I tried implementing but not sure where to put add the bins to my dimension. See below

```
const yMeasures = [
{
expression: ""loc"",
agg_mode: ""min"",
name: ""ymin""
},
{
expression: ""loc"",
agg_mode: ""max"",
name: ""ymax""
},
{
expression: ""loc"",
agg_mode: ""avg"",
name: ""yaverage""
}
]
const ybins = Math.floor((yMeasures.yaverage-yMeasures.ymin)/(yMeasures.ymax-yMeasures.ymin))*20
```

since I dimension by time and location, I am not sure where to put the bins.

```
return crossfilter
.groupAll()
.reduceMulti(timeChartMeasures)
.valuesAsync(true)
.then((timeChartBounds) => {
const timeChartDimension = crossfilter.dimension(['c5_datetime','loc'])
const timeChartGroup = timeChartDimension.group(ybins).reduceAvg(""speed"")
const [w, h] = getChartSize()
const numTicks = 5
heatChart = dc
.heatMap(parent)
.width(w)
.height(h)
.dimension(timeChartDimension)
.group(timeChartGroup)
```