delete duplicates from vertices before passing to voronoi

[luke3141]

This fixes the problem where a scatter plot (as well as other types of plots that use scatter, including lines that use scatter to determine the mouse-over areas) generates an error for recent versions of d3 (after about 3.3.7) and where there are overlapping points.

The problem is that voronoi() requires the vertices that it's passed to not contain duplicates. (see: https://github.com/mbostock/d3/wiki/Voronoi-Geom#wiki-_voronoi).

This solves issues #330 and #368/#427. It may be a better fix than the latter as it fixes the underlying cause. I also found cases where 427 did not fix the problem.

[Filoni]

Works brilliantly, thanks for this!

[TheRiver]

I can confirm that this fixed the problem with duplicate points in line graphs for me. Thanks!

[mmacfadden]

Is there a plan to merge this into the head. It appears that several people are facing this issue.

[luke3141]

@mmacfadden, the readme has been recently updated (see: https://github.com/novus/nvd3/blob/master/README.md) which talks about a refactoring of the code, and hence no pull requests are being accepted except on the new branch (refactor/2.0.0-dev).

I've checked, and the same problems still exist with the refactored code. Hence I'll endeavour to rebase this pull request sometime in the next week.

[DavidSouther]

Closing in favor of #584

[ghost]

Thank you. This was killing me and this patch fixed my issue. Hopefully it gets pulled into the main trunk.

[liquidpele]

I'm re-opening this just to track this concept... a better solution than #880 should be done, and this is probably part of that.. but we also need a way to get at the multiple point data on hover for the tooltips.

[liquidpele]

This was actually done at some point by someone I think.

[AgDude]

This was implemented in #1934