Is there a way to get contour lines in GIMP starting with a height or elevation map?

I'm looking for 1 pixel lines of a single color.

Edge detect doesn't really produce what I'm looking for
- too thick and multicolored.

I did find a script here, but it wouldn't work.

https://www.cartographersguild.com/s...ad.php?t=25929

I can brute force it using shink selection repeatedly, but would like to know if anyone's got a better solution.