How to level a sea horizon?

[David W. Jones]

I have a sea horizon I shot from shore, handheld. No matter what I do,
the horizons on different images tilt different ways. I've tried using
the Assistant (it fails to find control points on one of the images, but
when I add control points, there's no improvement). I've tried using
horizontal lines on the horizons for each image, things still end up all
over the place. Using the Straighten button makes part of it a curve,
then it turns into tilted horizons again.

I've tried adding vertical lines on each image at right angles to the
sea surface. That just started throwing images around in weird vertical
places.

It's situations like this that really makes me wish Hugin had a "Find
horizontal lines" function...

Using Hugin 2020.0.0.2f576e5d5b4a on Debian Linux.

Ideas?

--
David W. Jones
gnome...@gmail.com
wandering the landscape of god
http://dancingtreefrog.com
My password is the last 8 digits of π.

[Gunter Königsmann]

Adding horizontal lines to at least a few images should do most of the trick (just add a control point pair with both control points at the sea level in the same image). Hugin now knows what is horizontal.

...and then you need to choose a projection that makes horizontal lines end up horizontal. Cylindrical should be fine. Alternatively in the panorama viewer you can drag the image to the point that makes this specifoc horizontal line to be projected as a straight line.

Kind regards,

Gunter.

[David W. Jones]

Gunther -

Thanks for the reminders. I added horizontal lines, tried cylindrical
projection, horizons don't come out level.

Drag the image to the point the specific horizontal line is projected as
a straight line? Sorry, not sure what that means.

> http://dancingtreefrog.com <http://dancingtreefrog.com>

[dkloi]

Have you tried putting horizontal control point pairs on different images? Example http://www.dkloi.co.uk/wp-content/uploads/2021/11/SeaHorizon.png