d3.js: how to conditionally render a curve? - javascript

I've got a function that draws a curve through dots I give as argument, as follows:
var data = [
// stage 1-9, intensity %, draw disk
{x:1, y: 0, point:true},
{x:4, y: 30, point:true},
{x:5, y: 70, point:true},
{x:6, y:100, point:true},
{x:7, y: 90, point:true},
{x:8, y: 40, point:true},
{x:9, y: 10, point:false}
];
I'd like to handle the point members that tells whether or not to draw an additional spot.
How to do that?
The function that draws the curve as it is per today:
function curveChart(data) {
for (i in data) {
data[i].y = 5.5*data[i].y/100; // normalize
data[i].id = i;
}
var margin = {top: 10, right: 190, bottom: 275, left: 35},
width = 915 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var x = d3.scale.linear() //.time.scale()
.domain([1, 9]) // 9 stages
.range([0, width]);
var y = d3.scale.linear()
.domain([0, 6])
.range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var line = d3.svg.line()
.interpolate("monotone")
.x(function(d) { return x(d.x); })
.y(function(d) { return y(d.y); });
var svg = d3.select(".curveChart").append("svg")
.datum(data)
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
svg.append("path")
.attr("class", "line")
.attr("d", line);
var n = 1;
svg.selectAll("circle")
.data(data)
.enter()
.append("circle")
.attr("class", "dot")
.attr("cx", line.x())
.attr("cy", line.y())
.attr("r", 2)
.attr("bubbleid", function(d){return d.id; })
.transition(1000)
.duration(800)
.attr("r", 10);
svg.selectAll("circle").on("click", function(){
d3.selectAll(".active").classed("active", false);
d3.select(this).classed("active", true);
var id = $(this).attr('bubbleid');
console.log("clicked on "+$(this).attr('bubbleid'));
$(".bubble").removeClass("show");
$("#bubble"+id).addClass("show");
d3.select(this)
.transition()
.duration(400)
.attr('r', 25)
.transition()
.duration(400)
.attr('r', 10)
;
});
}
The fiddle : http://jsfiddle.net/stephanedeluca/R44cB/

The easiest way to do this is to filter the data before passing it to .data(), retaining only the elements where point is true:
svg.selectAll("circle")
.data(data.filter(function(d) { return d.point; }))
Complete demo here.

Related

wrong date printing on x axis of line graph in d3 with extra tick

i am using D3 to draw line graph in JavaScript. Line of Line graph is drawn right but date on x axis is not correct and it is also showing one extra tick on x axis. I had also tried changing tick format but i failed. I don't know where i am doing wrong. please help. here is my code
var margin = {top: 50, right: 50, bottom: 50, left: 50}
, width = window.innerWidth - margin.left - margin.right // Use the window's width
, height = window.innerHeight - margin.top - margin.bottom; // Use the window's height
// The number of datapoints
var n = 4;
var xScale = d3.scaleLinear()
.domain([0, n-1]) // input
.range([0, width]); // output
var parseTime = d3.timeParse("%d-%b-%y");
// 6. Y scale will use the randomly generate number
var yScale = d3.scaleLinear()
.domain([0, 100]) // input
.range([height, 0]); // output
d3.csv("Data_vis.csv", function(data){
//console.log(data);
var nov_11_percent= 22;
var oct_16_percent= 25;
var nov_13_percent= 24;
var oct_22_percent= 21;
var dataset2=[{"date":'2018-09-11', "value": nov_11_percent},
{"date":'2018-10-16', "value": oct_16_percent},
{"date":'2018-10-22', "value": oct_22_percent},
{"date":'2018-11-13', "value": nov_13_percent}];
dataset2.forEach(function(d) {
d.date = new Date(d.date);
});
var line = d3.line()
.x(function(d, i) {
//alert(parseTime(d.date));
return xScale(d.date);
})
.y(function(d,i ) {
return yScale(d.value);
})
.curve(d3.curveMonotoneX)
xScale.domain(d3.extent(dataset2, function(d) {
return d.date; }));
yScale.domain([0, d3.max(dataset2, function(d) {
return d.value;
})]);
var svg = d3.select("body").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 + ")");
svg.append("g")
.attr("class", "axis")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(xScale)
.ticks(4)
.tickFormat(d3.timeFormat("%Y-%m-%d")));
svg.append("g")
.attr("class", "y axis")
.call(d3.axisLeft(yScale));
svg.append("path")
.datum(dataset2)
.attr("class", "line")
.attr("d", line);
svg.selectAll(".dot")
.data(dataset2)
.enter().append("circle") // Uses the enter().append() method
.attr("class", "dot") // Assign a class for styling
.attr("cx", function(d) { return xScale(d.date) })
.attr("cy", function(d) { return yScale(d.value) })
.attr("r", 10);
});
any help would be much appreciated. thank you
Use a point scale instead of a linear scale for x.
var xScale = d3
.scalePoint()
.range([0, width])
.domain(dataset2.map(i => i.date))
const margin = { top: 50, right: 50, bottom: 50, left: 50 }
const width = window.innerWidth - margin.left - margin.right // Use the window's width
const height = window.innerHeight - margin.top - margin.bottom // Use the window's height
const dataset2 = [{ date: "2018-09-11", value: 22 },{ date: "2018-10-16", value: 25 },{ date: "2018-10-22", value: 24 },{ date: "2018-11-13", value: 21 }]
dataset2.forEach(function(d) {
d.date = new Date(d.date)
})
// 6. Y scale will use the randomly generate number
const yScale = d3
.scaleLinear()
.domain([
0,
d3.max(dataset2, function(d) {
return d.value
})
]) // input
.range([height, 0]) // output
const xScale = d3
.scalePoint()
.range([0, width])
.domain(dataset2.map(d => d.date))
const line = d3
.line()
.x(function(d, i) {
return xScale(d.date)
})
.y(function(d, i) {
return yScale(d.value)
})
.curve(d3.curveMonotoneX)
const svg = d3
.select("body")
.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 + ")")
svg
.append("g")
.attr("class", "axis")
.attr("transform", "translate(0," + height + ")")
.call(
d3
.axisBottom(xScale)
.tickFormat(d3.timeFormat("%m/%d"))
)
svg
.append("g")
.attr("class", "y axis")
.call(d3.axisLeft(yScale))
svg
.append("path")
.datum(dataset2)
.attr("class", "line")
.attr("d", line)
.attr("fill", "none")
.attr("stroke", "black")
svg
.selectAll(".dot")
.data(dataset2)
.enter()
.append("circle") // Uses the enter().append() method
.attr("class", "dot") // Assign a class for styling
.attr("cx", function(d) {
return xScale(d.date)
})
.attr("cy", function(d) {
return yScale(d.value)
})
.attr("r", 10)
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
Codepen

Adding Clipping path is hidding my y-axis in D3 graph

I am trying to create a D3 scatter Plot graph with Zooming facility. While zooming , I want to hide all the data points that goes beyond both the axis. For that I am using clipping Path. However, Using it, hides all the ticks and values on the y-axis. Just the line remains visible.
Here is my code in angular 4 :
import { Component, OnInit, Input, ViewChild, ElementRef } from '#angular/core';
import * as d3 from 'd3';
#Component({
selector: 'app-scatterplot',
templateUrl: './scatterplot.component.html',
styleUrls: ['./scatterplot.component.css']
})
export class ScatterplotComponent implements OnInit {
#ViewChild('chart1') private chartContainer: ElementRef;
dataValue = [{ x: "67", y: "188", },
{ x: "200", y: "163" },
{ x: "254", y: "241" },
{ x: "175", y: "241" },
];
ngOnInit() {
this.graph();
}
graph() {
const element = this.chartContainer.nativeElement;
var svgWidth = 400;
var svgHeight = 400;
var margin = { top: 30, right: 40, bottom: 50, left: 60 };
var width = svgWidth - margin.left - margin.right;
var height = svgHeight - margin.top - margin.bottom;
var originalCircle = {
"cx": -150,
"cy": -15,
"r": 20
};
var svgViewport = d3.select(element)
.append('svg')
.attr('width', svgWidth)
.attr('height', svgHeight)
// clipping path
svgViewport.append("clipPath")
.attr("id", "clip")
.append("rect")
.attr("width", svgWidth)
.attr("height", svgHeight)
.attr("fill", "red")
.attr("fill-opacity", 0.1);
// create scale objects
var x = d3.scaleLinear()
.domain([1, 500])
.range([0, width]);
var y = d3.scaleLinear()
.domain([1, 500])
.range([height, 0]);
// create axis objects
var xAxis = d3.axisBottom(x);
var yAxis = d3.axisLeft(y);
// Zoom Function
var zoom = d3.zoom()
.on("zoom", zoomFunction);
// Inner Drawing Space
var innerSpace = svgViewport.append("g")
.attr("class", "inner_space")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
.attr("clip-path", "url(#clip)")
.call(zoom);
// append some dummy data
var data = innerSpace.selectAll("circle")
.data(this.dataValue)
.enter().append("circle")
.attr("class", "dot")
.attr("cx", function (d) {
return x(d.x)
;
})
.attr("cy", function (d) {
return y(d.y);
})
.attr("r", 2);
// Draw Axis
var gX = innerSpace.append("g")
.attr("class", "axis")
.attr("transform", "translate(0, " + height + ")")
.call(xAxis);
var gY = innerSpace.append("g")
.attr("class", "axis axis--y")
.call(yAxis);
// append zoom area
var view = innerSpace.append("rect")
.attr("class", "zoom")
.attr("width", width)
.attr("height", height - 10)
.attr("fill", "transparent")
.attr("fill-opacity", 0.1)
.call(zoom)
function zoomFunction() {
// create new scale ojects based on event
var new_xScale = d3.event.transform.rescaleX(x)
var new_yScale = d3.event.transform.rescaleY(y)
console.log(d3.event.transform)
// update axes
gX.call(xAxis.scale(new_xScale));
gY.call(yAxis.scale(new_yScale));
// update circle
data.attr("transform", d3.event.transform)
};
}
}
From the above code , if I remove the code
.attr("clip-path", "url(#clip)")
from the code block:
// Inner Drawing Space
var innerSpace = svgViewport.append("g")
.attr("class", "inner_space")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
.attr("clip-path", "url(#clip)")
.call(zoom);
than the graph is comming perfect. But on zooming the data values keep appearing even if it goes beyond both axis lines. How do I hide it.

D3.JS: Making plotted line static wrt axis in a 2D plot

I am beginner in D3 and don't know a lot about it.
I am currently trying to plot a 2D line on a graph using D3. I have been successfully able to plot the line, add axis , and even add zoom capabilities to the plot.
I am stuck in making the line hinged to y axis such that you can't just click on it and move it left or right (Currently if you would run the jsfiddle you could click on it and move the plotted line). I would still want to zoom in or out . But it should remain hinged to the y axis. Please let me know if this clarifies my issue.
Thanks!
Link to JS fiddle:
https://jsfiddle.net/adityap16/4sts8nfs/2/
Code
var data = [{
"mytime": "2015-12-01T23:10:00.000Z",
"value": 64
}, {
"mytime": "2015-12-01T23:15:00.000Z",
"value": 67
}, {
"mytime": "2015-12-01T23:20:00.000Z",
"value": 70
}, {
"mytime": "2015-12-01T23:25:00.000Z",
"value": 64
}, {
"mytime": "2015-12-01T23:30:00.000Z",
"value": 72
}, {
"mytime": "2015-12-01T23:35:00.000Z",
"value": 75
}, {
"mytime": "2015-12-01T23:40:00.000Z",
"value": 71
}, {
"mytime": "2015-12-01T23:45:00.000Z",
"value": 80
}, {
"mytime": "2015-12-01T23:50:00.000Z",
"value": 83
}, {
"mytime": "2015-12-01T23:55:00.000Z",
"value": 86
}, {
"mytime": "2015-12-02T00:00:00.000Z",
"value": 80
}, {
"mytime": "2015-12-02T00:05:00.000Z",
"value": 85
}];
var parseDate = d3.time.format("%Y-%m-%dT%H:%M:%S.%LZ").parse;
data.forEach(function(d) {
d.mytime = parseDate(d.mytime);
});
//var margin = { top: 30, right: 30, bottom: 40, left:50 },
var margin = {
top: 30,
right: 30,
bottom: 40,
left: 50
},
height = 200,
width = 900;
var color = "green";
var xaxis_param = "mytime";
var yaxis_param = "value";
var params1 = {
margin: margin,
height: height,
width: width,
color: color,
xaxis_param: xaxis_param,
yaxis_param: yaxis_param
};
draw_graph(data, params1);
function draw_graph(data, params) {
var make_x_axis = function() {
return d3.svg.axis()
.scale(x_scale)
.orient("bottom")
.ticks(5);
};
var make_y_axis = function() {
return d3.svg.axis()
.scale(y_scale)
.orient("left")
.ticks(5);
};
//Get the margin
var xaxis_param = params.xaxis_param;
var yaxis_param = params.yaxis_param;
var color_code = params.color;
var margin = params.margin;
var height = params.height - margin.top - margin.bottom,
width = params.width - margin.left - margin.right;
var x_extent = d3.extent(data, function(d) {
return d[xaxis_param]
});
var y_extent = d3.extent(data, function(d) {
return d[yaxis_param]
});
var x_scale = d3.time.scale()
.domain(x_extent)
.range([0, width]);
var y_scale = d3.scale.linear()
.domain([0, y_extent[1]])
.range([height, 0]);
var zoom = d3.behavior.zoom()
.x(x_scale)
.y(y_scale)
.on("zoom", zoomed);
//Line
var line = d3.svg.line()
.defined(function(d) {
return d[yaxis_param];
})
.x(function(d) {
return x_scale(d[xaxis_param]);
})
.y(function(d) {
return y_scale(d[yaxis_param]);
});
var lineRef = d3.svg.line()
.x(function(d) {
return x_scale(d[xaxis_param]);
})
.y(function(d) {
return y_scale(20);
});
var myChart = d3.select('body').append('svg')
.attr('id', 'graph')
.style('background', '#E7E0CB')
.attr('width', width + margin.left + margin.right)
.attr('height', height + margin.top + margin.bottom)
.append('g')
.attr('transform', 'translate(' + margin.left + ', ' + margin.top + ')')
.call(zoom);
myChart.append("svg:rect")
.attr("width", width)
.attr("height", height)
.attr("class", "plot");
var legend = myChart.append("g")
.attr("class", "legend")
.attr("transform", "translate(" + 5 + "," + (height - 25) + ")")
legend.append("rect")
.style("fill", color_code)
.attr("width", 20)
.attr("height", 20);
legend.append("text")
.text(yaxis_param)
.attr("x", 25)
.attr("y", 12);
var vAxis = d3.svg.axis()
.scale(y_scale)
.orient('left')
.ticks(5)
var hAxis = d3.svg.axis()
.scale(x_scale)
.orient('bottom')
.ticks(5);
var majorAxis = d3.svg.axis()
.scale(x_scale)
.orient('bottom')
.ticks(d3.time.day, 1)
.tickSize(-height)
.outerTickSize(0);
myChart.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(hAxis);
myChart.append("g")
.attr("class", "x axis major")
.attr("transform", "translate(0," + height + ")")
.call(majorAxis);
myChart.append("g")
.attr("class", "y axis")
.call(vAxis);
var circlePoint = myChart.selectAll('circle')
.data(data)
.enter()
.append("circle");
var circleAttributes = circlePoint
.attr("cx", function (d) { return x_scale(d[xaxis_param]); })
.attr("cy", function (d) { return y_scale(d[yaxis_param]); })
.attr("r", 3)
.style("fill", "none")
.style("stroke", "red");
var clip = myChart.append("svg:clipPath")
.attr("id", "clip")
.append("svg:rect")
.attr("x", 0)
.attr("y", 0)
.attr("width", width)
.attr("height", height);
var chartBody = myChart.append("g")
.attr("clip-path", "url(#clip)");
chartBody.append("svg:path")
.datum(data)
.attr('class', 'line')
.attr("d", line)
.attr('stroke', color_code)
.attr('stroke-width', 1)
.attr('fill', 'none');
chartBody
.append('svg:path')
.datum(data)
.attr('class', 'line1')
.attr("d", lineRef)
.attr('stroke', 'blue')
.attr('stroke-width', 1)
.style("stroke-dasharray", ("3, 3"))
.attr('fill', 'none');
function zoomed() {
myChart.select(".x.axis").call(hAxis);
myChart.select(".y.axis").call(vAxis);
myChart.select(".x.axis.major").call(majorAxis);
myChart.select(".line")
.attr("class", "line")
.attr("d", line);
myChart.select(".line1")
.attr("class", "line1")
.attr("d", lineRef);
}
}
Add this .on("mousedown.zoom", null) to disable panning:
var myChart = d3.select('body').append('svg')
.attr('id', 'graph')
.style('background', '#E7E0CB')
.attr('width', width + margin.left + margin.right)
.attr('height', height + margin.top + margin.bottom)
.append('g')
.attr('transform', 'translate(' + margin.left + ', ' + margin.top + ')')
.call(zoom)
.on("mousedown.zoom", null);//disable panning
working code here

How to create vertically grouped bar chart in d3.js using json data?

In a web application I was supposed to create a vertically grouped bar chart using d3.js using json data. Previously I create a horizontal grouped bar using the following code. Can anyone help me out? Thanks in advance.
var data = {
labels: [
'resilience', 'maintainability', 'accessibility',
'uptime', 'functionality', 'impact'
],
series: [
{
label: '2012',
values: [4, 8, 15, 16, 23, 42]
},
{
label: '2013',
values: [12, 43, 22, 11, 73, 25]
},
{
label: '2014',
values: [31, 28, 14, 8, 15, 21]
},]
};
var chartWidth = 300,
barHeight = 20,
groupHeight = barHeight * data.series.length,
gapBetweenGroups = 10,
spaceForLabels = 150,
spaceForLegend = 150;
// Zip the series data together (first values, second values, etc.)
var zippedData = [];
for (var i=0; i<data.labels.length; i++) {
for (var j=0; j<data.series.length; j++) {
zippedData.push(data.series[j].values[i]);
}
}
// Color scale
var color = d3.scale.category20();
var chartHeight = barHeight * zippedData.length + gapBetweenGroups * data.labels.length;
var x = d3.scale.linear()
.domain([0, d3.max(zippedData)])
.range([0, chartWidth]);
var y = d3.scale.linear()
.range([chartHeight + gapBetweenGroups, 0]);
var yAxis = d3.svg.axis()
.scale(y)
.tickFormat('')
.tickSize(0)
.orient("left");
// Specify the chart area and dimensions
var chart = d3.select(".chart")
.attr("width", spaceForLabels + chartWidth + spaceForLegend)
.attr("height", chartHeight);
// Create bars
var bar = chart.selectAll("g")
.data(zippedData)
.enter().append("g")
.attr("transform", function(d, i) {
return "translate(" + spaceForLabels + "," + (i * barHeight + gapBetweenGroups * (0.5 + Math.floor(i/data.series.length))) + ")";
});
// Create rectangles of the correct width
bar.append("rect")
.attr("fill", function(d,i) { return color(i % data.series.length); })
.attr("class", "bar")
.attr("width", x)
.attr("height", barHeight - 1);
// Add text label in bar
bar.append("text")
.attr("x", function(d) { return x(d) - 3; })
.attr("y", barHeight / 2)
.attr("fill", "red")
.attr("dy", ".35em")
.text(function(d) { return d; });
// Draw labels
bar.append("text")
.attr("class", "label")
.attr("x", function(d) { return - 10; })
.attr("y", groupHeight / 2)
.attr("dy", ".35em")
.text(function(d,i) {
if (i % data.series.length === 0)
return data.labels[Math.floor(i/data.series.length)];
else
return ""});
chart.append("g")
.attr("class", "y axis")
.attr("transform", "translate(" + spaceForLabels + ", " + -gapBetweenGroups/2 + ")")
.call(yAxis);
// Draw legend
var legendRectSize = 18,
legendSpacing = 4;
var legend = chart.selectAll('.legend')
.data(data.series)
.enter()
.append('g')
.attr('transform', function (d, i) {
var height = legendRectSize + legendSpacing;
var offset = -gapBetweenGroups/2;
var horz = spaceForLabels + chartWidth + 40 - legendRectSize;
var vert = i * height - offset;
return 'translate(' + horz + ',' + vert + ')';
});
legend.append('rect')
.attr('width', legendRectSize)
.attr('height', legendRectSize)
.style('fill', function (d, i) { return color(i); })
.style('stroke', function (d, i) { return color(i); });
legend.append('text')
.attr('class', 'legend')
.attr('x', legendRectSize + legendSpacing)
.attr('y', legendRectSize - legendSpacing)
.text(function (d) { return d.label; });
After continuous digging I found the correct way of doing this. Thanks to Mike Bostock for the example he provided in here. In here you can also find out the elaborate discussion of that example. Thanks for your support :)
var margin = {top: 20, right: 20, bottom: 30, left: 40},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var x0 = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var x1 = d3.scale.ordinal();
var y = d3.scale.linear()
.range([height, 0]);
var color = d3.scale.ordinal()
.range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);
var xAxis = d3.svg.axis()
.scale(x0)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickFormat(d3.format(".2s"));
//console.log(margin.left);
var svg = d3.select("body").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 + ")");
/*Our json object is [{letter: "A", frequency: .08167,depth:.32},{letter: "B", frequency: .01492,depth:.69}]
To use csv file you just need to follow the link I provided
*/
var data = [
{letter: "A", frequency: .08167,depth:.32},
{letter: "B", frequency: .01492,depth:.69}
];
var groupNames=d3.keys(data[0]).filter(function(key){return key!="letter";})
data.forEach(function(d){
d.groups=groupNames.map(function(name){return {name:name,value:+d[name]};})
});
x0.domain(data.map(function(d){return d.letter;}));
x1.domain(groupNames).rangeRoundBands([0, x0.rangeBand()]);
y.domain([0,d3.max(data,function(d){
return d3.max(d.groups,function(d){
return d.value;
});
})]);
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Letter Fun");
var state = svg.selectAll(".state")
.data(data)
.enter().append("g")
.attr("class", "g")
.attr("transform", function(d) { return "translate(" + x0(d.letter) + ",0)"; });
state.selectAll("rect")
.data(function(d) { return d.groups; })
.enter().append("rect")
.attr("width", x1.rangeBand())
.attr("x", function(d) { return x1(d.name); })
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return height - y(d.value); })
.style("fill", function(d) { return color(d.name); });
Please let me know if you have anything to know about the code.

d3.js histogram with positive and negative values

I can't figure out how to properly create a histogram where there are both positive and negative values in the data array.
I've used the histogram example here http://bl.ocks.org/mbostock/3048450 as a base, and while the x axis values and ticks are correct, the bars are out to lunch.
Data
var values = [-15, -20, -22, -18, 2, 6, -26, -18, -15, -20, -22, -18, 2, 6, -26, -18];
X Scale
var x0 = Math.max(-d3.min(values), d3.max(values));
var x = d3.scale.linear()
.domain([-x0, x0])
.range([0, width])
.nice();
Check the jfiddle here: http://jsfiddle.net/tNdJj/2/
I assume it's something missing from the "rect" creations but I am not seeing it.
Using the example of histogram from the following question: Bar chart with negative values
I inversed x and y and adapted the display. Now you have a nice basis.
Here is the corresponding jsFiddle: http://jsfiddle.net/chrisJamesC/tNdJj/4/
Here is the relevant code:
var data = [-15, -20, -22, -18, 2, 6, -26, -18];
var margin = {top: 30, right: 10, bottom: 10, left: 30},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var y0 = Math.max(Math.abs(d3.min(data)), Math.abs(d3.max(data)));
var y = d3.scale.linear()
.domain([-y0, y0])
.range([height,0])
.nice();
var x = d3.scale.ordinal()
.domain(d3.range(data.length))
.rangeRoundBands([0, width], .2);
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var svg = d3.select("body").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 + ")");
svg.selectAll(".bar")
.data(data)
.enter().append("rect")
.attr("class", function(d) { return d < 0 ? "bar negative" : "bar positive"; })
.attr("y", function(d) { return y(Math.max(0, d)); })
.attr("x", function(d, i) { return x(i); })
.attr("height", function(d) { return Math.abs(y(d) - y(0)); })
.attr("width", x.rangeBand());
svg.append("g")
.attr("class", "x axis")
.call(yAxis);
svg.append("g")
.attr("class", "y axis")
.append("line")
.attr("y1", y(0))
.attr("y2", y(0))
.attr("x1", 0)
.attr("x2", width);
Note: For simple visualizations like this, I would recommand using nvd3.js
The trick is that the demo code is overly optimistic, assuming that its input is positive:
bar.append("rect")
.attr("x", 1)
// .attr("width", x(data[0].dx) - 1) // Does the wrong thing for negative buckets.
.attr("width", x(data[0].x + data[0].dx) - 1)
.attr("height", function(d) { return height - y(d.y); });
http://jsfiddle.net/tNdJj/46/

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