Regina crafted matrix of functions available in upcoming PostGIS 1.5. Currently, PostGIS 1.5 is available from trunk in the Subversion repository.
The PostGIS 1.5 documentation is available under the manual-svn node and here is the PostGIS Function Support Matrix.
Regina, great job!
By the way, there is an interesting problem with check marks. does anyone know how to define check marks based on Unicode and make them visible in IE8?
Having problems with understanding semantic of EMPTY geometry?
Paul Ramsey has started wrapping up a proper article on PostGIS Wiki explaining most of the issues related to understanding of emptiness of geometries bothering the community of PostGIS users, and OGC standards users in general.
Check it like it’s hot DevWikiEmptyGeometry. Thanks Paul!
My countryman Bartosz Milewski – the author of one of the best C++ introductory books – the C++ In Action posted video with very interesting talk about Ownership Systems against Data Races (video is here).
Interestingly, Bartosz proposes to understand the battle with data races as a discipline-driven programming that helps, mostly C+ programmers, to avoid all this horrible pitfalls. Moreover, Bartosz presents programmers with a well-designed methodology based on types system as a tool that may guard programs against injury from data races problem and with success.
Basically (and not surprisingly) Bartosz recommends think first, act later kind of approach based on detailed analysis of what might be causing data races in your program, on identification of potential sources of data race problems. This approach is a contrary to spending hours searching for data races conditions using debugger.
The data race problem is a complex subject, but – in my opinion – Bartosz explains it in a very accessible step-by-step form. Three words summary of Bartosz’ lecture and the presented methodology is: sharing + mutability + no synchronisation = data race
My friend Jo asked on GEOS mailing list for approachable explanation of spatial relations and Dale Lutz from Safe Software suggested something I’ve not came across myself before and what (in generalised form) I’d consider as a great idea for…a book really :-)
Continuing my tale about loading big raster datasets into PostGIS database with WKT Raster extension, I’d like to post an update about experience with processing overviews.
For testing purposes, I built excessive number of overviews for japan.tif dataset using gdaladdo utility:
$ gdaladdo -r average japan.tif 2 4 8 16 32 64 128
The command above produced 7 overviews with the following dimensions:
$ gdalinfo japan_2_4_8_16_32_128.tif | grep -m 1 Ov Overviews: 7000x7000, 3500x3500, 1750x1750, 875x875, 438x438, 219x219, 110x110
It really must be very hot and fresh news, so the virtual devil spirit of social networking hasn’t fished it out yet and also Google (check this if you haven’t heard yet about this local family company) lists less than 15 pages.
PostGIS provides over 300 spatial operators, spatial functions, spatial data types and spatial indexing enhancements. If you add to the mix the complimentary features that PostgreSQL and other PostgreSQL related projects provide, then you’ve got one jam-packed powerhouse at your disposal well suited for hardcore work as well as a valuable training tool for spatial concepts.
Three words: PostGIS In Action. The first book about PostGIS spatial database being written by Regina O. Obe and Leo S. Hsu with release planned for the beginning of 2010. First chapter of the book has been published and is freely available as PDF file through the Manning Early Access Program. Chapter two and three are also available for MAEP subscribers.
Next to the early access, another cool thing about the way Manning Publications release their books is possibility to comment chapters and discuss with authors directly through Manning Sandbox forums. There is no exception for the PostGIS in Action :-)
Update 2009-05-08T23:08:21+00:00: The book official announcement has been posted on postgis-devel and postgresqlonline.com.
I’m looking forward to grab the book!
Pierre, check the TOC for chapter thirteen. Cool, isn’t it?
Oracle Buys Sun. Tom asked What this will mean for MySQL?. I can make a wager this is going to happen:
Anybody is going to predict what will happen to Java?
Update 2009-04-22 09:09:07: Sun and Oracle: End of a beautiful dream – Open source goes to work by Gavin Clarke, The Register.