Peirce Quincuncial Projection.

This week I’ve decided to experiment with the Peirce Quincuncial projection. In simple terms, this is a projection which is capable of projecting an equirectangular panorama onto a square. It’s similar to a stereographic projection as both of them represent a 360° field of view. The only difference between them is that a stereographic projection will produce a spherical image whereas Peirce Quincuncial will project the final image onto a square. If you are new to panoramic photography, please familiarise yourself with my previous posts on Equirectangular Panorama as you will need one to follow this step-by-step tutorial.

What you need is an equireclangualar panorama, Photoshop Flexify 2 plug-in and basic photoshop skills. Panoramas that have a clear distinction between the sky and the ground work best, unlike indoor panoramas. First open your panorama in Photoshop and launch Flexify 2.

Select equirectangular as input and Pierce quincunx as output and adjust the latitude, longitude and spin sliders until you get a square image. Then press OK and Flexify will process your image.

Next, open another document and make the canvas four times higher and wider that your projection. Then, move your projection onto the new canvass.

Then, you basically have to assemble your image from multiple copies of the original projection. However, to join the projections together, you will have to rotate them in order to match their edges as demonstrated in the two screenshots below.

Once you manage to assemble one row, you can then flatten the layers and duplicate it in order to save some time. Remember, you will still have to rotate the entire row in order to join it with the other one.

Keep duplicating the rows until you get something like this.

Then, rotate the image by 45 degrees and crop it to your taste and voila!

Thanks for reading and have fun.

For more inspiration visit the Pierce Quincunical Flickr group.

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