The blog of

Fri July 01, 2022 13 Projections for 2022 (Part 7)

A collection of my own experiments
(see Intro for further explanations)

July: Guyou-Wagner

Original Creator Emile Guyou (1887) / Karlheinz Wagner (1941)
Group Miscellaneous
Property Compromise
Remarks Weighted arithmetic mean of the Guyou and the Wagner VII projections.
My variation 2018

All projections of this year’s calendar are experimental – but this one is as experimental as it gets. When I created it, I had no specific result in mind. I had no stated goal. I just was curious to see how the arithmetic mean of a conformal and an equivalent projection would look like.

I chose to mix the (conformal) Guyou and the (equivalent) Wagner VII projections, both centered to 15°W[1]. My first attempt was the ordinary arithmetic mean, but seeing the result I decided to throw in a little weighting: The projection shown above is weighted 2:3 in favor of the Wagner VII. I was pleasantly surprised when I inspected the distortions, because they are mostly pushed into the ocean. Only New Zealand gets inflated quite a bit – and more importantly, the inflations rise significantly within New Zealand’s area: From roughly 2.2 at the northernmost tip to ≈12.6 in the Southwest. That is unfortunate, but on the whole I think that you can call it a favourable distribution of distortions.

Regrettably, the outer form does not allow many practical applications of this projection. It could serve as a wall map that catches attention but still is ordinary enough to pull actual information from it. But apart from that, there’s probably not much left. Nonetheless I like it enough that I will add it to my Projection Collection in a few days.

Next month, we’ll have a projection that is useful – in my opinion. But I don’t think it’ll meet with much approval.

P.S.: In the printed version of the calendar I used a different imagery for the Guyou-Wagner; namely the map image you’ve seen in January on the Wagner IX Autobiographical. Meanwhile, I don’t like that one anymore, so for the image here on the blog I resorted to an old acquaintance, the Natural Earth Cross-blended Hypsometric Tints.

P.P.S.: This isn’t the first public presentation of the Guyou-Wagner, I first showed it in the “Experimental projections” thread of the mapthematics forum. A highly recommendable thread since a few very interesting projections are presented.

P.P.P.S.: And happy birthday, Dad! 🙂


  1. 15°W was chosen as projection center in order to prevent the sliced Europe you get when the projection is centered to the Greenwich meridian. See the image at Wikipedia: Guyou hemisphere-in-a-square projection.

My 2022 Map Projection Calendar

To read another part of my 2022 map projection calendar series, select the desired month.


One comment

Sorry, it’s currently not allowed to add new comments.
It’ll be possible again soon.

(Well, I hope at the end of September 2023 at the latest…)

Alexandre Canana

I hope your dad is having a nice birthday! BTW, I really like the Guyou-Wagner!
Fri July 01, 2022 10:39 pm CEST   –    2 replies

Tobias Jung

Thank you for both! :-)
Sat July 02, 2022 7:24 pm CEST

Alexandre Canana

No problem, I hope you continue creating and adding all these great projections, be they your own or others's
Sun July 03, 2022 12:06 am CEST

Sorry, it’s currently not allowed to add new comments.
It’ll be possible again soon.

(Well, I hope at the end of September 2023 at the latest…)

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