News from Logilab and our Free Software projects, as well as on topics dear to our hearts (Python, Debian, Linux, the semantic web, scientific computing...) |
Three of us from Logilab are going to San Francisco to listen, share and discuss at Google I/O.
It's a two day developer gathering in San Francisco, with various talks about google technologies : http://code.google.com/events/io/
We're hoping to show and talk about LAX (http://lax.logilab.org) which uses Google AppEngine
How can I test if a python float is "not a number" without depending on numpy? Simple, a nan value is different to any other value, including itself:
def isnan(x):
return isinstance(x, float) and x!=x
Here are a few pictures from the sprint we organized at Pycon-FR
We got a few people to install Google AppEngine and LAX on their machines, and explained the concepts at hand to a bunch of other people.
Update: LAX is now included in the CubicWeb semantic web framework.
This is how easy it is to get lax to run on your linux machine :
hg clone http://www.logilab.org/hg/lax/ wget http://googleappengine.googlecode.com/files/google_appengine_1.0.2.zip unzip google_appengine_1.0.2.zip ./google_appengine/dev_appserver.py lax/skel/
Point your favorite browser to http://localhost:8080/
UPDATE: LAX is now included in the CubicWeb semantic web framework.
I co-organized the Web2.0 conference track that was held at Solutions Linux 2007 in Paris last week . Researching to prepare the talk I gave, I came accross microformats and GRDDL. Both try to add semantics on top of (X)HTML.
Microformats uses the class attribute and the "invisibility" of `div` and `span` to insert semantic information, as in ::
<li class="vevent">
<a class="url" href="http://www.solutionslinux.fr/">
<span class="summary">Solutions Linux Web 2.0 Conference</span>:
<abbr class="dtstart" title="20070201T143000Z">February 1st 2:30pm</abbr>-
<abbr class="dtend" title="20070201T18000Z">6pm</abbr>, at the
<span class="location">CNIT, La Défense</span>
</a>
</li>
GRDDL information is added to the `head` of the XHTML page and points to an XSL that can extract the information from the page and output it as RDF.
Another option is to add `link` to the `head` of the page, pointing to an alternate representations like a RDF formatted one.
Firefox has add-ons that help you spot semantic enabled web pages: Tails detects microformats and the semantic radar detects RDF. Operator is an option I found too invasive.
As for my talk, it involved demonstrating CubicWeb, the engine behind logilab.org, and querying the data stored at logilab.org to reuse it with Exhibit.
This is how we setup PCL <http://trac.gispython.org/projects/PCL> under debian. Of course having a package would be better...
Install dependencies
apt-get install mapserver-bin python-mapscript mapserver-cgi gdal-bin python-gdal python-dev libgeos-dev libgdal-dev libgd2-xpm-dev python-setuptools zope-interface python-elementtree
Now link libgdal.a to libgdal1.3.2.a
Install PCL from sources
svn co http://svn.gispython.org/svn/gispy/PCL/trunk cd PCL/ cd externals/OWSLib python setup.py install --prefix=my_python_library cd externals/QuadTree python setup.py install --prefix=my_python_library cd PCL-Core python setup.py install --prefix=my_python_library cd PCL-GDAL python setup.py install --prefix=my_python_library cd PCL-MapServer
Put in a directory the source code of mapserver corresponding to the package version installed above. Get it from http://mapserver.gis.umn.edu/download or with dpkg-src.
Edit setup.py to set ms_home to the path of the above mapserver sources.
python setup.py install --prefix=my_python_library
my_python_library now contains Python eggs and directories with Python and C libraries.
CMFProjman has been asleep for quite a while, and is now being reanimated to work with Plone2. We will release it as soon as we see it's stable.