Archive for December, 2006

libTiff to support BigTiff by July 2007 0

Posted December 25, 2006

Just heard that libTiff which is used in GDAL for GeoTiff support has found sponsors to implement BigTiff support. This will mean an end to the 4Gig limitation of GeoTiffs. These changes to libTiff will filter down to GDAL and a number of Open Source Geospatial packages like Mapserver. The detailed implementation plan can be found here.

postgis template database 1

Posted December 24, 2006

Some might find this useful for creating PostGIS databases without having to be postgresql superusers. The idea is to create a template_postgis database, install plpgsql and postgis into it, and then use this database as a template when creating new PostGIS databases.

$ psql template1
\c template1
CREATE DATABASE template_postgis WITH template = template1;
 
-- set the 'datistemplate' record in the 'pg_database' table for
-- 'template_postgis' to TRUE indicating its a template
UPDATE pg_database SET datistemplate = TRUE WHERE datname = 'template_postgis';
\c template_postgis
CREATE LANGUAGE plpgsql ;
\i /usr/share/postgresql/contrib/lwpostgis.sql;
\i /usr/share/postgresql/contrib/spatial_ref_sys.sql;
 
-- in a production environment you may want to 
-- give role based permissions, but granting all for now
GRANT ALL ON geometry_columns TO PUBLIC;
GRANT ALL ON spatial_ref_sys TO PUBLIC;
 
-- vacuum freeze: it will guarantee that all rows in the database are
-- "frozen" and will not be subject to transaction ID wraparound
-- problems.
VACUUM FREEZE;

Now non-superuser’s can create postgis db’s using template_postgis:

createdb -h host-name my_gisdb -W -T template_postgis

Trying out Geoserver + Googlemaps 3

Posted December 15, 2006
karachi_small
With a dearth of street data for Pakistan on the default mapping resource of the world (Googlemaps) I decided to try putting up some of the data I had lying around the house. Using Geoserver as a WMS layer on top of Google maps results were quite impressive. Here's Karachi and the tomb of the founder of Pakistan (M. A. Jinnah).

One can get some impressive results using the SLD support in Geoserver WMS. The site is not live yet but it will be soon. I am just trying to come up with something a bit more useful than pretty roads.

Open Source Developer’s Conference 2006, Melbourne, Australia 0

Posted December 5, 2006

OSDC 2006 OSDC 2006 starts tomorrow in Melbourne with a keynote from Randal Schwarts. Today I attended the pre-conference tutes which included a most usefull session by Jonathan Oxer. The talk titled "Large Scale Webapps: DevTeam Infrastructure" gave a run down on how software development process at his company is automated and streamlined. The automation process includes documentation, automated migration from development to testing, to packaging and releasing. You can find a more detail here. Earlier today I gave a tute on GIS Python Hacks based roughly around the workshop by the same name from Howard Butler and Shean Gillies at OSGIS'05. I'll put my slides online by tomorrow. The topics covered GDAL/OGR, GEOS and WFS with hands on snippets of code. We also did some promotion for the newly formed Open Source Geospatial Foundation.

UPDATE: Download the tutes: 
WFS_tute.zip, OGR_tute.zip, GDAL_tute.zip