Nov 052008
Yesterday I took a look at the Google APIs for visualization; the gallery is poor for data visualization, I think. Anyway, an idea came to my mind – to make use of the MotionChart to demonstrate the Brownian Motion. Random numbers can be generated from R and read into JavaScript (the
DataTable object in Google API). Here is an example:
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("visualization", "1", {packages:["motionchart"]});
google.setOnLoadCallback(drawChart);
function drawChart() {
var data = new google.visualization.DataTable();
data.addRows(750);
data.addColumn('string', 'point');
data.addColumn('number', 'year');
data.addColumn('number', 'X');
data.addColumn('number', 'Y');
data.setValue(0, 0, "01");
data.setValue(0, 1, 1901);
data.setValue(0, 2, 1.24);
data.setValue(0, 3, -0.37);
data.setValue(1, 0, "02");
data.setValue(1, 1, 1901);
data.setValue(1, 2, 0.12);
data.setValue(1, 3, 0.48);
data.setValue(2, 0, "03");
data.setValue(2, 1, 1901);
data.setValue(2, 2, -1.5);
data.setValue(2, 3, -1.21);
....
data.setValue(748, 0, "14");
data.setValue(748, 1, 1950);
data.setValue(748, 2, 1.73);
data.setValue(748, 3, -2.24);
data.setValue(749, 0, "15");
data.setValue(749, 1, 1950);
data.setValue(749, 2, 2.38);
data.setValue(749, 3, 16.65);
var chart = new google.visualization.MotionChart(document.getElementById('chart_div'));
chart.draw(data, {width: 600, height: 500});", " }
</script>
<div id="chart_div" style="width: 600px; height: 500px;"></div>
[Preview Brownian Motion with GoogleVis API]
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5 Responses to “Brownian Motion Using Google Visualization API and R”
Comments (5)
I have included a demo function
g.brownian.motion()in the R package “animation”:if(!require("animation")) install.packages("animation") library(animation) g.brownian.motion(15, digits = 2, width = 600, height = 500)What is a good api for visualization?
What I meant by saying “poor” for GoogleVis API was: it has very limited capability of drawing genuine statistical graphics, e.g. histogram/density curve, boxplot, scatter plot with regression line or LOWESS curve, not to mention sunflower scatter plot, conditional density plot, contour plot/lines, mosaic plot, …
To the general audience, the bar/line/pie chart are much more common and easy to understand, but what they reveal is just the original data (or numbers) — little summary, no statistical inference and hence limited information.
For your question, I haven’t found a good API for (general) data visualization yet. There might be good ones for specific tasks, I think.
I know I am a bit late with the comment, but what do you think about Dojo?
Aren´t there any possibilities for data visualisation as well and beyond Google API?
I’ve never tried Dojo; thanks for pointing it out. Just now I looked at some demos and it seems to be useful. And sorry, I don’t know much about web applications for data visualization.