taxi demo: trip_distance units don't match between table and chart

[dalogsdon]

In the taxi demo notebook (using trips data) the table shows distance as a number and the charts show that number as a distance in meters. I don't see where is is configured, and the original data file doesn't seem to indicate this.

Is this a default Vega behavior and is it something we need to fix?

[peller]

see vega/vega-lite#1459