Draw the line use the same y values, plots line at the bottom

Question

I have the same question with it

When use the same value in yAxis ，the plots line at the bottom

This is my code:

var data = [
           


        

Answer 1

The problem is that you're setting the input domain of your ranges using d3.extent. If all the values are the same, everything is going to map to a 0 y coordinate. To start the y scale at 0, replace

y.domain(d3.extent(data, function (d) {
  return d.roundTripTime;
}));

with

y.domain([0, d3.max(data, function (d) {
  return d.roundTripTime;
})]);