title: How to add space between axis and line in D3 line chart?
body: <p>Given this simple chart I created:</p>
  
  <pre><code> var data  = [["2013-01-24 06:38:02.235191", 52], ["2013-01-23 06:38:02.235310", 54], ["2013-01-22 06:38:02.235330", 45], ["2013-01-21 06:38:02.235346", 53]],
    maxValue = d3.max(data, function (d) { return d[1]; }),
    margin   = {top: 20, right: 20, bottom: 50, left: 50},
    width    = 500 - margin.left - margin.right,
    height   = 300 - margin.top - margin.bottom,
    svg, x, y, xAxis, yAxis, line;
  
  $.each(data, function(index, val) {
      val[0] = new Date(val[0]);
    });
  
  x = d3.time.scale()
    .range([0, width])
  
  y = d3.scale.linear()
    .domain([0, maxValue])
    .range([height, 0]);
  
  xAxis = d3.svg.axis()
    .scale(x)
    .tickSize(4, 2, 0)
    .ticks(d3.time.days, 1)
    .tickFormat(d3.time.format("%m/%d"))
    .orient("bottom");
  
  yAxis = d3.svg.axis()
    .scale(y)
    // .ticks(5)
    // .tickValues([0, maxValue * 0.25, maxValue * 0.5, maxValue * 0.75, maxValue])
    .tickSize(4, 2, 0)
    .orient("left");
  
  line = d3.svg.line()
    .x(function(d) { return x(d[0]); })
    .y(function(d) { return y(d[1]); });
  
  svg = d3.select("#chart-holder").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
  
  x.domain(d3.extent(data, function(d) { return d[0]; }));
  y.domain(d3.extent(data, function(d) { return d[1]; }));
  
  svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis)
    .selectAll("text")
      .attr("transform", function(d) {
        return "rotate(-60)translate(" + -this.getBBox().height * 1.7 + "," +
          -this.getBBox().width/4 + ")";
      });
  
  svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);
  
  svg.append("path")
    .datum(data)
    .attr("class", "line")
    .attr("d", line);
  
  svg
   .selectAll("circle")
   .data(data)
   .enter().append("circle")
   .attr("fill", "#0b8da0")
   .attr("r", 3.5)
   .attr("cx", function(d) { return x(d[0]); })
   .attr("cy", function(d) { return y(d[1]); });
  </code></pre>
  
  <p>How can I add a space between axis and line, so it won't touch the axis.</p>
  
  <p>Also is there a way to force yAxis ticks to always start from 0, no matter what is the smallest value in the data set?</p>
  
  <p>Working example can be found here: <a href="http://jsfiddle.net/n7Vmr/" rel="nofollow">http://jsfiddle.net/n7Vmr/</a></p>