Online Trick

The outcome presented above will not be very useful to most of you - still, this could be a good example for what possibly can be done via webscraping in R.

Background: TIRIS is the federal geo-statistical service of North-Tyrol, Austria. One of many great things it provides are historical and recent aerial photographs. These photographs can be addressed via URL's. This is the basis of the script: the URL's are retrieved, some parameters are adjusted, using the customized addresses images are downloaded and animated by saveHTML from the Animation-Package. The outcome (HTML-Animation) enables you to view and skip through aerial photographs of any location in North-Tyrol, from the year 1940 to 2010, and see how the landscape, buildings, etc. have changed...

View the script HERE.

NOTE: You'll find the update HERE and HERE.

NOTE: The script is currently not working because the code of the Google-Scholar site has changed...
I'll see for this as soon as I find some spare time for it!

NOTE: If you try to access GoogleScholar programatically consider this words of caution:
http://stackoverflow.com/questions/7523961/google-scholar-with-matlab/7587994#7587994
...

Based on my previous post on Web Scraping I coded and uploaded the Function "GScholarScraper" HERE for testing!
The function will pull all (!) results, processing pages in chunks of 100 results/titles, and return a file with all titles, links, etc. It will also produce a word cloud using the words in the publication titles.

Please try your own search strings and report errors, etc.!

Build and run properly under:
R version 2.13.0 (2011-04-13) and R version R-2.13.2 (2011-09-30)

Platform: i386-pc-mingw32/i386 (32-bit) locale:
[1] LC_COLLATE=English_United States.1252
[2] LC_CTYPE=English_United States.1252
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United States.1252

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] stringr_0.5 tm_0.5-6 wordcloud_1.2 Rcpp_0.9.7

loaded via a namespace (and not attached):
[1] plyr_1.5.1 slam_0.1-23

PS: Errors reported lately (see comments) were resolved, the source code was updated..

NOTE: Please see the update HERE and HERE!

...When reading Scott Chemberlain's last post about web-scraping I felt it was time to pick up and complete an idea that I was brooding over for some time now:

When a scientist aims out for a new project the first thing to do is to evaluate if other people already have come along to answer the very questions he is about to work on. I.e., I was interested if there has been done any research regarding amphibian diversity at regional/geographical scales correlated to environmental/landscape parameters. Usually I would got to Google-Scholar and search something like - intitle:amphibians AND intitle:richness OR intitle:diversity AND environment OR landscape - and then browse thru the results. But, this is often tedious and a way for a quick visual examination would be of great benefit.

The code I present will solve this task. It may be awkward in places and there might be a more effective way to yield the same result - but it may serve as a starter and I would very much appreciate people more literate than me picking up the torch...

For my example-search it is shown that there has not been very much going on regarding amphibian diversity correlated to environment and landscape...

See code HERE.

PS: I'd be happy about collaboration / tips / editing - so feel free to contact me and I will add you to the list of editors - you then could edit / comment / add to the script on Google Docs.

...some drawbacks need to be considered:

• Maximum no. of search results = 100
• Only titles are considered. Additionally considering abstracts may yield more representative results.. but abstracts are truncated in the search result and I don't know if it is possible to retrieve the full abstracts.
• Also, long titles may be truncated...
• A more illustrative result would be achieved if one could get rid of all other words than nouns, verbs and adjectives - don't know how to do this, but I am sure this is possible.
• more drawbacks? you tell..
  

In R it's quite easy to pull out anything from a webpage and I'll show a little exercise in doing so. Here I retrieve all blog addresses from R-bloggers by the function readLines() and some subsequent data processing.

# get the page's html-code
web_page <- readLines("http://www.r-bloggers.com")

# extract relevant part of web page:
# missing line added on oct. 24th:
ul_tags <- grep("ul>", web_page) 

pos_1 <- grep("Contributing Blogs", web_page) + 2
pos_2 <- ul_tags[which(ul_tags > pos_1)[1]] - 2

blog_list_1 <- web_page[pos_1:pos_2]

# extract 2nd element of sublists produced by stringsplit:
blog_list_2 <- unlist(lapply(strsplit(blog_list_1, "\""), "[[", 2))

# exclude elememts without propper address:
blog_list_3 <- blog_list_2[grep("http:", blog_list_2)]

# plot results:
len <- length(blog_list_3)
x <- rep(1:3, ceiling(len/3))[1:len]
y <- 1:len

par(mar = c(0, 5, 0, 5), xpd = T)
plot(x, y, ylab = "", xlab = "", type = "n",
     bty = "n", axes = F)
text(x, y, blog_list_3, cex = 0.5)