Fill contour between two curves!

[PlanetGus]

@PlanetGus

What’s your script?

Oops, just seen it.
It seems like you’re not using -Sb right?

@PlanetGus

gmt plot file.txt -i0,3,2 -Gred@90 -Sb${vecste}q+b -l"red > blue"

You, on the other hand, are plotting three points that GMT converts to closed polygon