嗨，我这里有一个热图，我正在尝试为其着色。现在它全部都是红色的，但我想使用 d3.interpolateRdYlBu，我希望我的值较低的是蓝色，较高的是红色，所以我希望它能很好地胶凝。我知道它的读数正确，因为我在控制台中看到红色并且没有其他错误，但我没有做正确的事情，它没有考虑我的值(value)并相应地做。任何帮助将不胜感激!
<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<!-- Load color palettes -->
<script src="https://d3js.org/d3-scale-chromatic.v1.min.js"></script>
<script>
// set the dimensions and margins of the graph
var margin = {top: 80, right: 25, bottom: 30, left: 40},
width = 1000 - margin.left - margin.right,
height = 1000 - margin.top - margin.bottom;
// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
.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 + ")");
//Read the data
d3.csv("https://raw.githubusercontent.com/Nataliemcg18/Data/master/NASA_Surface_Temperature.csv", function(data) {
// Labels of row and columns -> unique identifier of the column called 'group' and 'variable'
var myGroups = d3.map(data, function(d){return d.group;}).keys()
var myVars = d3.map(data, function(d){return d.variable;}).keys()
// Build X scales and axis:
var x = d3.scaleBand()
.range([ 0, width ])
.domain(myGroups)
.padding(0.05);
svg.append("g")
.style("font-size", 15)
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x).tickSize(0))
.select(".domain").remove()
// Build Y scales and axis:
var y = d3.scaleBand()
.range([ height, 0 ])
.domain(myVars)
.padding(0.05);
svg.append("g")
.style("font-size", 15)
.call(d3.axisLeft(y).tickSize(0))
.select(".domain").remove()
// Build color scale
var myColor = d3.scaleSequential()
.interpolator( d3.interpolateRdYlBu)
.domain([1,100])
// create a tooltip
var tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "2px")
.style("border-radius", "5px")
.style("padding", "5px")
// Three function that change the tooltip when user hover / move / leave a cell
var mouseover = function(d) {
tooltip
.style("opacity", 1)
d3.select(this)
.style("stroke", "green")
.style("opacity", 1)
}
var mousemove = function(d) {
tooltip
.html("The exact value of this cell is: " + d.value, )
.style("left", (d3.mouse(this)[0]+70) + "px")
.style("top", (d3.mouse(this)[1]) + "px")
}
var mouseleave = function(d) {
tooltip
.style("opacity", 0)
d3.select(this)
.style("stroke", "none")
.style("opacity", 0.8)
}
// add the squares
svg.selectAll()
.data(data, function(d) {return d.group+':'+d.variable;})
.enter()
.append("rect")
.attr("x", function(d) { return x(d.group) })
.attr("y", function(d) { return y(d.variable) })
.attr("rx", 4)
.attr("ry", 4)
.attr("width", x.bandwidth() )
.attr("height", y.bandwidth() )
.style("fill", function(d) { return myColor(d.value)} )
.style("stroke-width", 4)
.style("stroke", "none")
.style("opacity", 0.8)
.on("mouseover", mouseover)
.on("mousemove", mousemove)
.on("mouseleave", mouseleave)
})
// Add title to graph
svg.append("text")
.attr("x", 0)
.attr("y", -50)
.attr("text-anchor", "left")
.style("font-size", "22px")
.text("A d3.js heatmap");
// Add subtitle to graph
svg.append("text")
.attr("x", 0)
.attr("y", -20)
.attr("text-anchor", "left")
.style("font-size", "14px")
.style("fill", "grey")
.style("max-width", 400)
.text("A short description of the take-away message of this chart.");
</script>
最佳答案
在您的色标中，您已将域设置为 [0,100]。然而，您的值在 0 到 1.5 之间，并且您希望将它们颠倒过来
所以，这应该可以解决这个问题:
// Build color scale
var myColor = d3.scaleSequential()
.interpolator( d3.interpolateRdYlBu)
.domain([1.3,0])
为了更彻底，您可以使用 d3.max 和 d3.min 函数来计算出最小值中的最大值:
var myColor = d3.scaleSequential()
.interpolator( d3.interpolateRdYlBu)
.domain([d3.max(data, d=>d.value),d3.min(data, d=>d.value)])
这是一个 jsFiddle 可以完成此操作:https://jsfiddle.net/x8zyud5t/
关于javascript - 使用 d3.js 创建热图，存在颜色问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/61512078/