NVD3 scatter plot tick spacing with only a few values

Question

Why is it that when there are only a few values in an NVD3 scatterplot, the tick spacing spreads out immensely? I would think the ticks should be independent of the number of values, but that doesn't seem to be the case.

Compare this plunker with their example. The only difference is the number of values being plotted, and yet their example shows many ticks, whereas my plunker shows only a few.

How can I cause the ticks to space nicely at all zoom levels when the plot is meagerly populated?

I thought about defining specific tickValues like this:

chart: {
    type: 'scatterChart',
    // ...
    xAxis: {
        // ...
        tickValues: d3.scale.linear().domain([-100,100]).ticks(500)
    },
    yAxis: {
        // ...
        tickValues: d3.scale.linear().domain([-100,100]).ticks(500)
    },
    zoom: {
        enabled: true
    }
}

but that only looks decent at certain zoom scales.

Answer 1

There's an option for ticks that I missed, as mentioned by krispo:

chart: {
    type: 'scatterChart',
    // ...
    xAxis: {
        // ...
        ticks: 10
    },
    yAxis: {
        // ...
        ticks: 10
    },
    zoom: {
        enabled: true
    }
}

plunker