can't impute binned field

[iliatimofeev]

Vega-lite partial spec (full VL spec)

  "encoding": {
    "x": {
      "bin": {"maxbins": 30},
      "field": "IMDB_Rating",
      "type": "quantitative"
    },
    "y": {
      "field": "IMDB_Votes",
      "type": "quantitative",
      "aggregate": "sum",
      "impute": {"value": 0}
    },
    "color": {"field": "Major_Genre", "type": "nominal"}

Expected (proposed Vega spec):

problem with generated spec

"defined": {
    "signal": "datum[\"bin_maxbins_30_IMDB_Rating\"] !== null && 
              !isNaN(datum[\"bin_maxbins_30_IMDB_Rating\"]) &&                                                                              
              datum[\"sum_IMDB_Votes\"] !== null &&
              !isNaN(datum[\"sum_IMDB_Votes\"])"
 }

bin_maxbins_30_IMDB_Rating is undefined after impute, impute key is bin_maxbins_30_IMDB_Rating_mid

[iliatimofeev]

Another not working impute of binned field

vega editor

[domoritz]

Looks like we have not implemented imputation correctly for binned data. I suspect we would be okay with imputing before binning but I'm not sure.

[iliatimofeev]

I'm a bit confused with imputing before binning.

If I'm correct impute in the encoding of X and Y chanal interpreted as imputing with the key as the second axis. And if the second axis is binned than key should be binned field. So as I understand it should be binning before imputing

[domoritz]

imputing before binning: impute over the raw values (probably super expensive)
impute after binning: impute the binned values and add 0 in your example (probably better now that I think about it)

[domoritz]

Here is a simpler example: https://vega.github.io/editor/#/url/vega-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-yAA

[kanitw]

• Binned Stack Area Broken #2936 is another case of this.