Stitching difficulties with the ocean

[éric Thoreau]

Hello,

I've shot a pano using my DJI Air 3s; 

as a result, I have 137 images.

In PTgui, I'm using papywizard; the *.xml was created with xml-creator (thanks Kilian).

As you can see, my horizon isn't totally flat. I've tried my best but still not perfect.

When adding manual control points (4th screenshot, I'll see it''s kind of difficult to add some on the sea), what do I do next ?

Go back to the project assistance & launch the optimizer ?

Thanks

eric

[John Houghton]

Eric,  You can get a level and straight horizon by adding straight line control points of type "Line 1" on the horizon in each image.  (1 control point pair spanning the image).  The optimizer will attempt to get all of the line points in a straight line.  (The Papywizard horizontal spacing may be adequate).  Beware of the control point type selection reverting to the default "Vertical" when switching images.  This behaviour can be inhibited via settings in Tools Options.

John

[éric Thoreau]

Hello John,

I've added horizontal ctrl points on all horizon images (20 files) but still have this small issue I cannot correct.

Any idea on how to correct this problem ?

Thanks

[Erik Krause]

Am 31.08.26 um 14:13 schrieb éric Thoreau:

> I've added horizontal ctrl points on all horizon images (20 files) but
> still have this small issue I cannot correct.
> Any idea on how to correct this problem ?

Add another two pairs of control points with the same line number as the
other horizon points near the place where the issue appears, one pair in
each image. If this doesn't help, remove the control points on the
clouds in the respective image pair.

--
Erik Krause
http://www.erik-krause.de

[John Houghton]

[John Houghton]

On Monday, August 31, 2026 at 1:13:33 PM UTC+1 éric Thoreau wrote:

Hello John,

I've added horizontal ctrl points on all horizon images (20 files) but still have this small issue I cannot correct.

Any idea on how to correct this problem ?

(2nd attempt at a reply):  

Eric, I find it hard to advise when it's not clear exactly what you are doing and images are merely screenshots.  It's difficult to distinguish between what might be layers of land or cloud or sea near the horizon.  Is the position of the actual horizon clearly identifiable in all of the relevant images?  And are you using only horizontal line control points rather than straight line control points or a mixture of the two?  As Erik mentioned, control points on (moving?) clouds should generally be avoided if possible, though those in the far distance near the horizon are probably ok.

John 

[John Houghton]

On Monday, August 31, 2026 at 7:36:03 PM UTC+1 John Houghton wrote:

And are you using only horizontal line control points rather than straight line control points or a mixture of the two? 

eric,  Another thing to check:  If using only horizontal line control points, have you selected the option at the bottom of the Optimizer's Advanced screen "Hor / Vert control points" to "Include in single pass"?  If this not selected, the horizontal line points will have no effect on the way the images align with each other. 

John

[éric Thoreau]

360 pano pointe du Grouin

Thanks for your help.

Horizon isn't perfect ;) 

[John Houghton]

Eric,  Perhaps the dip in the horizon near the sun is due to control points being placed on features that look like the horizon but are not actually the horizon!  However, if you have Photoshop, the fault can be adequately corrected by using Edit->Transform->Warp.  It's worth doing. I think.  My attempt attached.

John

[Mike Cowlishaw]

This has been a 'running sore' with PTGui for many, many,  years.   A horizon over sea is (assuming it is clear and not foggy) is about the best example one can find of a straight line in the natural world.  Yet PTGui (presumably the PT underlying code) continues to be  incapable of recognising that straight line.

It's absurd that this has to be done manually (especially given that trying to correct it fails unless one selects precisely the correct pel to place on the line).   Maybe it's time to add some AI if the original code cannot be fixed?

Mike

[Erik Krause]

Am 03.09.2026 um 20:06 schrieb Mike Cowlishaw:

> A horizon over sea is (assuming it is clear and not foggy) is about
> the best example one can find of a straight line in the natural world.

Really? In my experience, the horizon at the sea is rarely a clearly
defined line. Most of the time, it’s a blurry, indistinct transition. In
this example, over large areas, it doesn’t even seem to be the horizon,
but rather a distant coastline. Or are these clouds?