Develop Reference

D3 plotting categorical data with a range(min, max) value using points and line

I have a dataset that has 3 fields a name, a min value (value2) and a max value (value) that represent a range.
//The data
var data =[{"name": 'Scotty', "value2":0, "value":17},
{"name":'Dick', "value2":10, "value":17},
{"name":'James', "value2":5, "value":null},
{"name":'Max', "value2":2, "value":9}]
Currently I have it represented with a bar chart using this code that works ok except in cases where the points value2 and value are very close or there is a null value.
//Chart size parameters
var margin = {top: 20, right: 30, bottom: 90, left: 40},
width = 830 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
//Chart axis
var x = d3.scaleBand()
.domain(data.map(function(d) { return d.name; }))
.range([2, width])
.scaleBand(0.10);
var y = d3.scaleLinear()
.domain([0, d3.max(data, function(d) { return d.value; })])
.range([height, 0]);
var xAxis = d3.axisBottom(x);
var yAxis = d3.axisLeft(y);
//Initialize chart
var chart = d3.select("#mychart").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 + ")");
//Adding both axis
chart.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
chart.append("g")
.attr("class", "y axis")
.call(yAxis);
//Where the box is drawn
chart.selectAll(".box")
.data(data)
.enter().append("rect")
.attr("class", "box")
.attr("x", function(d) { return x(d.name); })
.attr("y", function(d) { return y(d.value); })
.attr("height", function(d) { return y(d.value2) - y(d.value); }) //Plot range
.attr("width", x.bandwidth()); //spacing for bars
Is there a way to plot the data with the following:
if two points are present plot both of them with a path connecting them
if one point is present with a null in field value only plot the one point

how do i clear my visualization in order to make space for the updated visualization using svg?

here's my d3.js function to visualize a bar graph:
function barGraph(data1)
{
// console(data1.count);
var i = 0;
data1.forEach(function(d){
while(i>0){
d.avspeed= +d.avspeed;
d.duration = +d.duration;
i--;
}
})
//console.log(data1.avspeed);
// console.log(data1.avspeed);
var margin = {top: 40, right: 20, bottom: 30, left: 40},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
//console.log(data1.avspeed);
console.log("hey1");
var formatPercent = d3.format("");
console.log("hey2");
var x = d3.scale.ordinal()
.rangeRoundBands([0, width], .1);
var y = d3.scale.linear()
.range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
console.log("hey");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickFormat(formatPercent);
console.log("hey3");
var tip = d3.tip()
.attr('class', 'd3-tip')
.offset([-10, 0])
.html(function(d) {
return "<strong>Avg Speed:</strong> <span style='color:red'>" + d.avspeed + "</span>";
})
var svg = d3.select("#rightside").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.call(tip);
console.log("heyllo ");
x.domain(data1.map(function(d) { return d.tripid; }));
y.domain([0, d3.max(data1, function(d) { return d.avspeed; })]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
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("Avg Speed");
svg.selectAll(".bar")
.data(data1)
.enter().append("rect")
.attr("class", "bar")
.attr("x", function(d) { return x(d.tripid); })
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.avspeed); })
.attr("height", function(d) { return height - y(d.avspeed); })
.on('mouseover', tip.show)
.on('mouseout', tip.hide)
console.log(d.avspeed);
console.log("hello234");
function type(d) {
d.avspeed = +d.avspeed;
return d;
}
}
It displays a graph based on the selected region on the map dynamically. If i select new region, another graph is being created below the old graph. I want the old graph to clear and new graph to be in place of old graph. How do I achieve that.
I am new to d3.js
Thanks in advance.

You can clear away anything inside of the parent container with .html("") while creating your svg:
var svg = d3.select("#rightside").html("").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 + ")");
remove also works but I prefer this slightly terser way of doing it.

Before appending the new avg, just call d3.select('svg').remove(); That will remove the first svg on the page (I'm assuming you only have one). If you don't have an svg, it won't fail, so you can always call it.

Unneeded white space before the 1st bar in D3 bar chart

I am trying to populate a data set into D3's Bar chart data. I am using this example from the d3: http://bl.ocks.org/mbostock/3885304
Here is my sample data:
var data = [{"name":"0","members_count":4},{"name":"1","members_count":1},{"name":"2","members_count":6},{"name":"3","members_count":1},{"name":"4","members_count":1},{"name":"5","members_count":2},{"name":"6","members_count":4},{"name":"7","members_count":3},{"name":"8","members_count":5},{"name":"9","members_count":1},{"name":"10","members_count":2},{"name":"11","members_count":3},{"name":"12","members_count":2},{"name":"13","members_count":0},{"name":"14","members_count":5},{"name":"15","members_count":2},{"name":"16","members_count":2},{"name":"17","members_count":4},{"name":"18","members_count":2},{"name":"19","members_count":4},{"name":"20","members_count":3},{"name":"21","members_count":5},{"name":"22","members_count":8},{"name":"23","members_count":3},{"name":"24","members_count":2},{"name":"25","members_count":3},{"name":"26","members_count":4},{"name":"27","members_count":4},{"name":"28","members_count":1},{"name":"29","members_count":1},{"name":"30","members_count":3},{"name":"31","members_count":5},{"name":"32","members_count":4},{"name":"33","members_count":3},{"name":"34","members_count":6},{"name":"35","members_count":2},{"name":"36","members_count":2},{"name":"37","members_count":7},{"name":"38","members_count":2},{"name":"39","members_count":4},{"name":"40","members_count":2},{"name":"41","members_count":1},{"name":"42","members_count":8},{"name":"43","members_count":10},{"name":"44","members_count":1},{"name":"45","members_count":5},{"name":"46","members_count":2},{"name":"47","members_count":5},{"name":"48","members_count":3},{"name":"49","members_count":1},{"name":"50","members_count":9},{"name":"51","members_count":3},{"name":"52","members_count":2},{"name":"53","members_count":8},{"name":"54","members_count":2},{"name":"55","members_count":3},{"name":"56","members_count":2},{"name":"57","members_count":2},{"name":"58","members_count":5},{"name":"59","members_count":1},{"name":"60","members_count":2},{"name":"61","members_count":4},{"name":"62","members_count":2},{"name":"63","members_count":2},{"name":"64","members_count":6},{"name":"65","members_count":6},{"name":"66","members_count":1},{"name":"67","members_count":1},{"name":"68","members_count":3},{"name":"69","members_count":5},{"name":"70","members_count":3},{"name":"71","members_count":4},{"name":"72","members_count":4},{"name":"73","members_count":1},{"name":"74","members_count":3},{"name":"75","members_count":2},{"name":"76","members_count":4},{"name":"77","members_count":5},{"name":"78","members_count":2},{"name":"79","members_count":1},{"name":"80","members_count":2},{"name":"81","members_count":1},{"name":"82","members_count":4},{"name":"83","members_count":3},{"name":"84","members_count":1},{"name":"85","members_count":4},{"name":"86","members_count":1},{"name":"87","members_count":3},{"name":"88","members_count":1},{"name":"89","members_count":8},{"name":"90","members_count":6},{"name":"91","members_count":6},{"name":"92","members_count":3},{"name":"93","members_count":4},{"name":"94","members_count":5},{"name":"95","members_count":2},{"name":"96","members_count":3},{"name":"97","members_count":2},{"name":"98","members_count":3},{"name":"99","members_count":6},{"name":"100","members_count":3},{"name":"101","members_count":1},{"name":"102","members_count":0},{"name":"103","members_count":5},{"name":"104","members_count":2},{"name":"105","members_count":1},{"name":"106","members_count":7},{"name":"107","members_count":1},{"name":"108","members_count":1},{"name":"109","members_count":7},{"name":"110","members_count":5},{"name":"111","members_count":5},{"name":"112","members_count":2},{"name":"113","members_count":6},{"name":"114","members_count":1},{"name":"115","members_count":2},{"name":"116","members_count":1},{"name":"117","members_count":1},{"name":"118","members_count":10},{"name":"119","members_count":2},{"name":"120","members_count":6},{"name":"121","members_count":1},{"name":"122","members_count":1},{"name":"123","members_count":2},{"name":"124","members_count":4},{"name":"125","members_count":5},{"name":"126","members_count":1},{"name":"127","members_count":1},{"name":"128","members_count":1},{"name":"129","members_count":3},{"name":"130","members_count":3},{"name":"131","members_count":3},{"name":"132","members_count":4},{"name":"133","members_count":3},{"name":"134","members_count":1},{"name":"135","members_count":5},{"name":"136","members_count":5},{"name":"137","members_count":1},{"name":"138","members_count":2},{"name":"139","members_count":5},{"name":"140","members_count":1},{"name":"141","members_count":1},{"name":"142","members_count":2},{"name":"143","members_count":2},{"name":"144","members_count":4},{"name":"145","members_count":4},{"name":"146","members_count":3},{"name":"147","members_count":5},{"name":"148","members_count":2},{"name":"149","members_count":1},{"name":"150","members_count":2},{"name":"151","members_count":3},{"name":"152","members_count":0},{"name":"153","members_count":3},{"name":"154","members_count":1},{"name":"155","members_count":2},{"name":"156","members_count":2},{"name":"157","members_count":1},{"name":"158","members_count":5},{"name":"159","members_count":4},{"name":"160","members_count":4},{"name":"161","members_count":5},{"name":"162","members_count":4},{"name":"163","members_count":2},{"name":"164","members_count":4},{"name":"165","members_count":2},{"name":"166","members_count":2},{"name":"167","members_count":1},{"name":"168","members_count":1},{"name":"169","members_count":10},{"name":"170","members_count":4},{"name":"171","members_count":2},{"name":"172","members_count":2},{"name":"173","members_count":1},{"name":"174","members_count":5},{"name":"175","members_count":1},{"name":"176","members_count":1},{"name":"177","members_count":5},{"name":"178","members_count":3},{"name":"179","members_count":1},{"name":"180","members_count":5},{"name":"181","members_count":8},{"name":"182","members_count":4},{"name":"183","members_count":2},{"name":"184","members_count":1},{"name":"185","members_count":3},{"name":"186","members_count":1},{"name":"187","members_count":3},{"name":"188","members_count":1},{"name":"189","members_count":1},{"name":"190","members_count":6},{"name":"191","members_count":4},{"name":"192","members_count":5},{"name":"193","members_count":1},{"name":"194","members_count":4},{"name":"195","members_count":2},{"name":"196","members_count":2},{"name":"197","members_count":2},{"name":"198","members_count":0},{"name":"199","members_count":3},{"name":"200","members_count":3},{"name":"201","members_count":1},{"name":"202","members_count":1},{"name":"203","members_count":1},{"name":"204","members_count":5},{"name":"205","members_count":1},{"name":"206","members_count":1},{"name":"207","members_count":1},{"name":"208","members_count":1},{"name":"209","members_count":1},{"name":"210","members_count":5},{"name":"211","members_count":2},{"name":"212","members_count":1},{"name":"213","members_count":5},{"name":"214","members_count":1},{"name":"215","members_count":3},{"name":"216","members_count":1},{"name":"217","members_count":1},{"name":"218","members_count":4},{"name":"219","members_count":2},{"name":"220","members_count":1},{"name":"221","members_count":3},{"name":"222","members_count":1},{"name":"223","members_count":3},{"name":"224","members_count":1},{"name":"225","members_count":2},{"name":"226","members_count":1},{"name":"227","members_count":1},{"name":"228","members_count":11},{"name":"229","members_count":9},{"name":"230","members_count":9},{"name":"231","members_count":9},{"name":"232","members_count":10},{"name":"233","members_count":10},{"name":"234","members_count":10},{"name":"235","members_count":9},{"name":"236","members_count":10},{"name":"237","members_count":10},{"name":"238","members_count":10},{"name":"239","members_count":10},{"name":"240","members_count":9},{"name":"241","members_count":9},{"name":"242","members_count":9},{"name":"243","members_count":10},{"name":"244","members_count":10},{"name":"245","members_count":9},{"name":"246","members_count":2},{"name":"247","members_count":1},{"name":"248","members_count":2},{"name":"249","members_count":2},{"name":"250","members_count":1},{"name":"251","members_count":2},{"name":"252","members_count":1},{"name":"253","members_count":5},{"name":"254","members_count":1},{"name":"255","members_count":1},{"name":"256","members_count":1},{"name":"257","members_count":1},{"name":"258","members_count":1},{"name":"259","members_count":1},{"name":"260","members_count":2},{"name":"261","members_count":1},{"name":"262","members_count":1},{"name":"263","members_count":2},{"name":"264","members_count":1},{"name":"265","members_count":1},{"name":"266","members_count":1},{"name":"267","members_count":1},{"name":"268","members_count":2},{"name":"269","members_count":2},{"name":"270","members_count":1},{"name":"271","members_count":1},{"name":"272","members_count":0},{"name":"273","members_count":2},{"name":"274","members_count":1},{"name":"275","members_count":2},{"name":"276","members_count":2},{"name":"277","members_count":1},{"name":"278","members_count":3},{"name":"279","members_count":1},{"name":"280","members_count":1},{"name":"281","members_count":1},{"name":"282","members_count":1},{"name":"283","members_count":1},{"name":"284","members_count":1},{"name":"285","members_count":1},{"name":"286","members_count":1},{"name":"287","members_count":1},{"name":"288","members_count":1},{"name":"289","members_count":1},{"name":"290","members_count":1},{"name":"291","members_count":1},{"name":"292","members_count":1},{"name":"293","members_count":1},{"name":"294","members_count":1},{"name":"295","members_count":1},{"name":"296","members_count":1},{"name":"297","members_count":2},{"name":"298","members_count":2},{"name":"299","members_count":1},{"name":"300","members_count":1},{"name":"301","members_count":1},{"name":"302","members_count":1},{"name":"303","members_count":1},{"name":"304","members_count":1},{"name":"305","members_count":1},{"name":"306","members_count":1},{"name":"307","members_count":1},{"name":"308","members_count":1},{"name":"309","members_count":1},{"name":"310","members_count":1},{"name":"311","members_count":1},{"name":"312","members_count":1},{"name":"313","members_count":0},{"name":"314","members_count":1}]
This is chart's drawing code.
var margin = {top: 20, right: 20, bottom: 30, left: 40},
width = (960 - margin.left - margin.right) * data.length/50,
height = 500 - margin.top - margin.bottom;
var x = d3.scale.ordinal()
.domain([0,1])
.rangeRoundBands([0, width], 0.1);
var y = d3.scale.linear()
.range([height, 0]);
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom")
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.ticks(10, "%");
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 + ")");
x.domain(data.map(function(d) { return d.name; }));
y.domain([0, d3.max(data, function(d) { return d.members_count; })]);
svg.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
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("Frequency");
svg.selectAll(".bar")
.data(data)
.enter().append("rect")
.attr("class", "bar")
.attr("fill","green")
.attr("x", function(d) { return x(d.name); })
.attr("width", x.rangeBand())
.attr("y", function(d) { return y(d.members_count); })
.attr("height", function(d) { return height - y(d.members_count); });
This issue I am getting is that I have some white space which looks ugly. This space come before the 1st bar and also after the last bar of the chart. I have tried tweaking the x value of the bar, But I think that is not a good way to do.
This space does not come when the data set is small. But when dataset is large then this space comes up. How can I remove this space from the start and from end.

The problem is with this line in scale:
.rangeRoundBands([0, width], 0.1);
When there is not specified the third parameter outerPadding it adds before and after the chart extra space produced by the padding parameter for each bar. You have set the padding to 0.1. To solve this problem set the outerPadding parameter:
var x = d3.scale.ordinal()
.domain([0,1])
.rangeRoundBands([0, width], 0.1, 0);
Here is updated your code: http://jsfiddle.net/ojntup1a/

How do you move number labels further away from the x-axis in d3.js?

Newbie question: How can one move the x-axis tick labels further from the x-axis? The snippet of code below produces this:
Whereas what I want is more like this:
From the question here:
d3.js: Align text labels between ticks on the axis
it seems that I need to select the text that contains these labels using select and then apply something like translate(0,-10) to them, but I can't figure out where this text "lives"/the syntax for performing such a selection. Sorry if this is simple; I am very new to D3 (and javascript). Can anyone help? Thanks in advance! Code follows.
<script>
var superscript = "⁰¹²³⁴⁵⁶⁷⁸⁹",
formatPower = function(d) { return (d + "").split("").map(function(c) { return superscript[c]; }).join("");\
};
var margin = {top: 20, right: 20, bottom: 100, left: 100},
width = 400,
height = 400;
var x = d3.scale.log()
.domain([1e1, 1e4])
.range([0, width])
.nice();
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom")
.tickValues([1e1, 1e2, 1e3, 1e4])
.ticks(0, function(d) { return 10 + formatPower(Math.round(Math.log(d) / Math.LN10)); });
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", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.append("text")
.attr("class", "label")
.attr("x", (width+margin.left)/2)
.attr("y", 60)
.style("text-anchor", "end")
.text("x-axis label");
</script>

There's a simpler way to do this using tickPadding. Where you define xAxis, just add .tickPadding(15) (change 15 to the number of pixels you want).
Example here: http://jsfiddle.net/henbox/5q4k2r0p/1/

d3 Focus + Context via Brushing not displaying anything

i am trying to visualize some data using Focus + Context via brushing using D3. I am having some problems with the data. I have just changed the data fetch lines of code since i am fetching 2 values using d3.json. Here is my code -
<script type="text/javascript">
var margin = {top: 10, right: 10, bottom: 100, left: 40},
margin2 = {top: 430, right: 10, bottom: 20, left: 40},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom,
height2 = 500 - margin2.top - margin2.bottom;
var parseDate = d3.time.format("%a %e %H %M").parse;
var x = d3.time.scale().range([0, width]),
x2 = d3.time.scale().range([0, width]),
y = d3.scale.linear().range([height, 0]),
y2 = d3.scale.linear().range([height2, 0]);
var xAxis = d3.svg.axis().scale(x).orient("bottom"),
xAxis2 = d3.svg.axis().scale(x2).orient("bottom"),
yAxis = d3.svg.axis().scale(y).orient("left");
var brush = d3.svg.brush()
.x(x2)
.on("brush", brushed);
var area = d3.svg.area()
.interpolate("monotone")
.x(function(d) { return x(d.receiveddate); })
.y0(height)
.y1(function(d) { return y(d.gtse); });
var area2 = d3.svg.area()
.interpolate("monotone")
.x(function(d) { return x2(d.receiveddate); })
.y0(height2)
.y1(function(d) { return y2(d.gtse); });
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
svg.append("defs").append("clipPath")
.attr("id", "clip")
.append("rect")
.attr("width", width)
.attr("height", height);
var focus = svg.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var context = svg.append("g")
.attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");
d3.json("rest.php/lastweek"+"/"+"dibya", function(error, data) {
var allData = data.records;
allData.forEach(function(d) {
var formattedDate = new Date(+d.receiveddate).toString();
d.receiveddate = parseDate(d3.time.format("%a %e %H %M")(new Date(formattedDate)));
d.gtse = +d.gtse;
});
x.domain(d3.extent(allData.map(function(d) { return d.receiveddate; })));
y.domain([0, d3.max(allData.map(function(d) { return d.gtse; }))]);
x2.domain(x.domain());
y2.domain(y.domain());
focus.append("path")
.datum(data)
.attr("clip-path", "url(#clip)")
.attr("d", area);
focus.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
focus.append("g")
.attr("class", "y axis")
.call(yAxis);
context.append("path")
.datum(data)
.attr("d", area2);
context.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height2 + ")")
.call(xAxis2);
context.append("g")
.attr("class", "x brush")
.call(brush)
.selectAll("rect")
.attr("y", -6)
.attr("height", height2 + 7);
});
function brushed() {
x.domain(brush.empty() ? x2.domain() : brush.extent());
focus.select("path").attr("d", area);
focus.select(".x.axis").call(xAxis);
}
Here the received date is fetched as date in Millis and converted accordingly. The received date is in the frequency of 10 mins. The browser loads the x and y axes according to the values passed but no graph is plotted. Neither do i get any error in console. What am i missing?