[ENH] Map widget

[kernc]

Issue

Add map widget for plotting geospatial data.

Includes

• Code changes
• Tests
• Documentation

[astaric]

Can you skip the owmap tests when only PyQt4 is available? As we will not drop support for PyQt4 for some time, it would be nice if the tests still passed.

[lanzagar]

1. Selections on an empty widget result in a crash.
2. Zoom to rectangle selection does not work for me.
3. Tooltip has duplicates if e.g. shape and color use the same var.
4. All other widget windows get closed with Esc on my system except for this one (anything different/non-standard here?)
5. When target is selected an error is shown if no learner. If learner is connected and target selected, removing the learner does not show the error (until deselect/select of target var).

Non-urgent wishes (for later PRs; to be discussed):

• This is very similar to Scatter plot so we should strive for similar controls (order of opacity/symbol size; location of jittering; zoom/select controls; etc)
• Also, scatter plot has class density which could be very relevant here as well.
  Maybe even more than the included heatmap feature. Even better, we should expand class density to support continuous vars, allow target selection, and include that in both widgets.

[ajdapretnar]

Documentation is prepared but waiting for some additional fixes (heatmap for classification and resolution regarding the test data set).

I am experiencing the same issues as @lanzagar with additional issue of labeling by name on airports data set. I get AttributeError: 'LeafletMap' object has no attribute '_label_values'. In essence, labeling by string doesn't work for me.

[kernc]

@ajdapretnar Have yet to confirm, but there may not be a classification heatmap so soon.

Zoom to rectangle selection does not work for me.

@lanzagar Any errors in the error console?

[lanzagar]

Bumping this to 3.3.10 as it is still under active development and needs documentation etc.

[codecov-io]

Current coverage is 89.27% (diff: 50.00%)

Merging #1735 into master will decrease coverage by 0.01%

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  Files            86         86          
  Lines          9112       9116     +4   
  Methods           0          0          
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+ Hits           8136       8138     +2   
- Misses          976        978     +2   
  Partials          0          0          

Powered by Codecov. Last update 4dad654...a83e3ee

[kernc]

@ajdapretnar Have yet to confirm, but there may not be a classification heatmap so soon.

Managed something.

[ajdapretnar]

That's exactly what I had in mind. Thanks! :) Will test it again next week!

[kernc]

Blocked on #1799.

[lanzagar]

Previous issues seem to be fixed.
Some new ones include:

• Changing lat/long var does not update map!
• Changing from a discrete to continuous target var for overlay has a bug
• Starting zoom is not correct (clicking the center button after that works)

[janezd]

I wholeheartedly approve this widget. MASAP.

[janezd]

Bumping the approval count.