While viewing the tour on Roundme you can choose the projection type which fits to its content.
There are different projection types available and you can switch them in the 'More Functions' menu:

Every projection type is addressed for different types of content and we would recommend you to test them all to see what projection works best with your panoramic images.
Here you can find some basic info related to the projection types on Roundme.

Normal Projection
It is a standard 3D projection, also called rectilinear or gnomonic projection. At narrow viewing angles (<100°) it's like the natural human viewing, but at wide viewing angles it distorts very strong at the edges.

Fisheye Projection
In a fisheye projection the distance from the center of the image to a point is close to proportional to the true angle of separation.
With the fisheye Projection it is possible to minimize the problems of the normal projection at wide viewing angles. The distortion at the edges is much better but "straight-lines" which don't go through the center of the view become curved.

Stereographic projection
Stereographic projection is more extreme type of fisheye projection. It allows much larger viewing angles, which could cause extreme distortion at the edges. 

Little Planet projection
Little Planet projection is an extreme case of fisheye projection.
With this projection, while looking at the bottom, it's possible to create very nice "Little Planet Views". This is a remapping of full spherical panorama to a 360 degree fisheye image with the nadir in the center and the zenith at the circle border.

Architectural Projection
This projection keeps the "vertical lines" straight in the panorama when looking up and down to prevent the possible distortion displaying the urban objects. It is usually not possible to look fully up and down using this projection type, so we use Architectural Projection only in the "middle" of the panorama. When looking more up and down it switches back to Normal Projection, so it is possible to view fully up and down.

Panini projection
The Panini projection is a projection that can render convincing simulated perspective views of scenes up to 150 degrees wide.
The Panini projection is suitable for architectural subjects, especially interiors. It works best for views with a single central vanishing point - straight down a city street, or the aisle of a church, for example. However it is good for oblique interior and street views too. It can make nice city-scapes, but is not suitable for close-up exterior views of buildings, especially when looking toward a corner of the building.

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