01 -3.228182E-01  3.177363E-01 
-7.059239E-01 -8.482834E-01 -1.630977E-01 -9.891499E-01 -5.450270E-01 -6.303106E-01  1.596098E-01 -2.695453E-01  1.340886E-01 -3.888265E-01 -4.888381E-02  1.609239E-01  3.058087E-01  7.288026E-01  9.176123E-01  2.593470E-02 
-5.400585E-01  8.222967E-01  3.648388E-01 -6.635013E-01 -4.210275E-01 -2.741717E-01  1.431661E-01 -2.184412E-01 -6.006791E-01 -9.289613E-03  2.788451E-01 -2.769694E-01 -9.857075E-01 -5.143206E-01 -1.455316E-01  9.782214E-01 
-7.254217E-01 -1.668047E-01 -7.403084E-01  5.606276E-01  1.713349E-01  8.025852E-01 -9.133063E-01 -3.648469E-01  9.402033E-01 -2.317766E-01  7.771178E-01  8.427679E-01  5.951350E-02  9.725678E-01  7.514953E-01 -2.132574E-02 
 3.962623E-01 -8.680837E-01 -6.393657E-01  7.831294E-01 -5.947012E-02 -9.781432E-01 -8.829182E-01 -9.939770E-01  7.487056E-02 -7.578757E-01  6.196460E-01 -7.909356E-01 -1.149577E-01 -2.736676E-01  2.013560E-01  5.961972E-02 
 7.165400E-01 -2.371667E-01 -7.857778E-01  7.715441E-01  5.449374E-01  2.804987E-02 -1.380231E-01 -5.877602E-01  3.679530E-01  3.016719E-01 -5.242305E-01  1.064826E-01 -6.910435E-02  7.062310E-01  8.472682E-02 -9.717143E-01

score 4 · Accepted Answer · answered Mar 14 '18 at 12:10

I am not sure if I understood correctly, but it seems that you want each matrix as a heatmap at a fixed (arbitrary) z-value.

As mentioned on the link you posted, making a plot like that one would require (at least to my knowledge) a lot of scrambling around on gnuplot. However, you could have a rough idea by doing:

set term png
set out "tmp.png"

set view 80,30

splot "tmp" matrix u 1:2:(2):3 w p pt 5 ps 0.75 pal,\
      "tmp" matrix u 1:2:(1):3 w p pt 5 ps 0.75 pal,\
      "tmp" matrix u 1:2:(0):3 w p pt 5 ps 0.75 pal

Which would give you:

Not pretty, but works. You'd have to play around with the labels, tics and view parameters depending on how many matrices you have. Hope it helps!

When I implemented your solution, I initially had the problem that only the first matrix was shown on all levels, but adding `index`, such as plotting the 2nd matrix in the file with `splot "tmp" matrix index 2 1:2:(2):3 w p` addressed that. — Riddick, Mar 14 '18 at 18:47

score 3 · Answer 2 · answered Mar 14 '18 at 17:22

You could splot each matrix with image:

set ztics 1
set ticslevel 0
stats "data.dat" matrix nooutput
set xrange [-0.5:STATS_size_x - 0.5]
set yrange [-0.5:STATS_size_y - 0.5]

splot for [i=1:3] "data.dat" matrix using 1:2:(i):3 with image notitle

Or, depending on your need, you can also splot ... with pm3d:

set view 70,23
set ztics 1
set ticslevel 0
set pm3d interpolate 5,5
set autoscale xfix
set autoscale yfix

splot for [i=1:3] "data.dat" matrix using 1:2:(i):3 with pm3d notitle

Similar to my comment in Vinicius Placco's post, I just had to add `index i` to make sure it plots consecutive matrices from the file. — Riddick, Mar 14 '18 at 18:49

Plot a list of matrices at heights in 3d scatter plot

2 Answers2