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我有一个 D3 流量可视化，使用户能够在 9 个流域之间切换并查看原始流量数据、“高”和“低”流量事件（红点和黄点）以及高事件的估计阈值（红线）：

http://forestecoservices.net/FESTvisualizations/HubbardBrook/streamflow.html

数据源是一个 PostgreSQL 数据库，其数据采用此（相对标准）配置，此处显示为 csv：

日期,ws_1,ws_2,ws_3,ws_4,ws_5,ws_6,ws_7,ws_8,ws_9 1/1/2000,40,0.541,0.57,0.605,0.643,0.594,0.456,0.299,0.206 1/2/2000,0.739, 0.576,0.594,0.654,0.74,0.625,0.44,0.313,0.224

唯一的问题是我不知道如何将变量名输入 D3，.. 我找到了一些示例，但它们都以这种方式设置了数据：

日期、分水岭、价值

2000 年 1 月 1 日，ws_1, 40

2000 年 1 月 1 日，ws_2，0.541

等等

它可能不漂亮，但我知道我可以用 php 伪造它，所以我制作了一个组合框，它调用一个 php 脚本来查询数据库并吐出一个 json，然后 d3 使用它来重绘图形。（我还没有完全弄清楚如何让这些点也移动，但那是另一回事了）。我知道必须有一种（更好的）方法可以在 d3 中本地执行此操作，而无需求助于 php。

非常感谢任何建议！

史蒂夫·西格内尔

这是我的源代码：

<!DOCTYPE html>
<meta charset="utf-8">
<style>
body { font: 12px Arial;}

path {
stroke: steelblue;
stroke-width: 2;
fill: none;
}
.axis path,
.axis line {
fill: none;
stroke: grey;
stroke-width: 1;
shape-rendering: crispEdges;
}

.grid .tick {
stroke: lightgrey;
opacity: 0.9;
}
.grid path {
stroke-width: 0.1;
}

div.tooltip {
position: absolute;
text-align: center;
width: 80px;
height: 28px;
padding: 2px;
font: 11px sans-serif;
background: lightsteelblue;
border: 0px;
border-radius: 18px;
pointer-events: none;
}

</style>

<body>

<div id="option">
<select type='select' onchange='updateData(value);' style='color:red;font-size:1.3em;'>
   <option value='ws_1' name='ws_1' selected='true' >Watershed 1</option>
   <option value='ws_2' name='ws_2'>Watershed 2</option>
   <option value='ws_3' name='ws_3'>Watershed 3</option>
   <option value='ws_4' name='ws_4'>Watershed 4</option> 
   <option value='ws_5' name='ws_5'>Watershed 5</option>
   <option value='ws_6' name='ws_6'>Watershed 6</option>
   <option value='ws_7' name='ws_7'>Watershed 7</option> 
   <option value='ws_8' name='ws_8'>Watershed 8</option>
   <option value='ws_9' name='ws_9'>Watershed 9</option>
</select>
</div>

<script type="text/javascript" src="http://d3js.org/d3.v3.min.js"></script>
<script>

var margin = {top: 30, right: 20, bottom: 30, left: 50},
    width =800 - margin.left - margin.right,
    height = 420 - margin.top - margin.bottom;

var parseDate = d3.time.format("%Y-%m-%d").parse;
var formatTime = d3.time.format("%e %b %Y");

var x = d3.time.scale().range([0, width]);

var y = d3.scale.linear().range([height, 0]);

var xAxis = d3.svg.axis().scale(x)
    .orient("bottom").ticks(10);

var yAxis = d3.svg.axis().scale(y)
    .orient("left").ticks(5);

//create line of stream flow values
var valueline = d3.svg.line()
    //.interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.flow); });

//create line for hi events threshold
var hithreshold = d3.svg.line() 
    //.interpolate("monotone")
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(17.11891); }); 

var tooltipdiv = d3.select("body")  //div for tooltips
    .append("div")
    .attr("class", "tooltip")
    .style("opacity", 0);

var svg = d3.select("body") //set up svg
    .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 + ")");

//Set up Grid Lines
function make_x_axis() {
return d3.svg.axis()
.scale(x)
.orient("bottom")
.ticks(10)
}
function make_y_axis() {
return d3.svg.axis()
.scale(y)
.orient("left")
.ticks(5)
}



// Get the data
d3.json("data/streamflow_json.php?watershed=ws_1", function(error, data)    
        {
        data.forEach(function(d) 
            {
            d.date = parseDate(d.date);
            d.flow = +d.flow;
            });

        // Scale the range of the data
        x.domain(d3.extent(data, function(d) { return d.date; }));
        y.domain([0, d3.max(data, function(d) { return d.flow; })]);

        svg.append("g")  //grid for x axis
            .attr("class", "grid")
            .attr("transform", "translate(0," + height + ")")
            .call(make_x_axis()
                .tickSize(-height, 0, 0)
                .tickFormat("")
                )

        svg.append("g")  //grid for y axis
        .attr("class", "grid")
        .call(make_y_axis()
            .tickSize(-width, 0, 0)
            .tickFormat("")
            )

        svg.append("path") // Add the valueline path.
            .attr("d", valueline(data))
            .attr("class", "line");
        
        svg.append("path") // Add the hi threshold path.
            .attr("class", "hiline")
            .style("stroke", "red")
            .attr("d", hithreshold(data));

        svg.append("text")  // Chart Title
            .attr("x", (width / 2))
            .attr("y", 0 - (margin.top / 2))
            .attr("text-anchor", "middle")
            .style("font-size", "16px")
            .style("text-decoration", "underline")
            .text("Hubbard Brook Stream Flow");

        svg.append("g") // Add the X Axis
            .attr("class", "x axis")
            .attr("transform", "translate(0," + height + ")")
            .call(xAxis);
        
        svg.append("text") // text label for the x axis
            .attr("x", width / 2 )
            .attr("y", height + margin.bottom)
            .style("text-anchor", "middle")
            .text("Date");
        
        svg.append("g") // Add the Y Axis
            .attr("class", "y axis")
            .call(yAxis);
        
        svg.append("text")   // text for Y axis
            .attr("transform", "rotate(-90)")
            .attr("y", 0 - margin.left)
            .attr("x", 0 - (height / 2))
            .attr("dy", "1em")
            .style("text-anchor", "middle")
            .text("Stream Flow (mm)");

        svg.selectAll("circle")  // add value dots, sized & colored
            .data(data)
            .enter().append("circle")
            //.attr("class", "dot")
            .attr("r", function(d) {
                if (d.flow > 17.11891) {return 3} 
                else if (d.flow < 0.01) { return 3 } 
                else {return 1} 
                ;}) 
            .style("fill", function(d) { 
                if (d.flow > 17.11891) {return "red"} 
                if (d.flow < 0.01) {return "yellow"} 
                else { return "black" } 
                ;}) 
            //.attr("d", tooltipdot(data))
            .attr("cx", function(d) { return x(d.date); })
            .attr("cy", function(d) { return y(d.flow); })
            .on("mouseover", function(d) {
                tooltipdiv.transition()
                .duration(200)
                .style("opacity", .9);
                tooltipdiv.html(formatTime(d.date) + "<br/>" + d.flow)
                .style("left", (d3.event.pageX) + "px")
                .style("top", (d3.event.pageY - 28) + "px");
                })
            .on("mouseout", function(d) {
                tooltipdiv.transition()
                .duration(500)
                .style("opacity", 0);
                });
});

function updateData(value) {
//Get the data again
    d3.json("data/streamflow_json.php?watershed="+value, function(error, data)  
        {
        data.forEach(function(d) 
            {
            d.date = parseDate(d.date);
            d.flow = +d.flow;
            });
    
        // Scale the range of the data again
        x.domain(d3.extent(data, function(d) { return d.date; }));
        y.domain([0, d3.max(data, function(d) { return d.flow; })]);

        // Select the section we want to apply our changes to
        var svg = d3.select("body").transition();
        // Make the changes
        svg.select(".line") // change the value line
            .duration(1750)
            .attr("d", valueline(data));
        svg.select(".hiline") // change the hithreshold line
            .duration(2750)
            .attr("d", hithreshold(data));
        /*svg.select(".circle") // change the dot
            .duration(750)
            .attr("d", tooltipdot(data));*/
        svg.select(".x.axis") // change the x axis
            .duration(2750)
            .call(xAxis);
        svg.select(".y.axis") // change the y axis
            .duration(2750)
            .call(yAxis);
        });
    };

</script>
</body>
4

1 回答 1

0

d3 可以处理原始 csv 而无需任何服务器端格式化：

//global variable to hold data
var csv;

// Get the data
d3.csv("data/streamflow_json.php?watershed", function(error, result){
        csv = result;
        var data = [];
        csv.forEach(function(d){
            data.push({flow: +d['ws_1'], date: parseDate(d.date)});
         });

         //ect
});

由于数据存储在 csv 变量中，我们可以使用它而无需再次查询服务器：

function updateData(value) {
        var data = [];
        csv.forEach(function(d){
            data.push({flow: +d[value], date: parseDate(d.date)});
         });

         //ect
}
于 2013-04-27T00:21:30.143 回答