In gnuplot pm3d map plot a 3d data into a surface with color as value of "z". Lets say we have a data file something like this .. 0.00 0.00 0.00 0.00 1.00 0.00 0.00 2.00 0.00 0.00 3.00 1.9358 0.00 4.00 3.618 0.00 5.00 5.17 0.00 6.00 6.93 0.00 7.00 8.82 0.00 8.00 10.692 1.00 0.00 0.00 1.00 1.00 0.00 1.00 2.00 0.00 1.00 3.00 2.1318 .... ... In gnuplot prompt we will do something like this . set pm3d map; set dgrid 20,20 sp "data.dat" u 1:2:3 and this will produce a figure something like a figure as shown above. One of the big disadvantage of gnuplot in my opinion is not able to manipulate data. Specifically if you look at the way interpolation is done. There is very little you can do with you data. Here i will give you a simple example how to plot a 3d data (3 column data or x,y,z ) in python name with the help of matplotlib/numpy/scipy. One has to first mak