D3.js -- How do I update dataset via Javascript? - javascript

I have a dataset with 11 different variables (csv file with 12 columns). I want to be able to select a certain column for my scatterplot, but I'm having some difficulties. Please bear with me, as JavaScript is not my strong suit (obviously). Here's what I attempted:
<div class="variables" id="fixedacidity" onclick="drawPlot('fixedacidity');">
<h1>fixed acidity</h1>
</div>
<div class="variables" id="volatileacidity" onclick="drawPlot('volatileacidity');">
<h1>volatile acidity</h1>
</div>
<div class="variables" id="citricacid" onclick="drawPlot('citricacid');">
<h1>citric acid</h1>
</div>
<div class="variables" id="residualsugar" onclick="drawPlot('residualsugar');">
<h1>residual sugar</h1>
</div>
etc ...
I made a simple menu that calls on the drawPlot function, but I'm having trouble trying to get the variable to pass on correctly.
Relevant d3/javascript:
function drawPlot(selectedVar){
$(".visarea").html("");
var wineVar = selectedVar;
var margin = {top: 20, right: 20, bottom: 30, left: 40},
width = 860 - margin.left - margin.right,
height = 350 - margin.top - margin.bottom;
var x = d3.scale.linear()
.range([0, width]);
var y = d3.scale.linear()
.range([height, 0])
.domain([0,10]);
var color = d3.scale.category10();
var xAxis = d3.svg.axis()
.scale(x)
.orient("bottom");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left").ticks(10);
var chart1 = d3.select(".visarea").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 + ")");
d3.csv("red.csv", function(error, data) {
if (error) throw error;
data.forEach(function(d) {
d.wineVar = +d.wineVar;
d.quality = +d.quality;
});
x.domain(d3.extent(data, function(d) { return d.wineVar; })).nice();
y.domain([0,10]).nice();
chart1.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis)
.append("text")
.attr("class", "label")
.attr("x", width)
.attr("y", -6)
.style("text-anchor", "end")
.text(wineVar);
chart1.append("g")
.attr("class", "y axis")
.call(yAxis)
.append("text")
.attr("class", "label")
.attr("transform", "rotate(-90)")
.attr("y", 6)
.attr("dy", ".71em")
.style("text-anchor", "end")
.text("Rated Quality")
chart1.selectAll(".red.dot")
.data(data)
.enter().append("circle")
.attr("class", "red dot")
.attr("r", 3)
.attr("cx", function(d) { return x(d.wineVar); })
.attr("cy", function(d) { return y(d.quality); })
.style("fill", "red");
});
}
Although the variable gets passed on to the function, d.wineVar, as expected, does not return the desired value, and thus the chart does not draw the correct values. Can anyone recommend a workaround for this? It seems so simple, yet I've spent hours failing trying to figure this out.
Sample of red.csv:
fixedacidity,volatileacidity,citricacid,residualsugar,chlorides,freesulfurdioxide,totalsulfurdioxide,density,pH,sulphates,alcohol,quality
7.4,0.7,0,1.9,0.076,11,34,0.9978,3.51,0.56,9.4,5
7.8,0.88,0,2.6,0.098,25,67,0.9968,3.2,0.68,9.8,5
7.8,0.76,0.04,2.3,0.092,15,54,0.997,3.26,0.65,9.8,5
Image of what I'm trying to accomplish. The first dataset, fixedacidity, gets drawn up fine. I'm having difficulties trying to get the menu to correctly show its respective dataset. "Rated Quality" will always be the data for the Y-axis.

You has wrong variable reference, here:
data.forEach(function(d) {
d.wineVar = +d.wineVar; // <---------Here
d.quality = +d.quality;
});
change by:
data.forEach(function(d) {
d.wineVar = +d[wineVar]; // <----------Here
d.quality = +d.quality;
});

There is the obvious issue pointed out by klaujesi about data extraction. But there are more issues with your code.
I would say you need to adapt your approach to the way d3.js works. Currently you will add a new svg on each call to the function, caused by this line in your code: d3.select(".visarea").append("svg")
I usually have some init code wrapped in one function, which creates the svg and sets ups everything static. Then there is an update function which will handle input changes to show different data, use different scales etc.
The nice thing about d3.js is that you can control very easily what's to happen with newly introduced data via .enter() and removed data via .exit().

Related

d3 array input line graph example

I'm very new to d3 and in order to learn I'm trying to manipulate the d3.js line example, the code is below. I'm trying to modify this to use model data that I already have on hand. This data is passed down as a json object. The problem is that I don't know how to manipulate the data to fit what d3 expects. Most of the d3 examples use key-value arrays. I want to use a key array + a value array. For example my data is structured per the example below:
// my data. A name property, with array values and a value property with array values.
// data is the json object returned from the server
var tl = new Object;
tl.date = data[0].fields.date;
tl.close = data[0].fields.close;
console.log(tl);
Here is the structure visually (yes it time format for now):
Now this is different from the data.tsv call which results in key-value pairs in the code below.
The goal is to use my data as is, without having to iterate over my array to preprocess it.
Questions:
1) Are there any built in's to d3 to deal with this situation? For example, if key-values are absolutely necessary in python we could use the zip function to quickly generate a key-value list.
2) Can I use my data as is, or does it have to be turned into key-value pairs?
Below is the line example code.
// javascript/d3 (LINE EXAMPLE)
var margin = {top: 20, right: 20, bottom: 30, left: 50},
width = 640 - margin.left - margin.right,
height = 480 - margin.top - margin.bottom;
var parseDate = d3.time.format("%d-%b-%y").parse;
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");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var line = d3.svg.line()
.x(function(d) { return x(d.date); })
.y(function(d) { return y(d.close); });
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 + ")");
d3.tsv("/data.tsv", function(error, data) {
data.forEach(function(d) {
d.date = parseDate(d.date);
d.close = +d.close;
});
x.domain(d3.extent(data, function(d) { return d.date; }));
y.domain(d3.extent(data, function(d) { return d.close; }));
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("Price ($)");
svg.append("path")
.datum(data)
.attr("class", "line")
.attr("d", line);
});
Check out d3's array functions, zip is among them.
Here's a commented version of the original gist working with your data: http://bl.ocks.org/patrickberkeley/9162034
The core of it is this:
// 1) Zip the close value with their corresponding date/time
// Results in an array of arrays:
//
// [[582.13, "02:30:00"], [583.98, "02:45:00"], ...]
//
data = d3.zip(data.close, data.date).map(function(d) {
// 2) Format each close and date/time value so d3 understands what each represents.
close = +d[0];
// If your data source can't be changed at all, I'd rename `date` to `time` here.
date = parseTime(d[1]);
// 3) Return an object for each close and date/time pair.
return {close: close, date: date};
});
You can pass one of your arrays to .data() and use the index to get the respective element from the other:
var line = d3.svg.line()
.x(function(d) { return x(d); })
.y(function(d, i) { return y(tl.close[i]); });
svg.selectAll("path")
.data([tl.date])
.enter().append("path")
.attr("d", line);
You just have to remember to set the domains of the scales you're using with the correct arrays.

D3.js not displaying chart

I am using D3 for the first time and I have followed the instructions on their site to get to this point. I cannot seem to get the chart to display although there are no exceptions in the JS console in Chrome.
Here's the JS in the header of my page:
<script>
var margin = {
top: 0,
right: 0,
bottom: 10,
left: 0
},
width = 838 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
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");
var yAxis = d3.svg.axis()
.scale(y)
.orient("left");
var chart = d3.select(".day_chart")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
d3.json("http://solarmonitoringaustralia.com.au/myphp/inverterdata.php?var=TEST1&id=C120031", function (error, data) {
data.forEach(function (d) {
d.hour = +d.hour; // coerce to number
d.max_energy = +d.max_energy;
alert(d.hour + " -- " + d.max_energy);
});
x.domain(data.map(function (d) {
return d.hour;
}));
y.domain([0, d3.max(data, function (d) {
return d.max_energy;
})]);
chart.append("g")
.attr("class", "x axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
chart.append("g")
.attr("class", "y axis")
.call(yAxis);
chart.selectAll(".bar")
.data(data)
.enter().append("rect")
.attr("class", "bar")
.attr("x", function (d) {
return x(d.hour);
})
.attr("y", function (d) {
return y(d.max_energy);
})
.attr("height", function (d) {
return height - y(d.max_energy);
})
.attr("width", x.rangeBand());
});
</script>
The code calls in a JSON request to a server side script. Here's the data it returns to the browser when executing the query:
[{"hour":"1","max_energy":"15.969"},{"hour":"2","max_energy":"19.065"},{"hour":"3","max_energy":"21.191"},{"hour":"4","max_energy":"23.151"},{"hour":"5","max_energy":"24.403"},{"hour":"6","max_energy":"25.082"},{"hour":"7","max_energy":"25.494"},{"hour":"8","max_energy":"25.499"},{"hour":"9","max_energy":"4.685"},{"hour":"10","max_energy":"7.309"},{"hour":"11","max_energy":"10.051"},{"hour":"12","max_energy":"13.119"}]
My HTML contains this tag where I want the chart to appear:
<sgv class="day_chart"></svg>
I can see the data passing into the JS above via the "alert" function in the data.forEach(function (d), so the data comes back.
The page loads but it loads with a blank area where the chart would go, and no JS errors in the console. Thanks for any advice!
Well, this one's going to be a face-palm moment.
The only thing wrong was a typo.
<sgv class="day_chart"></svg>
Should of course be
<svg class="day_chart"></svg>
I've got a working version here
http://jsfiddle.net/cZxey/11/
(I also set the library to load D3, and inserted hard-coded data. For working with the real data, just comment that out. Oh, and increase your bottom padding so your tick mark labels don't get cut off.)
--ABR

x-axis zooming with d3 line charts

I'm just getting into using d3, and relatively novice in js still. I'm trying to set up a page of log file visualizations for monitoring some servers. Right now I'm focusing on getting a line chart of CPU utilization, where I can focus on specific time periods (So an x-zoom only). I am able to do a static charts easily, but when it comes to the zooming the examples are going over my head and I can't seem to make them work.
This is the static example I followed to get things up and running, and this is the zoom example I've been trying to follow.
My input csv is from a rolling set of log files (which will not be labled on the first row), each row looks like this:
datetime,server,cpu,memory,disk,network_in,network_out
So far what I've been able to get on the zoom looks like this:
var parseDate = d3.time.format("%Y-%m-%d %H:%M:%S").parse;
// define dimensions of graph
var margin = {top: 20, right: 80, bottom: 30, left: 50},
width = 960 - margin.left - margin.right,
height = 200 - margin.top - margin.bottom;
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")
.tickSize(-height, 0)
.tickPadding(6);
var yAxis = d3.svg.axis()
.scale(y)
.orient("left")
.tickSize(-width)
.tickPadding(6);
// Define how we will access the information needed from each row
var line = d3.svg.line()
.interpolate("step-after")
.x(function(d) { return x(d[0]); })
.y(function(d) { return y(d[2]); });
// Insert an svg element into the document for each chart
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 + ")");
// Declare zoom handler
var zoom = d3.behavior.zoom().on("zoom", draw);
// Open the log and extract the information
d3.text("log.csv", function(text) {
var data = d3.csv.parseRows(text).map(function(row) {
return row.map(function(value, index) {
if (index == 0) {
return parseDate(value);
}
else if (index > 1) {
return +value;
}
else {
return value;
}
});
});
// Set the global minimum and maximums
x.domain(d3.extent(data, function(d) { return d[0]; }));
y.domain(d3.extent(data, function(d) { return d[2]; }));
zoom.x(x);
// Finally, we have the data parsed, and the parameters of the charts set, so now we
// fill in the charts with the lines and the labels
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")
.attr("text-anchor", "end")
.text("Percent (%)");
svg.append("path")
.datum(data)
.attr("class", "line")
.attr("d", line);
svg.append("text")
.attr("x", margin.left)
.attr("y", 0 - (margin.top / 2))
.attr("text-anchor", "middle")
.text('all');
svg.append("rect")
.attr("class", "pane")
.attr("width", width)
.attr("height", height)
.call(zoom);
svg.select("path.line").data([data]);
draw();
});
function draw() {
svg.select("g.x.axis").call(xAxis);
svg.select("g.y.axis").call(yAxis);
svg.select("path.line").attr("d", line);
}
What this gives me is a very sluggish chart that can be zoomed and panned, but it does not clip off the line at the ends of the chart. I've tried adding in the clipping elements described in the example, but that ends up fully erasing my line every time.
Thanks for any help or direction

Dynamically update chart data in D3

I'm working on a real-time visualization of incoming data. I use D3 for the visualization and started based on this example: http://bl.ocks.org/mbostock/3883195
This is the version I'm currently working on:
var margin = {top: 20, right: 20, bottom: 30, left: 50},
width = 500 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom;
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");
var yAxis = d3.svg.axis().scale(y).orient("left");
var area = d3.svg.area()
.x(function(d) { return x(d.x); })
.y0(height)
.y1(function(d) { return y(d.y); });
var svg = d3.select("div#chart").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 + ")");
var data = [[1,1],[2,3],[3,2],[4,4]];
var dataCallback = function(d) {
d.x = +d[0];
d.y = +d[1];
};
data.forEach(dataCallback);
x.domain(d3.extent(data, function(d) { return d.x; }));
y.domain([0, d3.max(data, function(d) { return d.y; })]);
svg.append("path")
.datum(data)
.attr("class", "area")
.attr("d", area);
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("Number of Messages");
This produces the following graph:
Now, as it should update itself regularly, I wanted to dynamically update the data in the graph using the following code:
var n = svg.selectAll("path").data([5,20])
n.enter();
n.exit().remove();
However, that does not work. I'm new to D3 and still learning the basics. Ideally, the graph visualization shifts to the left and the new data is shown in the graph. But so far I can't even add new data to it. Could someone help me with that? I also searched for examples similar to this, but did not found anything which really helped me so far.
d3 is pretty good at keeping track of what data's been added and what's being removed - it does this with joins. Take a look at http://bl.ocks.org/mbostock/3808218
IF we use the data binding (instead of "datum")
svg.append("path")
.data([data])
.attr("class", "area")
.attr("d", area);
and then on update do something like:
// update the list of coordinates
data.splice(0,1);
data.push([5,20]);
// re-decorate the last, newly added item
dataCallback(data[data.length - 1]);
// You will also need to update your axes
x.domain(d3.extent(data, function(d) { return d.x; }));
y.domain([0, d3.max(data, function(d) { return d.y; })]);
// update the data association with the path and recompute the area
svg.selectAll("path").data([data])
.attr("d", area);
And you should get your area to update.
You can try it out here
With the way your data is organized using the joined data (instead of datum) may not make much difference. Note that here the (single) data element you are associating with the path is the full list of coordinates so to update the area you need to pass in a new full list of coordinates.
If you really want to minimized the amount you need to redraw you could break up the area and draw each line segment. Then essentially you fall back to the bar chart example but with not-flat bars and no spacing.

How do I update this data without redrawing datapoints that are already there?

New to D3. I am trying to modify the simple bar chart example shown here. I'm trying to update the data but am missing something fundamental. I'm trying to follow along here, where Mike talks about object constancy. Specifically, I am trying to achieve the following in my code:
Key functions can be useful for improving performance independent of transitions. For example, if you filter a large table, you can use a key function to reduce the number of DOM modifications: reorder DOM elements in the update selection rather than regenerating them. We used this technique at Square to improve the performance of merchant analytics, and it’s one of the reasons that D3 is faster than most template frameworks.
(In my case, my key function is simply ".data(data)" (which is ok, according to this post)
My code below works, but I suspect isn't the most performance friendly. For instance, frequency "70" is in both sets of data, but by "removing" the data, I am effectively redrawing it. (If I don't "remove" the data first, then another chart is drawn, rather than the old chart just getting updated data). How do I modify the code below to adhere to the key function and so that data that exists in both datasets doesn't get redrawn?
My code for the bar chart:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
font: 10px sans-serif;
}
.axis path,
.axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
.bar {
fill: steelblue;
}
.x.axis path {
display: none;
}
</style>
<body>
<button id="change" name="change">Update</button>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js" type="text/javascript"></script>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
$(document).ready(function () {
var old_data = [{"letter": "A","frequency": "50"},
{"letter": "B","frequency": "60"},
{"letter": "C","frequency": "70"}, // this also appears in new_data
{"letter": "D","frequency": "80"},
];
draw_chart(old_data);
$("#change").click(function(){
var new_data = [{"letter": "A","frequency": "10"},
{"letter": "B","frequency": "20"},
{"letter": "C","frequency": "70"}, // this appears in old_data
{"letter": "D","frequency": "30"},
];
var bar = d3.select('body').selectAll('svg').remove();// delete this line and you'll get multiple charts rather than just updating the data in the original chart
draw_chart(new_data);
});
});
</script>
<script>
function draw_chart(data){
var margin = {top: 20, right: 20, bottom: 30, left: 40},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
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");
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 + ")");
data.forEach(function(d) {
d.frequency = +d.frequency;
});
x.domain(data.map(function(d) { return d.letter; }));
y.domain([0, d3.max(data, function(d) { return d.frequency; })]);
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("x", function(d) { return x(d.letter); })
.attr("width", x.rangeBand())
.attr("y", height)
.attr("height","0")
.transition()
.delay(function(d, i) { return i*300 })
.duration(1000)
.attr("y", function(d) { return y(d.frequency); })
.attr("height", function(d) { return height - y(d.frequency); });
}
</script>
First, the reason why you have the line,
var bar d3.select('body')...remove() // delete this line and you'll get double...
Is beacuse in your draw_chart your always appending to the page when it's called. You need to change this line,
var svg = d3.select("body").append("svg")
to something that doesn't continually append a new svg
If I have more time i'll take a look at the main question.

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