折线图在图表上没有达到正确的值并且有一条平滑的线

Question

下面是我的折线图，其中我使用 2 条线来显示不同的值，

一条线是蓝色的，另一条是红色的。

我希望线条有尖点。我希望这条线位于我拥有的正确 vaule 上。例如，如果 '28 dec' 是值 '4' 并且 '29 dec' 是值 '2' 并且 '30 dec' 是值 '5'，现在这些值并没有完全达到例如 'Dec 25' 的数字该值为 3，但在图表上，该线低于 3，看起来像 2.5。这是因为这条线是平滑的而不是锐利的吗？

我希望看到线条上下起伏，边缘锐利且不平滑。如果这是有道理的。我希望这是有道理的，因为我正在为此苦苦挣扎

我创建的 js fiddle 是：https://jsfiddle.net/dave1231/cexLbfnk/2/

如果有人能告诉我，我会非常感激。

提前谢谢你！

这是我的 HTML：

<div id="LineChart"></div>

这是我的 CSS：

  #search {
     position:absolute;
    top: -2%;
 }

 #LineChart{
  text-align:center;
}

.tablebad thead tr {
    background-color: #eee;
}

.tablegood thead tr th {
    background-color: #eee;
}


path.line {
    fill: none;
    stroke: #004ecc;
    stroke-width: 4px;
  }

  path.line2 {
    fill: none;
    stroke: #cc0000;
    stroke-width: 4px;
  }

  path.area {
    fill: #e7e7e7;
  }

  .guideline {
    margin-right: 100px;
    float: right;
  }

  .axis path,
  .axis line {
    fill: none;
    stroke-width: 5px;
  }

  .x.axis path {
    display: none;
  }

  .y.axis path {
    display: none;
  }

  .grid .tick {
    stroke: black;
    stroke-width: 0.2px;

    }
#fade p {


    text-align: center;
    animation: fadein 4s;
    -moz-animation: fadein 4s; /* Firefox */
    -webkit-animation: fadein 4s; /* Safari and Chrome */
    -o-animation: fadein 4s; /* Opera */
}

#fade ul,li {

    animation: fadein 4s;
    -moz-animation: fadein 4s; /* Firefox */
    -webkit-animation: fadein 4s; /* Safari and Chrome */
    -o-animation: fadein 4s; /* Opera */
}
@keyframes fadein {
    from {
        opacity:0;
    }
    to {
        opacity:1;
    }
}
@-moz-keyframes fadein { /* Firefox */
    from {
        opacity:0;
    }
    to {
        opacity:1;
    }
}
@-webkit-keyframes fadein { /* Safari and Chrome */
    from {
        opacity:0;
    }
    to {
        opacity:1;
    }
}
@-o-keyframes fadein { /* Opera */
    from {
        opacity:0;
    }
    to {
        opacity: 1;
    }
}

这是我的 d3.js：

var margin = {
    top: 0,
    right: 90,
    bottom: 30,
    left: 50
  },
  width = 1200 - margin.left - margin.right,
  height = 500 - margin.top - margin.bottom,
  padding = 1;

var parseDate = d3.time.format("%d-%b-%y").parse;

// Set the ranges
var x = d3.time.scale()
  .range([10, width - 15]);

var x2 = d3.scale.ordinal().rangePoints([10, width], .10)

var y = d3.scale.linear()
  .range([height, 100]);

var xAxis = d3.svg.axis().scale(x2)
  .orient("bottom")
  .tickFormat(d3.time.format("%b %d"))
  .ticks(4)
  .tickPadding(2);

var yAxis = d3.svg.axis().scale(y)
  .orient("left");

var valueline = d3.svg.line()
  .interpolate("basis")
  .x(function(d) {
    return x(d.date);
  })
  .y(function(d) {
    return y(d.XMAS);
  });

var valueline2 = d3.svg.line()
  .interpolate("basis")
  .x(function(d) {
    return x(d.date);
  })
  .y(function(d) {
    return y(d.JANSALES);
  });

//florida

var chart1 = d3.select("#LineChart")
  .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 + ")");

//needed for the grid
function make_y_axis() {
  return d3.svg.axis()
    .scale(y)
    .orient("left")
}

data1 = [{
    "date": "24-Dec-12",
    "XMAS": 2,
    "JANSALES": 0
  }, {
    "date": "25-Dec-12",
    "XMAS": 3,
    "JANSALES": 0
  },

  {
    "date": "26-Dec-12",
    "XMAS": 1,
    "JANSALES": 0
  },

  {
    "date": "27-Dec-12",
    "XMAS": 2.0,
    "JANSALES": 0
  },

  {
    "date": "28-Dec-12",
    "XMAS": 4.0,
    "JANSALES": 0
  },

  {
    "date": "29-Dec-12",
    "XMAS": 4.0,
    "JANSALES": 0
  }
  ,

  {
    "date": "29-Dec-12",
    "XMAS": 5,
    "JANSALES": 0
  },

  {
    "date": "30-Dec-12",
    "JANSALES": 3.0
  },

  {
    "date": "31-Dec-12",

    "JANSALES": 2.0
  },

  {
    "date": "01-Jan-13",

    "JANSALES": 3.0
  },

  {
    "date": "02-Jan-13",

    "JANSALES": 1.0
  },

  {
    "date": "03-Jan-13",

    "JANSALES": 3.0
  },

  {
    "date": "04-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "05-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "06-Jan-13",

    "JANSALES": 1.0
  },

  {
    "date": "07-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "08-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "09-Jan-13",

    "JANSALES": 3.0
  },

  {
    "date": "10-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "11-Jan-13",

    "JANSALES": 3.0
  },

  {
    "date": "12-Jan-13",

    "JANSALES": 3.0
  },

  {
    "date": "13-Jan-13",

    "JANSALES": 2.0
  },

  {
    "date": "14-Jan-13",

    "JANSALES": 1.0
  }
];


var color = d3.scale.ordinal().range(["#004ecc", "#cc0000"]);
//d3.csv("data.csv", function(error, data) {
data1.forEach(function(d) {
  d.date = parseDate(d.date);
  d.XMAS = +d.XMAS;
  d.JANSALES = +d.JANSALES;
});

// Scale the range of the data


x.domain(d3.extent(data1, function(d) {
  return d.date;
}));
y.domain([0, 10]);

x2.domain(data1.map(function(d) {
  return d.date;
}));

//add the grid
chart1.append("g")
  .attr("class", "grid")
  .call(make_y_axis()
    .tickSize(-width, 0, 0)
    .tickFormat("")
  )

chart1.append("path")
  .attr("class", "line")
  .attr("stroke", "red")
  .attr("d", valueline(data1));

chart1.append("path")
  .attr("class", "line2")
  .attr("d", valueline2(data1.filter(function(d) {
    return d.date > parseDate("29-Dec-12");
  })));

// Add the X Axis
chart1.append("g")
  .attr("class", "x axis")
  .attr("transform", "translate(0," + height + ")")
  .call(xAxis);

// Add the Y Axis
chart1.append("g")
  .attr("class", "y axis")
  .call(yAxis);

chart1.append("text")
  .attr("transform", "translate(" + (width + 3) + "," + y(data1[0].JANSALES) + ")")
  .attr("x", ".1em")
  .attr("y", "-40")
  .attr("text-anchor", "start")
  .style("fill", "red")
  .style("font-size", "15")
  .style("font-weight", "bold")
  .text("JAN SALES");

chart1.append("text")
  .attr("transform", "translate(" + (width + 3) + "," + y(data1[0].XMAS) + ")")
  .attr("x", ".1em")
  .attr("y", "10")
  .attr("text-anchor", "start")
  .style("fill", "steelblue")
  .style("font-size", "15")
  .style("font-weight", "bold")
  .text("XMAS");

//plus 1: animation

var curtain = chart1.append('rect')
  .attr('x', -1 * width)
  .attr('y', -1 * height - 2)
  .attr('height', height)
  .attr('width', width)
  .attr('class', 'curtain')
  .attr('transform', 'rotate(180)')
  .style('fill', '#ffffff')

/* Optionally add a guideline */
var guideline = chart1.append('line')
  .attr('stroke', '#333')
  .attr('stroke-width', 0.4)
  .attr('class', 'guide')
  .attr('x1', 1)
  .attr('y1', 1)
  .attr('x2', 1)
  .attr('y2', height)

var t = chart1.transition()
  .delay(120)
  .duration(500)
  .ease('linear')
  .each('end', function() {
    d3.select('line.guide')
      .transition()
      .style('opacity', 0)
      .remove()
  });

t.select('rect.curtain')
  .attr('width', 0);
t.select('line.guide')
  .attr('transform', 'translate(' + width + ', 0)')

d3.select("#show_guideline").on("change", function(e) {


});

Answer 1

只需在此处删除 interpolate 函数：

var valueline = d3.svg.line()
    .interpolate("basis")
    .x(function(d) {
        return x(d.date);
    })
    .y(function(d) {
        return y(d.XMAS);
    });

在valueline2 中执行相同的操作。现在你正在使用basis，它会创建一个B-spline。

如果您想设置不同的插值，here is a list D3 v3.x 中的可用选项。

这是你更新的小提琴：https://jsfiddle.net/7apnhbqd/

Answer 2

如果您不希望 d3 平滑边缘，则应从线生成器中删除插值。

https://jsfiddle.net/cexLbfnk/3/

var valueline2 = d3.svg.line()
  .interpolate("basis") // this line needs to go
  .x(function(d) {
    return x(d.date);
  })
  .y(function(d) {
    return y(d.JANSALES);
  });