This is such great news, it deserves a post of its own. The Sextante Blog has released a video showing Sextante integration with ArcGIS. While I haven't seen the full list of tools, I've every reason to think it will include all the Sextante tools, which would for many people obviate the need for an ArcInfo ArcGIS for Desktop Advanced license, as well as Spatial Analyst, Geostatistical Analyst, and maybe others...

Tremendous news, indeed.

Ten years is both a long time, and a short time...

My friend Brandon, the Mercatorial Librarian[1]  has a post up reminding me that it's been ten years since we went to Nigeria to install computer labs and do training for professors in the Library Science department at Bayero University Kano in Kano, Nigeria.

It was that event which led me to Child Aid and doing similar work at Probigua in Antigua, Guatemala in 2005. All of which ultimately led to my Master's Thesis research on the political ecology of donated computers and e-waste in Accra, Ghana[2]. One of these days I'll really get that research published (I keep telling myself).

Anyway, it just reminds me that when I'm geeking out on this blog, or teaching about spatial databases (this fall at Portland State, GEOG 4/575, come on over), where my true passion lies.


[1] I assume this is a reference to Mercator, so how can I not like it?
[2] How many Geographers actually get scooped by National Geographic? Well, this one does. Turns out I was there at the same time as the NG guys, though they published first, obviously.

Geekery on display

The proposal that Sarah Beecroft and I wrote for the Open Source Bridge 2011 conference was accepted, as was our proposal for the Open Source GIS Desktop Smackdown, which we gave at GIS in Action (see previous post). I guess I have to post one of these badges now:

Recent goings on

Been a bit infrequent on updates, but I'm going to work on that.

Yesterday I presented at the "Open Source GIS Desktop Smackdown" as part of the GIS in Action regional conference. We presented gvSIG, OpenJUMP, and Quantum GIS. I presented gvSIG (using the OA edition), and  handily trounced the competition, largely, I think based on the modeler, and the fact that gvSIG has a number of advanced features, in particular more advanced topology tools than anything I've seen outside of Arc. Now if only the Mac interface worked better.

Locally, the PDX OSGeo group I'm part of has officially become an OSGeo chapter, which comes with, well, very little really, but I think it's important to recognize the good work that OSGeo is doing.

Oh, and finally, as part of the aforementioned GIS in Action conference, we're running an unconference tomorrow (March 31st) and a hackathon on the following day (April 1). It's not too late to sign up and attend - and it's free! More info and registration here: http://calagator.org/events/1250459876.

Hopefully future posts will have more technical content, but for now, that is all.

Voronoi Diagrams in PostGIS

I found myself in a situation where I needed to create a Voronoi diagram from a set of points using PostGIS. This isn't built in, but a little googling turned up a function written by Mike Leahy. I adapted it and made it a bit more generic, so it shouldn't require any editing to make it work for many (most?) cases.

Call it as: select * from voronoi(table_name text,table_primary_key text,geom_col text)  as (id id_type, the_geom geometry)


For example:



select * from voronoi('oregon_cities', 'id', 'the_geom_centroids') as (id integer, the_geom geometry);


The 'as' clause is required because we don't know and don't want to assume what type your primary key might be. But, because we're returning a record type, the query planner wants to know what type to expect. If you're always using the same type, say an integer for your primary key, then it would be easy to define a type thusly:


create type my_type as (id integer, the_geom geometry);


Then change the code at line 24 from 'rec record;' to 'rec record%my_type;' and you will no longer need the 'as' clause.


Code at this URL: http://db.tt/aInuiJ2.  Enjoy.