Wikipedia Page Analysis

Wikipedia has lots of scientific information, however, due to its nature, it is still not considered as a research resource.  This doesn’t mean it has to be ignored. I have checked some pages related with various topics in GIS field. Most of them are well-written, the information are actually quite accurate, several contributors are the professionals in the field. In this post, I like to check some metadata information of  “Mathematica” Page on Wikipedia, it may gives us some ideas about its quality.

Tools we need: Mediawiki API and Mathematica. There are plenty examples on how to use Mediawiki api. Basic procedure is to use Import[queryurl,”XML”], then parse xml to get the information we need.

Page revision history:

(* import  contributor and timestamp *)

url = "http://en.wikipedia.org/w/api.php?action=query&prop=revisions&\
titles=Mathematica&rvprop=user|timestamp&rvlimit=500&redirects$rvuser&\
format=xml";

xml = Import[url, "XML"];
rawdata= Cases[xml, XMLElement["rev", w_, _] :> w, Infinity];
data = {"user", "timestamp"} /. rawdata;

 

 

This page is constantly revised, we probably can assume the information on “Mathematica” page is up-to-date.

The information on the contributors is also interesting.

 

We can dig out more information on the contributors:

(* import paged edited by each user *)

userpages[usr_] :=
  Module[{url, uxml, udata, unicase},
   url = "http://en.wikipedia.org/w/api.php?action=query&list=\
usercontribs&uclimit=500&format=xml&ucuser=" <> usr;
   uxml = Import[url, "XML"];
   udata = Cases[uxml, XMLElement["item", w_, _] :> w, Infinity];
   unicase = DeleteCases[Union["title" /. udata ],
     x_ /; (StringMatchQ[x, "User talk:" ~~ __] || StringMatchQ[x, "Talk:" ~~ __] || StringMatchQ[x, "User:" ~~ __])]; Map[usr -> # &, unicase]];

 

The common pages edited by these top5 contributors:

  

From the pages they have edited, they have worked on several topics closely related with Mathematica. This looks good, we may say they probably know what they are doing.

Update:

Download Wikipedia Notebook for the details.

How to make a Ternary Plot

For the reader who are curious about the post on Ternary Plot


The code is very simple, here is the mathematica notebook, and the pdf version if the notebook somehow doesn't work.

Sorry for the late reply, I seldom check the comments for the older posts.

Colorful Words

Rasterize, then coloring

Google Chart API

The Google Chart API lets you dynamically generate charts.

The basic format:
http://chart.apis.google.com/chart?<parameters>

It is the most straightforward solution for web application to display dynamic graphs. I am wondering if Wolfram can come up something similar, not the webMathematica, just a simple free image generator will be great, it is definitely a good way to get more publicity.

Learning regular expression

I am learning Regular Expression right now. Here is the example to pull the information on monthly posting activities of Mathematica Discussion Group.

url = "http://groups.google.com/group/comp.soft-sys.math.mathematica/about";
reg = "(?<=month/)\\d+-\\d+\">\\d+";
data = Import[url, "Source"];
ex = StringCases[data, RegularExpression[reg]];
ds = ToExpression[StringSplit[ex, {";", "-", "\">"}]];

Then we can use DataListPlot to produce a nice graph.

Tip: Orthographic view of 3D graphics

The orthographic view of the 3D plot can be generated by using ViewPoint option. It comes very handy in some situations.

data = RandomReal[1, {20, 3}];
ListPlot3D[data, InterpolationOrder -> 0, ColorFunction -> "Rainbow", Mesh -> None, Boxed -> True, Axes -> None]
Add option ViewPoint->{0,0,Infinity} and draw it again.

Then we can put together a nice bounded Voronoi diagram. It saves the trouble to use BoundedDiagram from Computational Geometry Package.

Tip: Counting Files by Date

We like to know the number of the certain special type file processed month by month.
The following code will do the job:

(* all the files under one base direcotry *)
SetDirectory[basedirectory]
(* find all the files in all the subdirectories*)
files = FileNames["*.byt", {"*"}, Infinity];
(* return {year, month} for each file *)
data = Take[FileDate[basedirectory <> "\\" <> #], 2] & /@ files;
(* sort then count *)
cs = Tally[Sort[data]];
(* draw the graph *)
DateListPlot[cs, Filling -> Bottom, FillingStyle -> Blue, PlotStyle -> {Red, PointSize[Large]}, PlotRange -> {{{2006, 1}, {2008, 2}}, Automatic}, DateTicksFormat -> {"MonthShort", "/", "YearShort"}]

Old Time Fun: Ternary Plot

Here is the ternary plot of the 140 named colors supported by modern browsers. Actually, only 139 colors are drawn in the graph. There is no place for Black (RGBColor[0,0,0]), the center is White, however, you can't see it on the white background.

Old Time Fun: Hilbert Curve

At the time I started learning Mathematica (maybe version 3.0), it is almost impossible for any student not to plot space filling curves or other fancy fractals. Except for eye candy, it is quite useless for most of us. Today, it can't even be counted as eye candy any more.
Here is mine, Hilbert Space Filling Curve, which I found in pile of old files, the only thing that warms my heart a bit is that I come up with 4 dimensional version. You probably don't see 4D ones quite often. Of course, it has to be projected into 3D in some way for displaying.