gnuplot: 2D plot of a matrix of data

Question

How can I plot (a 2D plot) a matrix in Gnuplot having such data structure, using the first row and column as a x and y ticks (the first number of the first row is the number of

Answer 1

You can plot this data format using matrix nonuniform.

To get a heatmap you can plot either with image (regular grid, no interpolation, one quadrangle for each data point), or splot with pm3d (supports also irregular grids and interpolation, plots one quadrangle for four neighboring data points.

1. with image

   set autoscale xfix
   set autoscale yfix
   set autoscale cbfix
   plot 'data.dat' matrix nonuniform with image notitle
   

2. pm3d

   set autoscale xfix
   set autoscale yfix
   set autoscale cbfix
   set pm3d map
   splot 'data.dat' matrix nonuniform notitle