Mercator with rotate. Incorrect conversion from projection to geographic coordinates about d3-geo

[mbostock]

It’s not a bug. That’s the expected behavior as I described due to the nature of spherical/cylindrical coordinates.

[mbostock]

The expected range of longitude is ±180, so 200 is the same as -160.

[dowhileforeach]

Surprisingly, proj4js has exactly the same bug:

const proj4 = require('proj4');

const proj = proj4('+proj=merc +lon_0=50 +ellps=WGS84 +datum=WGS84');

console.log(proj.forward([200,0])); // --> [16697923.618991036, 0]
console.log(proj.inverse([16697923.618991036, 0])); // --> [-160, 0]

Check It. Stackblitz

Apparently, there is some technical problem to take into account rotation by lambda when converting proToGeo...