Svcc 2013-d3

D3 for Data Visualization on
Desktops, Smart Phones, and
Google Glass
SVCC (10/05/2013)
Foothill College Los Altos
Oswald Campesato
oswald@swiftbot.com
ocampesato@yahoo.com

Pace and Sequence of Topics
This session moves quickly
Focus is primarily on demos
topics are discussed based on their
relevance in demos (i.e., not
necessarily sequential)
Some code will be made available
later

Our Hat for Work-Related Topics:

Our Hat for Fun-Related Topics:

How/Where do the Demos Work?
All demos work on desktop/laptops:
launched as HTML5 Web pages
Demos created as Android apks work on:
mobile phones, tablets, and Google Glass
• Android apks can be created via:
Eclipse/PhoneGap/Android Studio/other

What is D3?
open source project (2010)
Mike Bostock (principal/creator)
based on JavaScript
a layer of "abstraction" over SVG
also support for HTML5 Canvas
github.com/mbostock/d3
https://github.com/mbostock/d3/wiki/
Gallery

Why/When use D3?
data visualization
extremely versatile
leverage JavaScript skills
leverage SVG
Create HTML5 Web pages with D3 and:
HTML5 Canvas, CSS3, SVG, jQuery, …

What Can D3 Do?
All the stuff you can do in SVG
graphics/animation
filters/gradients
mouse/keyboard events
custom charts/graphs
Support for Ajax, JSON, XML, CSV files

How Does D3 Work?
Creates SVG elements via JavaScript
Often involves “method chaining”:
svg.selectAll()
.attr(a, “b”)
.attr(c,”d”)…
select-data-enter-append:
"TMCIID3” ("The Most Common Idiom in D3”)

Simple D3 Example
<head>
<script src="d3.min.js"></script>
<script>
d3.select("body")
.append("p")
.text("Hello1 D3");
</script>
<body>
<p>Hello1 D3</p>
</body>

Adding SVG: General Approach
#1: create/append an <svg> element to <body>
#2: often define JavaScript array(s) of values
#3: iterate through arrays create SVG elements:
use constants/variables/anonymous functions
Optional:
#4: add event listener(s)
#5: add animation-related code

Creating a Circle in D3 (part 1)
1) First create an <svg> element:
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height",height);

Creating a Circle in D3 (part 2)
2) Include the following D3 code:
svg.append("circle")
.attr("cx", 10)
.attr("cy", 10)
.attr("r", 100)
.attr("fill", "red")
D3 code generates this SVG element:
<body>
<circle cx="10" cy="10” r="100" fill="red" />
</body>

A Scatter Chart (part 1)
Step #1 define a JS array with data values:
var dataXValues=[10, 50, 20, 80,150,180,220];
Step #2 Create an SVG element:
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);

A Scatter Chart (part 2)
Step 3 create and append circles:
var circles = svg.selectAll("circles")
.data(dataXValues)
.enter()
.append("circle")
.attr("cx", function(d, i) {
return (d*5*Math.random());
})
.attr("cy", function(d, i) {
return (d*5*Math.random());
})
.attr("r", radius).style("fill", "red");

Using Arrays for all Circle Attributes
var generalizedCircles = svg.selectAll("circles")
.data(dataXValues).enter().append("circle")
.attr("cx", function(d, i) { return d; })
.attr("cy", function(d, i) { return dataYValues[i]; })
.attr(”r", function(d, i) { return dataRValues[i];
})
.style (”fill", function(d, i) { return dataFValues[i];})

Using Arrays for Rectangle Attributes
var generalizedRectangles = svg.selectAll(”rect")
.data(dataXValues).enter().append(”rect")
.attr(“x", function(d, i) { return dataXValues[i]; })
.attr(“y", function(d, i) { return dataYValues[i]; })
.attr(”width", function(d, i) { return dataWValues[i]; })
.attr(”height", function(d, i) { return dataHValues[i]; })
.style (”fill", function(d, i) { return dataFValues[i]; })

Mouse Handler for ScatterChart
circles.on("mouseover",function() {
d3.select(this) // the “mouseover” circle
.transition()
.duration(duration)
.attr("transform", function() {
var sx = 1+Math.random();
var sy = 1-Math.random();
return "scale("+sx+","+sy+")";
})
})

Examples of Transforms in D3
yourPreviouslyCreatedElement
.attr("transform", "translate(50,100)")
.attr("transform", "rotate(40)")
.attr("transform", "scale(0.5,1.3)")
.attr("transform", "skewX(20)")

Easing Functions (Animation Effects)
Create an SVG element and append this code:
.on("mouseover",function(){
.duration(1000)
.delay(200)
.ease("out-elastic",1,1)
})
At least 10 easing functions available

Bar Charts in D3
Scale horizontal/vertical values
Various label types (numeric/date) for axes
Unicode support
Add mouse events to „bar‟ elements

D3 and SVG Filters
Define an SVG <filter> element (in <defs>):
<defs>
…
<filter id="blurFilter1”>
<feGaussianBlur "stdDeviation"=4>
</feGaussianBlur>
</filter>
…
</defs>

How to Define Filters in D3
var defs = svg.append("defs")
defs.append("svg:filter")
.attr("id", "blurFilter1")
.append("svg:feGaussianBlur")
.attr("stdDeviation", 4);
The preceding code is equivalent to this code:
<filter id="blurFilter1”>
<feGaussianBlur "stdDeviation"=4 />
</filter>

D3 and SVG Linear Gradients
Insert this code in an SVG <defs> element:
<linearGradient id="GradientL"
gradientUnits="userSpaceOnUse"
cx="100" cy="50" r="160"
fx="100" fy="50">
<stop offset="0%" stop-color="red"/>
<stop offset="33%" stop-color="blue"/>
<stop offset="67%" stop-color="red"/>
<stop offset="100%" stop-color="blue"/>
</linearGradient>

D3 Linear Gradients
var gradientL = defsElement
.append("svg:linearGradient")
.attr("id", "GradientL")
.attr("x1", "0%")
.attr("y1", "0%")
.attr("x2", "100%")
.attr("y2", "100%")
.attr("gradientUnits",
"userSpaceOnUs”)
Append-stop-colors…

D3 and SVG <pattern> Elements
Insert in the SVG <defs> element:
<pattern id="checkerPattern"
width="40" height="40"
patternUnits="userSpaceOnUse”>
<rect fill="url(#gradientDefinition1)"
x="0" y="0" width="40" height="40"/>
</pattern>
D3 code for an SVG pattern: exercise

SVG and Maps
 Election maps for presidential race:
 ABC: Raphaël/SVG
 Washington Post: Leaflet/SVG+HTML
 Politico: Raphaël/SVG
 NYT: Custom? Canvas/HTML
 RealClearPolitics: Raphaël/SVG
 FoxNews: Raphaël/SVG
 MSNBC: Raphaël/SVG
 Google: PolyGonzo/Canvas
 HuffingtonPost: Raphaël/SVG
 BBC: Raphaël/SVG

D3 APIs/Extensions/Plugins
Choropleth
Maps (stereographic projection/others)
Force diagrams
Extensions/plugins:
RickShaw
CS
Extensions:
Cubed

D3 and CSV Files
Read data from a CSV file (1,000 rows)
Each row represents a line segment
Add a mouseover event listener
Append line coordinates to a second
array when users „mouse over‟ that
segment
Works fine for up to 4,000 rows

What about Large Datasets?
Superconductor.js:
DSL/JS/Web Workers
Uses a <canvas> element
“browser in a browser”
Smoothly handles 100K data points
• Druid (Metamarkets)
• Weave/Yarn (Apache): layer over Hadoop
• Kafka, Storm, and D3 (more recent)

D3 and Other Technologies
D3 and BackboneJS in one Web page
D3 and AngularJS in one Web Page
Use D3 with HTML5 Web Sockets
D3 with NodeJS (and Meteor)

D3 and CSS3
CSS3 2D transforms:
rotate, scale, skew, translate, matrix, and
perspective
• CSS3 3D transforms:
Similar to 2D versions (but no „skew‟)
Also three axis-specific methods:
rotateX, rotateY, rotateZ
• More details in next session

Spherical Coordinates
(1) x = w*cos(a); y = w*sin(a);
(2) z = r*sin(b);
(3) w = r*cos(b);
Substitute (3) into (1) to get:
(4) x = r*cos(b)*cos(a);
(5) y = r*sin(b)*sin(a);
(6) z = r*cos(b);

D3 and Android
1) Create an Android application Test
2) modify $TOP/res/layout/activity_main.xml:
insert a WebView component
3) create $TOP/assets/www
4) copy TestD3.html into $TOP/assets/www
5) modify src/com/Test.java:
reference TestD3.html in onCreate()

Contents of main.xml
<?xml version="1.0" encoding="utf-8"?>
<WebView
 xmlns:android="http://….”
 android:id="@+id/webview"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
/>

Contents of onCreate() Method
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Your new code goes here:
mWebView = (WebView) findViewById(R.id.webview);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.getSettings().setDomStorageEnabled(true);
mWebView.loadUrl(
"file:///android_asset/www/Test3D.html");

What is PhoneGap?
A Plugin to create Hybrid Mobile apps
Available on 6 platforms
A JavaScript “bridge”
Access to hardware (camera/etc)
No compilation required
No Java/Objective-C code
Handles the manual steps for you
Creates an index.html Web page

Why use PhoneGap?
No compilation required
No Java/Objective-C code
Handles the manual steps for you
Provides access to hardware (camera/etc)

D3 and Google Glass
Create an Android apk in Eclipse
Deploy to Glass:
adb install D3Demo.apk
• Find the package and main Android Activity:
Let‟s call them “a.b.c” and “D3Main”
* Launch from the command line:
adb shell am start -a android.intent.action.MAIN
-n a.b.c/.D3Demo

D3 Resources
online forums (Google group)
meetups in BA
Stackoverflow
code.google.come/p/d3-graphics

25 JavaScript Visualization Libraries
http://www.ma-no.org/en/content/index_visualize-your-
data-25-javascript-visualization-libraries_1796.php

Open Source Projects
• Graphics Projects on http://code.google.com/p:
+ css3-graphics and html5-canvas-graphics
+ css3-jquery-graphics and d3-graphics
+ svg-graphics and svg-filters-graphics
+ easel-graphics, fabric-graphics, paper-graphics
+ ThreeJS, jQuery, Raphael, Google Go, Android
+ Dart, Dojo, JSF, Two.js, JavaFX 2.0
+ Lua, PHP, Perl, Python, Ruby, SWT graphics

Some Training Topics
• D3/SVG
• HTML5 (CSS3/Canvas/etc)
jQuery/jQuery Mobile
Android (iOS later)
BackboneJS/PhoneGap

Recent/Upcoming Books
1) HTML5 Canvas and CSS3 Graphics (2012)
2) jQuery, CSS3, and HTML5 for Mobile (2013)
3) HTML5 Pocket Primer (2013)
4) jQuery Pocket Primer (2013)
5) HTML5 Mobile Pocket Primer (2014)
6) D3 Pocket Primer (2014)
• “WebGL: Up and Running” (Tony Parisi)
Co-creator of VRML and X3D

Svcc 2013-d3

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