projection 'origin' method has been removed, no docs on how to migrate about d3-geo

[n1ywb]

of course it's been 10 minutes and I discovered that you can do it with the rotate function

.rotate([72.486237, -44.197227])

seems to center the map on my house

it's a bit different from origin b/c you have to flip the signs

the rotate docs could probably use some clarification on this use case, it seems pretty common

[mbostock]

You are looking an example from 2011 that was writing for D3 2.x. In 2012, D3 3.0 was released which introduced a more general rotation system for geographic projections; see Upgrading to 3.0 from the D3 3.x API Reference. However, I recommend that new code be written for D3 4.x which was released in 2016. The documentation for d3-geo’s projection.rotate includes more recent examples.

[n1ywb]

where are the examples? I don't see them in the documentation.

[mbostock]

The documentation for projection.rotate I linked to links to http://bl.ocks.org/mbostock/4282586. By my count the README links to 24 examples.

[n1ywb]

the release notes only say

"The albers.origin method has also been replaced by projection.rotate and projection.center"

[mbostock]

Right, which it was. I acknowledge that’s perhaps not sufficient to tell you exactly how to update code that uses albers.origin to use projection.rotate; the expectation is that you’ll read the documentation for those methods. And with apologies, I’m not going to rewrite four-year-old release notes to provide further details.

[n1ywb]

origin() was removed from ALL projections not just albers AFAICT. But I'm not suggesting you rewrite rewrite four-year-old release notes.

For the benefit of all future d3.js users who may run into this issue I am putting some example code right here in this ticket

d3.js v2 example:

var projection = d3.geo.azimuthal()
    .scale(380)
    .origin([-71.03, 42.37])
    .mode("orthographic")
    .translate([640, 400]);

d3.js. v4 example:

var projection = d3.geoAzimuthalEquidistant()
    .scale(380)
    .rotate([71.03, -42.37]) // Note the flipped signs
    .translate([640, 400]);

It's almost a 1:1 but note the reversed signed-ness; you normal lon/lat becomes a relative offset instead of an absolute position.

I'm done.

[mbostock]

Yes, there was also bonne.origin and azimuthal.origin. In 2.x, d3.geo.equirectangular and d3.geo.mercator didn’t support an origin property. (Along with d3.geo.albersUsa, though that’s been the case ever since by nature of it being a composite projection.)

The reason that bonne.origin and azimuthal.origin aren’t mentioned is because these classes were replaced as a whole. In 3.x, the Bonne projection moved to d3-geo-projection’s d3.geo.bonne; in 4.x, it was renamed to d3.geoBonne. The azimuthal projections likewise became d3.geoOrthographic and the like.

In 2.x, there was no generic projection interface, at least beyond a function that takes a point [longitude, latitude] as input and that returns [x, y]. Unlike in 3.x and later, which introduced projection.rotate, there were no generic projection methods, and so no generic projection.origin.

[n1ywb]

Here's a quick way to flip the sign on the coords; this effectively implements the origin() method AFAICT

projection.rotate(d3.geoRotation([lon, lat]).invert([0,0]));