Convert your image to .bmp
, then run it through autotrace
autotrace --centerline --error-threshold 0.5 iceland.bmp --output-file iceland.eps
Convert EPS to HPGL, then Optimise it
pstoedit -f plot-hpgl -pagesize a4 iceland.eps iceland.hpgl &&
hpgl-distiller -i iceland.hpgl -o iceland_optimal.hpgl
Then plot!