Question

I am drawing a chart with d3.js using d3.scale.log for the x axis in combination with a custom labels. Unfortunately the labels run into each other … any hints on how to make this work?

var width = 400;
var x = d3.scale.log().domain([1, 1000]).range([0, width]);

var formatSi = d3.format(".4s");
var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom")
    .tickFormat(function(d, i) {
        return formatSi(d) + 'Hz'
    });

var svg = d3.select("#chart")
    .append("svg").attr("width", width)
    .attr("height", 200)
    .append("g").attr("transform", "translate(20,20)");

([1, 3, 6, 9]).forEach(function(d) {
    x.domain([1, Math.pow(10, d)]);
    svg.append("g").attr("class", "axis x")
        .attr("transform", "translate(0," + d * 2 + "0)")
        .call(xAxis);
});​

A working example of this code is on jsfiddle

Answer 1

figured it out. Trick is to not use .tickFormat to supply the formatting function, but rather the .ticks method which in turn will apply the supplied formatting function to the .tickFormat method of the scale.

var width = 400;
var x = d3.scale.log().domain([1, 1000]).range([0, width]);

var formatSi = d3.format(".4s");
var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom")
​    .ticks(5,function(d, i) {
        return formatSi(d) + 'Hz';
    });

var svg = d3.select("#chart")
    .append("svg").attr("width", width)
    .attr("height", 200)
    .append("g").attr("transform", "translate(20,20)");

([1, 3, 6, 9]).forEach(function(d) {
    x.domain([1, Math.pow(10, d)]);
    svg.append("g").attr("class", "axis x")
        .attr("transform", "translate(0," + d * 2 + "0)")
        .call(xAxis);
});

The result is still not entirely satisfying as the system seems to have trouble placeing labels when the ticks are close together …