html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/pull/509#issuecomment-128193197,https://api.github.com/repos/pydata/xarray/issues/509,128193197,MDEyOklzc3VlQ29tbWVudDEyODE5MzE5Nw==,1217238,2015-08-06T00:30:31Z,2015-08-06T00:30:31Z,MEMBER,"@jhamman you should merge this once you and @clarkfitzg are happy. I'm about go offline for 6 days (backpacking in the Olympics).
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-128158707,https://api.github.com/repos/pydata/xarray/issues/509,128158707,MDEyOklzc3VlQ29tbWVudDEyODE1ODcwNw==,1217238,2015-08-05T21:45:53Z,2015-08-05T21:45:53Z,MEMBER,"@clarkfitzg any thoughts here?
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-128158577,https://api.github.com/repos/pydata/xarray/issues/509,128158577,MDEyOklzc3VlQ29tbWVudDEyODE1ODU3Nw==,1217238,2015-08-05T21:45:13Z,2015-08-05T21:45:13Z,MEMBER,"These tests look great -- thanks!
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-127507325,https://api.github.com/repos/pydata/xarray/issues/509,127507325,MDEyOklzc3VlQ29tbWVudDEyNzUwNzMyNQ==,1217238,2015-08-04T07:30:37Z,2015-08-04T07:30:37Z,MEMBER,"Decided to try reorganizing things and got sucked in, so I ended up making a PR to your fork with some tweaks:
https://github.com/jhamman/xray/pull/1
This assuredly still needs more tests -- mostly to verify that every plot types ends up with consistent levels.
Here's my demo notebook:
https://gist.github.com/shoyer/e6fafbc672021600d9f3
and a teaser:
The main difference in functionality is in my PR is that `vmin` and `vmax` _cannot_ be set independently of `levels`, if levels is provided as a list. That seemed a little too flexible, and this way we can get a consistent result across all four plot types. Are there any cases where you _would_ want to set `vmin`/`vmax` to something other than the first and last levels?
Also, I entirely replaced the levels calculation in contour/contourf with our calculated levels instead of merely trying to replicate it. That ensures things are guaranteed to be exactly identical across all plot types.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-127364421,https://api.github.com/repos/pydata/xarray/issues/509,127364421,MDEyOklzc3VlQ29tbWVudDEyNzM2NDQyMQ==,1217238,2015-08-03T18:35:04Z,2015-08-03T18:35:04Z,MEMBER,"> Options for when levels is provided and extend == None:
I would opt for your solution 2. I think this basically means using `levels[0]` and `levels[-1]` if levels are provided explicitly instead of `vmin`/`vmax` (which are being ignored anyways).
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-127164584,https://api.github.com/repos/pydata/xarray/issues/509,127164584,MDEyOklzc3VlQ29tbWVudDEyNzE2NDU4NA==,1217238,2015-08-03T08:39:18Z,2015-08-03T08:39:18Z,MEMBER,"Looking at the matplotlib source code, here's how they figure out levels in contour/contourf:
https://github.com/matplotlib/matplotlib/blob/714d18788320325d0bff75184f62d472f67ceb91/lib/matplotlib/contour.py#L1143
It looks like they use `MaxNLocator` to do this:
http://matplotlib.org/api/ticker_api.html#matplotlib.ticker.MaxNLocator
It should be pretty straightforward to use that here.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509
https://github.com/pydata/xarray/pull/509#issuecomment-127163088,https://api.github.com/repos/pydata/xarray/issues/509,127163088,MDEyOklzc3VlQ29tbWVudDEyNzE2MzA4OA==,1217238,2015-08-03T08:29:34Z,2015-08-03T08:32:11Z,MEMBER,"Some feedback:
1. matplotlib seems to have nice heuristics for picking level splits with contour plots. I wonder if it would be feasible to copy that logic here when setting our own discrete levels? Compare:
`ds.t2m[3].plot(levels=6)`
vs `ds.t2m[3].plot.contourf()`
2. The logic for inferring the `extend` keyword argument needs to be updated to handle `levels`:
`ds.t2m[3].plot(robust=True, levels=[200, 250, 260, 270, 280, 290, 350])`
3.`imshow`, `pcolormesh` and `contourf` seem to deal with an explicit list of `levels` the exact same way. That's a relief. The plots look exactly the same.
4. As you noted, `contourf` currently crashes if you supply `levels` as an integer. This should be fixed, probably by converting `levels` into a 1d array / list if they are supplied as an integer before passing it into `contourf`. This would actually be more broadly useful, because currently there is no way to supply a non-default integer number of levels with `contourf` -- matplotlb appears to only expose the `N` argument when it is used positionally.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98629509