Demo of Customizable Wagner I/II using d3-geo

Customize Projection

Length of Pole Line (c = 0.5)

0 1

Areal Inflation at 60° N/S (S₆₀ = 0)

0 100

Aspect Ratio (p = 200)

50 500

Customize Map

scale (140)

0 400

rotate (λ) (0)

-180 180

rotate (φ) (0)

-180 180

rotate (γ) (0)

-180 180

graticule spacing (10)

0 45

Customize Map Position

center (lon) (0)

-180 180

center (lat) (0)

-90 90

translate (x) (480)

0 960

translate (y) (250)

0 500

Rendered with:
d3.geoWagner2().poleline(0.5).inflation(0).ratio(200)
Böhm Notation of current configuration: ii@0.5-60-0-200 (Wagner II)

Final values that get passed to Wagner’s formula (here, rounded to 6 decimals):
cx = cy = m1 = m2 =

Final values as a single string (more convenient for sharing):

Note:
– This demo works with two decimals for c, p and S₆₀, but actually, more decimals are allowed in the formula (and have been used by Canters).

Return to default configuration by reloading this page.
Render predefined projections:

• Wagner I (0.5-0-200)
• Wagner II (0.5-20-200)
• approx. Canters W01 (optimisation of Wagner I) (0.72-0-211.5)
• approx. Canters W02 (optimisation of Wagner II) (0.7-20-195.5)
• approx. pole line length and aspect ratio of Equal Earth (0.7-0-205.5)

For the projection nowadays known as Wagner II, Karlheinz Wagner allowed to customize the generated map in regards of changing the pole line length, aspect ratio of the axis, and either to maintain equivalence or to add a defined amount of areal inflation.

Use the sliders in the section Customize Projection to play with Wagner’s configuration parameters and see what the results look like.
The sections Customize Map and Customize Map Position have been added for convenience and might be helpful or simply interesting to modify; they are not part of Wagner’s transformation method.

Please note that defining the pole line length differs from the solution of the Customizable Wagner VII/VIII and the Customizable Wagner IX.
There, it is defined as the limiting latitude of the parent projection.
Here, it is defined by (pole line length) divided by (length of the equator) i.e. a value of 0.5 will render an equator that is twice as long as the pole line.

There’s a reason for that, it’s given in my blogpost More Umbeziffern for d3-geo-projections (also available in German).

For general information about Wagner’s transformation method, read this blogpost or the article Das Umbeziffern – The Wagner Transformation Method.
For the d3 script source code used to render this projection, see Customizable Wagner Projections using d3-geo – Seven Of Nine.

This page utilizes code taken from d3indepth’s Projection explorer, thanks for sharing!