Is there a tutorial on how to Level Out the Ocean Line?

[Whitemagus]

Hi is there a tutorial on how to level out the ocean horizontaly?

Because I have placed the horizontal points and one other point between images of ocean line.

However I still not get a perfect horizontal line of the ocean it is close but good.

[John Houghton]

Select the Advanced mode of the optimizer and near the bottom of the page, select the Hor / vert control points option as "Include in single pass".  Then run the optimizer.  Or are you already doing that?

John

[Whitemagus]

What I have been doing is cheking the Yaw and Pitch and the Sher (vert) on the Global lens profile, but no I never tried with   Hor / vert control points option as "Include in single pass". 

I will try to see if it improves.

[Whitemagus]

It did improve quite a bit but I still see a bit of a bump.

is this as good as it gets?

[John Houghton]

It depends on what other control points you might have in the images.   Alternatively, another option that you could try is to use straight line points.  Select the cp type as New line.  The next point you create (on the horizon) will be of type Line 1.  Then create points along the horizon in the various images, now selecting Line 1 as the control points type.  You don't create the two points on the same feature in the two windows.  Just click somewhere along the line each time (like vertical line points).  Beware that when you switch to a different pair of images, you will need to re-select Line 1 as the cp type.  (This resetting back to the default type can be inhibited by visiting Tools->Options->Control point Editor and unchecking that option).  You just sprinkle points all along the horizon. The optimizer will try to get all of the points into a straight line. 

John

[Whitemagus]

ok that worked it still left a tiny bump but that can be quickly removed in ps. 

However there is still a problem that I am not sure, as you can see in the image the water level is not at the exact middle of the image and it is not even parallel is this alright? (because the way the sphere is mapped) or should it be at the center?

[John Houghton]

The horizon should not be exactly aligned with the centre line of the window because you are clearly not at sea level yourself.  To understand why:  draw a diagram showing a circle with a mountain sticking up.  Then draw a line from its top, tangential to the circle, and also a "horizontal" line from the mountain top (ie. at right angles to the radial line from the circle's centre ).

John

[Whitemagus]

Right so it wont be parallel also because it will follow the UV mapping of the 360º sphere. Correct? 

[John Houghton]

On Sunday, November 30, 2025 at 3:58:14 PM UTC Whitemagus wrote:

Right so it wont be parallel also because it will follow the UV mapping of the 360º sphere. Correct? 

Sorry, but I don't know what "UV mapping means".  If this relates to the earth not being a perfectly spherical object, then the horizon might not be perfectly straight and horizontal.  But in my experience, I do find that the horizon behaves as I expect.  Searching back to find an example with a reasonable expanse of horizon, I found this one from 2012  (Ilfracombe):

in your example, it might be that there are distortions arising from attempts to get the cp distances as low as possible when there are maybe significant parallax issues.  (Your mention of optimizing shear parameters was slightly worrying, as your camera images are very unlikely to be suffering from shear distortion).  But I don't suppose anybody is going to be subjecting your panoramas to critical viewing with a ruler!

John

[Whitemagus]

UV Mapping is the way the image wraps around the 360º sphere, the UV represents the horizontal and vertical axis of the image (the image below refers to a ptgui map) I was refering to the distortion of the horizontal lines it is more noticiable in the top and bottom of the map . Humm there is some deep thinking in there when you say  (" If this relates to the earth not being a perfectly spherical object, then the horizon might not be perfectly straight and horizontal") could be yes. Parallax from my camera is calibrated as good as possible, I use one of the ninja products and the bublle is always in middle of  corse it is not perfect because of the weight of the camera that is havy... 

Yeah, it will be subjected to the ruler because I will use it for rendering and light and the sky line is important for composition, but I think at this point it is better to test it with a render engine to see how it handles.

Anyway I am impressed with the support and the PTgui software, the results are quite good.   

   

[Whitemagus]

ps. I just got the software like a moth ago I checked the shear just for experimental purpures, I will uncheck it on the next project to see the results. 

[Whitemagus]

Hi John, 

just a quick update, I finally figher it out that by placing a horizontal line not only on the images but on the start of the ocean line and then at the and the end of the last image, it will work really well. Now I get a really nice (parallel to the middle axis) skyline.

Thanks again Jonh. 

[Erik Krause]

Am 30.11.2025 um 20:18 schrieb Whitemagus:

> Humm there

> is some deep thinking in there when you say (" *If this relates to the

> earth not being a perfectly spherical object, then the horizon might not be

> perfectly straight and horizontal"*) could be yes.

The horizon is nearer, as you might think. If you stand at sea level,
it's about 4.4km away, even at an altitude of 10,000 m, it's only about
360 km. Even at much greater heights, the horizon is perfectly vertical
in equirectangular projection, as are all lines, which have the same
angular distance to the horizon.

The earth diameter at the poles is 42km less than at the equator. That
is 0.33%. I'd say, for any viewpoint on earth, the horizon is far too
near, as to show a perceivable amount of deviation from a straight line
in equirectangular projection.

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

[Whitemagus]

Hi Erik,

" Even at much greater heights, the horizon is perfectly vertical *

in equirectangular projection, as are all lines, which have the same
angular distance to the horizon."

You mean horizontal not vertical.

Wow very interesting indid I am suprized how close the sky line is at sea level.

Yeah so in short, the skyline of an ocean represented in the equirectangular projection will be an horizontal line.

[Erik Krause]

Am 01.12.2025 um 22:36 schrieb Whitemagus:

> You mean horizontal not vertical.

Indeed. I always mix them up, since as a climber my horizon is often
vertical ;-)

> Wow very interesting indid I am suprized how close the sky line is at sea
> level.
> Yeah so in short, the skyline of an ocean represented in
> the equirectangular projection will be an horizontal line.

Yes. And it should be at or near the horizontal center line in Pano
Editor, otherwise it will be bent in any panorama viewer.