Problem with Alaska and Hawaii rendering after upgrading to version 3.2.0

[cherihung]

I just upgraded the d3.js on my site to the latest 3.2.0 release. And I noticed that Alaska and Hawaii are showing up as rectangles in maps implemented using a FeaturesCollection json file. They are not rendering according to the MultiPolygon coordinates in the json file.

I'm basically using the same code as this example, http://bl.ocks.org/mbostock/2206590, which is also showing the same problem.

[jasondavies]

That example appears to contain three tiny counterclockwise polygons, which D3 treats as covering most of the sphere. In version 3.2, we modified the clockwise/counterclockwise detection slightly to be more accurate.

An example offending polygon appears in Virginia (as part of a MultiPolygon):

[[
  [-76.016553, 37.95325],
  [-75.994645, 37.95325],
  [-76.043938, 37.95325],
  [-76.016553, 37.95325]]]

At first glance, you might expect it to have zero area because the latitudes are all equal, but line segments are geodesics in D3, thus it actually has non-zero, negative area, which we treat as counterclockwise.

Leaving this open so @mbostock knows to update the example; I’d recommend using TopoJSON e.g. as used by more recent examples.

[cherihung]

Thanks @jasondavies! That fixed the problem for the existing maps I had.