set terminal pngcairo enhanced font "arial,10" fontscale 2.0 size 3000, 1800
set output 'heatmaps.1.png'
unset key
set view map
set size ratio .6
set xtics border in scale 0,0 mirror norotate  offset character 0, 0, 0 autojustify
set ytics border in scale 0,0 mirror norotate  offset character 0, 0, 0 autojustify
set yrange [ 1.5 : 19.5 ] noreverse nowriteback
set xrange [ 0 : 1000 ] noreverse nowriteback
set cbrange [ -0.50000 : 7.50000 ]
set cbtics ("INIT" 0, "NOCOORD" 1, "ELECTION" 2, "WAIT" 3, "NORESPONSE" 4, "CHECK" 5, "COORD" 6, "REGULAR" 7)

set ytics ("syslab-04" 2, "syslab-21" 3, "syslab-22" 4, "syslab-ui0" 5,\
           "syslab-ui5" 6, "syslab-ui4" 7, "syslab-24" 8, "syslab-25" 9,\
           "syslab-26" 10, "syslab-v13" 11, "syslab-02" 12, "syslab-03" 13,\
           "syslab-v02" 14, "syslab-07" 15, "syslab-12" 16, "syslab-08" 17,\
           "syslab-10" 18, "syslab-05" 19)

set palette maxcolors 8
set palette defined ( 0 "blue", 1 "yellow", 2 "red", 3 "green", 4 "brown", 5 "black", 6 "pink", 7 "cyan" )
# remove the previous line and everything works ok - but I don't want that palette.
plot 'a.csv' matrix using 2:1:3 every ::2 with image